Savannah River Ecology Laboratory

The Savannah River Site (SRS), formerly the Savannah River Plant, is a U.S. Department of Energy (DOE) reservation in the United States, located in the state of South Carolina on land in Aiken, Allendale and Barnwell counties adjacent to the Savannah River. It lies southeast of Augusta, Georgia. The site was built during the 1950s to refine nuclear materials for deployment in nuclear weapons. It covers and employs more than 10,000 people.

It is owned by the DOE. The management and operating contract is held by Savannah River Nuclear Solutions LLC (SRNS) and the Integrated Mission Completion contract by Savannah River Mission Completion. A major focus is cleanup activities related to work done in the past for American nuclear buildup. Currently none of the reactors on-site are operating, although two of the reactor buildings are being used to consolidate and store nuclear materials.

SRS is also home to the Savannah River National Laboratory and the United States' only operating radiochemical separations facility. Its tritium facilities are the United States' sole source of tritium, an important ingredient in nuclear weapons. The United States' only mixed oxide (MOX) manufacturing plant was being constructed at SRS, but construction was terminated in February 2019. Construction was overseen by the National Nuclear Security Administration. The MOX facility was intended to convert legacy weapons-grade plutonium into fuel suitable for commercial power reactors.

Establishment and construction

Background

On 1 January 1947, the Atomic Energy Commission (AEC) assumed responsibility for the research and production facilities the Army's Manhattan Project had created during World War II to make the first atomic bombs. The AEC's gaseous diffusion plants at Oak Ridge produced enriched uranium and its production reactors at the Hanford Site irradiated uranium to breed plutonium for nuclear weapons. In response to the detonation of Soviet Union's first atomic bomb on 29 August 1949, the AEC embarked on an expansion program. On 31 January 1950, President Harry S. Truman directed the AEC to continue its work on all forms of atomic weapons, including the development of the hydrogen bomb.

An increase in plutonium production meant more reactors. There were concerns about the vulnerability of the Hanford Site to Soviet bombers, but considerations of cost led to the idea of a second plutonium production site being rejected in 1947 and 1948. Now, the AEC faced a new challenge: producing large quantities of tritium, which was believed to be required by the hydrogen bomb. Tritium was produced by the irradiation of lithium-6. It has a half-life of 12.3 years, so about 5.6 percent decays in a given year, requiring a continuous replenishment process, whereas plutonium-239 has a half-life of 25,000 years, so the stockpile is only reduced by weapons tests, accidents or use in warfare.

The Hanford reactors used nuclear graphite as a neutron moderator, but at a meeting on 30 March 1950, Walter Zinn from the Argonne National Laboratory argued that reactors moderated and cooled with heavy water would be more suitable for tritium production, although they could produce plutonium as well. By using heavy water as a moderator, they could be fueled with natural rather than enriched uranium. The AEC's director of production, Walter J. Williams, suggested that what was required was a new production site, a new site office, and a new contractor. For the new contractor, the AEC Commissioners turned to DuPont.

DuPont had expertise in nuclear engineering operations, having designed and built the plutonium production complex at the Hanford Site and the X-10 graphite reactor at Oak Ridge National Laboratory. It had left Hanford in September 1946, but had continued to provide assistance to the AEC. Since 1948, the president of the company had been Crawford Greenewalt, who had been DuPont's man at Hanford. The AEC formally requested that DuPont take the assignment on 12 June 1950. Greenewalt asked for a personal letter from Truman endorsing the urgency and importance of the project, which Truman provided on 25 July. The contract, which was signed on 30 September 1953, was a cost-plus-fixed-fee one, with the fee set at one dollar.

Site selection

Search

The contract with DuPont specified that it was in charge of all aspects of the project, including site selection. However, the AEC did have some input into the process. The AEC Military Liaison Committee obtained a map showing defense zones. The preferred defense zone was the First Defense Zone, which was beyond the range of Soviet bombers. It consisted mostly of the southeastern states, but excluded Florida and a strip along the coastline.

The other factor which weighed heavily on the AEC was that while an isolated location with a low population density was preferred for safety and security reasons, the commissioners did not want it too isolated. The wartime construction of government towns at Richland, Oak Ridge and Los Alamos had left the AEC with communities it had to administer and was now eager to divest itself of. If yet another government town was indeed required, then DuPont would have to administer it.

DuPont appointed Charles H. Topping to head its site selection effort. He employed a version of the criteria that DuPont had used for chemical plants. The United States Army Corps of Engineers was asked to identify government-owned reserves of in the First Defense Zone in areas that were isolated but with or so of a town or towns with a population of 25,000 to 50,000. This yielded 105 potential sites. A key criterion was the availability of cooling water: the two reactors would each require about . This reduced the number of potential sites to 84, and applying further criteria brought it down to 17. Secondary criteria included highway and railroad access, at least 125,000 kW of electric power, and stable geology with a low probability of earthquakes.

In September, as a result of the outbreak of the Korean War in June, the AEC increased the number of reactors to five, with the possibility of a sixth, power-generating, reactor. The AEC calculated that 1,800 MW was required to create enough tritium for the hydrogen bomb program, and since each of the Savannah River Reactors was sized at 300 MW, six would be required. This increased the cooling water requirement to , and cut the number of suitable sites to just five. Each production reactor would have a separation plant, so this meant twelve facilities, each of which would occupy about . The separation plants had to be at least apart and the reactors at least from any other plant. The whole area had to be surrounded by a exclusion zone from which any inhabitants would have to be removed. This increased the desired size of the site to about .

Decision

In October, the preferred region criterion was relaxed in the hope of saving by using colder water. The search was expanded to the Second Defense Zone, covering much of the northeastern, central, and southwestern U.S., to include areas with lower water temperatures and humidity. Site inspections reduced the final candidates down to four, two of which were in the First Defense Zone:
* Site Number 5 – on the Savannah River in Aiken and Barnwell Counties South Carolina, about southeast of Augusta, Georgia;
* Site Number 125 – on the Red River in Fannin and Lamar Counties in Texas and Bryan and Choctaw Counties in Oklahoma, about northeast of Dallas, Texas;
* Site Number 59 – on the Wabash River in Crawford and Clark Counties in Illinois and Sullivan County in Indiana, about southeast of Terre Haute, Indiana; and
* Site Number 205 – on the shores of Lake Superior in Bayfield and Douglas Counties in Wisconsin, about southeast of Duluth, Minnesota.

Site Number 5 emerged as DuPont's preferred location. The Savannah River had better water quality than the Red River, which would save on expensive water purification facilities. The Wabash had colder water, but Site Number 59 was in prime farm land, whereas Site Number 5 was in land considered marginal for agriculture. During site inspection, the survey team also visited, and were impressed by, the Clarks Hill Dam, which was then under construction. Site Number 205 had benefits, but these were not considered sufficient to select a site outside the preferred defense zone. The AEC was informed of DuPont's choice on 10 November 1950. Twenty-nine copies of the findings of the site survey were produced, and presented to the AEC Site Review Committee on 20 November. The Site Survey Committee had been established by the AEC in August to review DuPont's findings, and was headed by Leif Sverdrup, who had been a Corps of Engineers officer in the Southwest Pacific Area during World War II.

Two days later, seven members of the DuPont site survey team met with the AEC commissioners in Washington, D.C. The commissioners learned that DuPont was recommending the acquisition of instead of . The additional land provided river frontage as a natural boundary, secure access to the water supply, and provide flexibility in the location of pumping stations. The commissioners were unhappy that the proposed boundary involved the removal of the villages of Dunbarton, Ellenton, Jackson and Snelling. Commissioners Henry D. Smyth and T. Keith Glennan inspected the site by air and car on 26 November, and later that day the commissioners approved the acquisition. A announcement was issued on 28 November, in which the site was officially named the "Savannah River Plant" (SRP). Commissioner Sumner Pike was frank about the prospects of developing the hydrogen bomb, which he described as "somewhere between the possible and the probable". Doubts about the feasibility of the hydrogen bomb were not put to rest until the Operation Greenhouse nuclear tests in April and May 1951.

Land acquisition

Haggling over the SRP boundaries continued into December. By moving the manufacturing area slightly, the towns of Jackson and Snelling were saved, but Dunbarton and Ellenton remained within the boundary. The Supplemental Appropriation Act of 195 (Public Law 81-843 . R. 9526, approved on September 27, 1950, increased the AEC budget by $250,000,000 () to acquire land for a plant to manufacture radioactive products. Responsibility for land acquisition was delegated to the South Atlantic Division of the Corps of Engineers.

On 28 December, the Corps of Engineers was told to proceed with the land acquisition, although the precise boundaries of the site were not fixed until 11 January 1951. The surveyors commenced compiling an accurate map of the site and its ownership. A team of 13 appraisers was assembled, all with appraisal experience in South Carolina. The appraisers valued the property, and if the owner accepted the valuation, then a contract was signed. If not, then the property was condemned in the Federal district Court. The money was deposited with the court, and the owner could ask for up to 80 to 90 percent as credit against the final award. Property that was required immediately was obtained under a Federal declaration of taking.

A major case heard in May 1951 involved the Leigh Banana Crate Company, which valued its factory at $3 million (equivalent to $ million in ), while the Corps of Engineers thought it was worth half that. The government eventually had to pay out $1,280,965 (). Of the 1,706 tracts acquired, totaling , 73 percent were occupied by farmers, the majority of whom were African-American. Many were sharecroppers, although sharecropping was in decline in the region. Sharecroppers and tenants were paid for the value of crops that were already planted.

The towns of Ellenton (population 746 in 1950) and Dunbarton (population about 300) were acquired and the residents forced to relocate and 126 cemeteries were removed. About 120 black and 30 white families from Ellenton moved to the new development of New Ellenton. While black and white neighborhoods were intermingled in the old town, the new was built along modern lines, with strict racial segregation, black and white communities being divided by the highway.

Eventually, 46 percent of the land was acquired through condemnation. Strom Thurmond, a former governor of South Carolina who had run against Truman in 1948, was a partner in the Aiken law firm of Thurman, Lybrand and Simons. The firm represented many of the landholders in court, pocketing more than a third of the settlement in legal fees. Of the 646 condemnation lawsuits, 251 went to trial and 445 were settled out of court. The last of the land suits was settled on 1 April 1958.

The total cost of the property acquired was $15,582,026 (). In addition, the state of South Carolina was reimbursed $471,621 () for the cost of relocating highways and $270,673 () was spent relocating utilities. Also, 126 cemeteries with 5,894 graves, some dating back to the 18th century, were relocated at a cost of $168,749 () The total value of land acquisition came to about $19 million (equivalent to $ million in ). The site eventually encompassed .

Construction

Flexible design

Hanford, the Argonne National Laboratory, the Oak Ridge National Laboratory and the Knolls Atomic Power Laboratory all had significant input into the design of the Savannah River Plant and the training of its designers and operators. Physicists Eugene Wigner and John Wheeler were consulted. At Argonne, scientists researched the effects of irradiation on various alloys. The decision to clad the Savannah River Plant fuel elements in aluminium arose from these tests.

The AEC initially wanted DuPont to build two heavy water cooled and moderated nuclear reactor, using highly enriched uranium as fuel. DuPont adopted a flexible design approach, in which critical design issues were postponed as long as possible in the hope that the best possible design would be determined through research or consultation. Decision were taken where necessary, in awareness that they might narrow future choices. Partly this arose out of necessity, as the requirement for tritium, and therefore the balance between plutonium and tritium production, remained uncertain. At a conference in Princeton, New Jersey, in 1951, it was suggested that lithium could be placed in the weapon and the neutrons produced by nuclear fission used to generate tritium ''in situ''.

File:Historic P and R Reactor Photos - Savannah River Site (7515731418).jpg, Reactor vessel
File:Historic P and R Reactor Photos - Savannah River Site (7515731116).jpg, On 25 April 1952
File:Historic P and R Reactor Photos - Savannah River Site (7515730976).jpg, On 1 July 1952

An early design decision was to use cylindrical canned slugs for fuel. Although plates might have been easier to cool due to their larger surface area, and therefore allow the reactors to operate at greater power levels, all the experience at Hanford was with slugs. Once slugs were chosen, future choices became restricted by the tubes in the original design, and more complex shapes could not be explored. This did not prove to be a problem, as even before startup R Reactor was found to be capable of 700 MW, and in upgrades later years would permit the reactors to be run at up to 2,000 MW. On the other hand, it was found that raw river water was more effective as a coolant in the heat exchangers than treated river water, so four expensive water treatment plants were omitted. Tests also revealed that heavy water was less corrosive than the Columbia River water used as a coolant at Hanford.

Workforce

Construction required large numbers of skilled workers such as carpenters, painters, electricians, plumbers, concreters, pipe fitters and truck drivers. Within six months of the project's commencement, DuPont was hiring more than one hundred workers per day. There were national labor shortages due to the call up of draftees and reservists for the Korean War. The Davis–Bacon Act of 1931 mandated that workers on federal construction projects be paid the local prevailing wage at a minimum, but DuPont consistently paid over and above that. It could not satisfy its requirements locally, and therefore had to offer higher wages to lure workers from other parts of the country, although most came from the southeastern states.

DuPont recruited most of its workers through building trade unions associated with the American Federation of Labor. Congressman Don Wheeler alleged that DuPont was operating a closed shop in violation of the Taft–Hartley Act. There were exceptions, such as the twenty to thirty displaced residents of Ellenton that were hired, and Granville M. Read, DuPont's chief engineer denied that there was an agreement with the unions to keep non-union workers down to the minimum needed to meet the requirements of the act. Truman's 1948 Executive Order 9980 abolished segregation in the federal establishment, of which AEC was a part, but DuPont had only one black white-collar employee, and the AEC had no black employees at any level at all. Most AFL unions excluded black members, and many of those that did not kept them in segregated local branches. About 90 percent of the black people employed at the construction site were common laborers.

Construction costs

By 1 January 1956, the construction of the basic plant was complete, at a cost of $1,065,500,500 (). Works had involved of lumber, 126,000 carloads of materials, of reinforcing steel, of concrete, of structural steel, of underground water pipes, and of railroad tracks.

Defenses

Two rings of anti-aircraft gun sites were built surrounding the Savannah Plant. Four 90-mm gun sites were completed by April 1956 and a further thirteen 75-mm Skysweeper sites were under construction by September. The 30th Anti-Aircraft Artillery (AAA) Battalion arrived in 1955. It had four batteries, each equipped with four 90-mm guns. Each 90-mm gun site had a concrete barracks built to house 120 men, a mess hall, gun emplacements, a motor pool area, an administration building, and a command post. The battalion had a computerised radar fire-control system that identified and tracked targets. The 33rd AAA Battalion was soon joined by the 425th and 478th AAA Battalions, which were equipped with 75-mm Skysweeper guns. Together, the three battalions formed the 11th AAA Group, which in turn was part of the Army Air Defense Command. One of the star-shaped temporary buildings used during construction was refurbished for military use. The anti-aircraft guns were supposed to an interim measure, to be replaced by Nike Hercules missiles, but this never occurred. In 1957, the 33rd AAA Battalion departed, the 425th and 478 were disbanded, and further military construction was cancelled. The Army presence at the Savannah River Plant ended in 1960, leaving the protection of the site to the US Air force and its jets from surrounding airbases throughout South Carolina and Georgia.

Cold War era operations (1950s–1980s)

Nuclear weapon program

The Savannah River Plant, as SRS was known until 1 April 1989, was constructed in the 1950s to produce basic materials for nuclear weapons, primary tritium and plutonium-239, in five nuclear reactors by irradiating target materials. It featured two chemical separation plants, known as "canyons", a heavy water extraction plant, a nuclear fuel and target fabrication facility, and the corresponding nuclear waste management infrastructure (landfills, waste seepage basins, waste tanks, and waste conditioning facilities). Nuclear material production for defense purposes ceased mid-1988. Over the thirty years of operation, the Savannah River Plant produced about 36.1 metric tons of weapons-grade plutonium.

Nuclear arms race

The Manhattan Project relied on graphite-moderated air-cooled nuclear reactors to produce fissionable materials, even though heavy water offered superior neutron moderation properties to graphite. Heavy water had the added advantage of being both a moderator and a coolant. These properties made it a theoretically ideal choice for production reactors, but the scarcity of heavy water during World War II made its large-scale use impractical, leaving graphite as the only viable option, despite its limitations.

The very first nuclear reactor to operate at Savannah River Plant was the 305-M graphite test pile. The low power (30 watt) test reactor went critical in September 1952 and operated until 1981. It was primarily used to measure the reactivity of fuel metals and other reactor component materials. Several other test reactors were later built in the Physics Assembly Laboratory, like the Process Development Pile that was instrumental in optimizing the chemical and physical parameters for plutonium and tritium production.

The design of the Savannah River Plant production reactors was based primarily on the Zero Power Reactor II, a small heavy water reactor commonly referred to as "ZPR-II", at Argonne National Laboratory. The AEC and DuPont finally accepted Argonne's conceptual production reactor design "CP-6" at the end of 1950.

The first reactor built at Hanford during the war, B Reactor, was operational within 21 months of the start of construction, and D and F Reactors took twenty-seven months. Construction of the first reactor at the Savannah River Plant, R Reactor, was begun in June 1951, and was completed in July 1953, twenty-five months later. R Reactor became operational in December 1953; the Savannah River Plant reactors required a longer period of testing and tweaking before becoming fully operational. If slow by Hanford standards, this was much faster than later generations of nuclear engineers would be able to achieve.

P, L, and K Reactors followed in February, July and October 1954, respectively, and the first irradiated fuel was discharged, from R Reactor, in March 1955. C Reactor went critical in February 1955.

As the operators became more familiar with the reactors, they found that the power levels could be increased. C Reactor was built with twelve heat exchangers, but the others had only six due to limited supplies of heavy water and a shortage of heat exchangers. In 1956, the number of heat exchangers was increased to twelve on all five reactors, and the power output was increased from 378 MW to 2250 MW. This in turn meant that the cooling water, which was discharged back into the river, was hotter. A cooling pond, known as the P and R (or Par) Pond, was constructed in 1958 to allow water to cool before being discharged. P and R Reactors could also draw on Par Pond for cooling water, thereby saving pumping costs, and it made more river water available to the other reactors. The allowed C Reactor's power level to be raised to 2575 MW in 1960, and then to 2915 MW in 1967.

In the late 1950s, SRP pioneered the use of computers to enhance the productivity and safety of the production reactors. The operation of these reactors had become increasingly complex owing to the extensive manual oversight required to control various nuclear fuel types and to monitor targets irradiated at increasing high specific powers in 600 fuel positions. The first mainframe computers installed in any of the productions reactors were the General Electric GE-412. The utility of on-line computers for process control was first demonstrated in 1964, when they were used to process data from about 3,500 reactor process sensors and to alert operators to faulty instrument signals in the K reactor. By the end of 1964, this system was scanning more signals than any computer in the United States. As a result, on-line computers were installed in the three other then-operating reactors by the end of 1966. In 1970, a closed loop control system of the K reactor power began trial operation. Computers were used to control reactor power by moving its control rods in a stepwise manner, optimizing reactor performance. Closed-loop computer control was used for about 90% of a reactor production cycle. In 1971, K Reactor had become the first nuclear reactor to be controlled by computer. In the late 1970s, new computer systems were installed to provide dual safety functions and automatic safety backup functions. Following the lessons learned from the 1979 Three Mile Island accident, SRP computerized the automatic diagnosis alarms in 1982, using fault tree analysis to support plant operators in accidental situations.

By 1964, the United States had nine graphite-moderated production reactors at Hanford and five heavy-water production reactors at the Savannah River Site operating and upgraded with over 36,000 MW of production capacity in service. In comparison, fewer than 750 MW were needed to produce the strategic material for the Trinity test and Fat Man.

Détente

In his 8 January 1964 State of the Union Address, President Lyndon B. Johnson announced a reduction in nuclear materials production, ostensibly as part of an initiative to slow the nuclear arms race, but in fact because production had outstripped demand. In 1964, there were nine production reactors at Hanford and five at the Savannah River Plant. The announcement was followed on 22 January by the AEC ordering the shutdown of F, DR and H Reactors at Hanford, and R Reactor at the Savannah River Plant. These were chosen for being the reactors in the worst condition; R Reactor had already sprung some leaks. It was shut down on 22 April 1964, but did not go quietly; during initial preparations, there was an unexpected power surge from 500 MW to 925 MW within 2.5 minutes. This was one of the three worst reactor incidents at the SRP.

File:PARadise (51507029331).jpg, Par Pond
File:H Canyon Crane Control Room (4731038948).jpg, H Canyon crane control room

D Reactor was shut down at Hanford in 1967, and in January 1968, AEC chairman Glenn Seaborg announced that another reactor would be shut down at Hanford (B Reactor was selected) and one more at the Savannah River Plant. Although C Reactor had a history of leaks, L Reactor was chosen for shutdown, because C Reactor was used for tritium production and reconfiguring L Reactor would have cost more money.

By 1972, all the Hanford production reactors and reprocessing activities had been shut down and N Reactor converted to maximize electricity production. The nuclear weapons production complex was reduced to just 4 production reactors: P, K, and C reactors at Savannah River Plant, able to keep pace with demand by operating at high power levels, and N reactor at Hanford. The F and H canyon reprocessing facilities continued to operate. The last of the heavy water production units at the Savannah River Plant was closed in 1982.

Restart of plutonium production and reactor closures

By 1980, détente between the United States and the Soviet Union was starting to fray. The Soviet Union deployed SS-20 intermediate-range ballistic missiles in Eastern Europe, each carrying three nuclear warheads and capable of striking NATO bases and cities in Western Europe with little warning. As a reaction, NATO decided to deploy US Pershing II missiles and BGM-109G Ground Launched Cruise Missiles in Western Europe in an attempt to counter the SS-20 deployment, known as the NATO Double-Track Decision. The United States decided to increase fissile materials production to support a nuclear weapons modernization program.

On 11 April 1980, Secretary of Defense Harold Brown expressed doubts about the ability of the new United States Department of Energy (DOE) to meet the needs of the military-industrial complex. The need for a new production reactor (NPR) was debated in Congress, but the advocates of certain sites and technologies tended to cancel each other out, and years went by without action.

File:D Area Powerhouse Control Room (7977438905).jpg, D Area Powerhouse Control Room
File:D Area Powerhouse at SRS (7977695819).jpg, D Area Powerhouse

N Reactor at Hanford started producing plutonium again in 1982 and reprocessing in 1983. To meet the immediate need, the DOE decided to restart L Reactor. The effort had a budget of $214 million (equivalent to $ million in ) and a workforce of 800 for the renovation effort. It was the first time that a reactor on standby had been restarted after a hiatus of more than a decade. Asbestos insulation was removed and cooling pipes were replaced. The heat exchangers (and those of the R Reactor) were found to be in very poor condition, and repair was uneconomical. No bids were received from US firms, so the contracts for new heat exchangers were awarded to two Japanese firms, Hitachi and Mitsui. Various safety upgrades that had already been installed on the other reactors were added. These included a new console, computer systems for control rod operations, and an improved emergency cooling system. Twelve years' worth of pigeon fecal waste had to be removed from the stack area.

By June 1983, the project was ahead of schedule and $10 million under budget, but then it hit a snag in the form of a series of lawsuits from individuals and organizations concerning the discharge of hot water into Steel Creek and of caesium-137 from Steel Creek into the Savannah River. An environmental impact assessment was prepared, which found that the Savannah River water temperature would remain well under the mandated by South Carolina law, and that the level of caesium-137 in river water immediately downstream would be 1/20,000^th of the United States Environmental Protection Agency (EPA) standard for drinking water.

Nonetheless, using Steel Creek as a sacrifice zone was no longer considered environmental best practice, and the discharge of of water at would have been a violation of the standards for a commercial reactor. To meet the objections, construction of a large cooling pond known as L Lake commenced in 1984. It was completed in 1985, allowing L Reactor to go critical again on 31 October 1985. The temperature of L Lake was kept to , which sometimes required restricting reactor operations in the summer months.

The DOE decided to produce weapon-grade plutonium by recovering the fuel-grade material produced in the N reactor since 1966 and by blending it with supergrade plutonium to produce weapon-grade plutonium. In 1985, the DOE configured the Savannah P, K, and C reactors to produce 2.8 tons of plutonium with 3% content ²⁴⁰Pu for that purpose.

File:211486 K Area Aerials 11-11-21 002 (54439533593).jpg, K Reactor
File:211485 L Area Aerials 11-02-21 010 (54438425802).jpg, L Reactor
File:Aerial of P Reactor at SRS (5108119000).jpg, P Reactor
File:C Area 105-C Aerial 1-25-18 002 (54439472104).jpg, C reactor

Meanwhile, C Reactor was shut down in June 1985 following another leak, and was not restarted after unsuccessful attempts to repair it. In March 1987, power level limits were instituted on K, L and P Reactors due to problems with the emergency core cooling system and the increased risk of loss-of-coolant accident. Congress asked for sprinkler systems to be installed in the reactor buildings, but DuPont resisted this on the grounds that concrete structures did not easily burn.

K reactor were put in an outage status in April 1988, L Reactor in June, as part of their normal operations but their restart never happened. The August 1988 incident during the P reactor's startup attracted a lot of media attention, triggered congressional hearings, and spurred the decision to implement much-needed nuclear safety improvements, enhance operator qualifications, and bolster management oversight before restarting any of the production reactors. A Congressional committee hearing in September 1988 revealed a long list of nuclear incidents at SRP and received copy of an internal report listing over thirty significant incidents at the facility. These included: the near loss of control of L Reactor in 1960 when technicians tried to restart it; the "very significant leak" of water from the C Reactor in May 1965 when of heavy water was spilt on the floor; a large radiation release in November 1970; and a melting of fuel rods in the C Reactor in December 1970. What began as a temporary halt soon became permanent. By April 1989, when Westinghouse took over from DuPont, the United States had completely ceased the production of weapons-grade plutonium. Between 1988 and 1993, the DOE invested over $2 billion in refurbishing the K, L, and P reactors, but this refurbishment program was terminated, and the reactors remained shutdown.

In 1997, the United States and Russia entered into an agreement aimed at halting the production of weapon-grade plutonium. Under the terms of the agreement, Russia's three active plutonium-producing reactors were to be converted by 2000 to eliminate their capacity to produce weapons-grade plutonium, while prohibiting the United States and Russia from restarting any plutonium producing reactors that had already been shut down.

Chemical separation plants

F Canyon, the world's first operational full-scale PUREX separation plant, began radioactive operations in April 1954. PUREX (plutonium and uranium extraction) extracted plutonium and uranium from materials irradiated in the reactors. Plutonium was then stored as metal and uranium as an oxide.
This processing resulted in the production of large amounts of highly radioactive liquid waste that were transferred for storage in two underground H- and F-tank farms at the site. The first plutonium shipment left the site on 28 December 1954. H Canyon, the second chemical separation facility, began operations in March 1955.

File:SRS at 60 -- H Canyon (5228276930).jpg
File:SRS H Canyon (7604694068).jpg

Tritium production

Permanent tritium facilities became operational and the first shipment of tritium to the Atomic Energy Commission (AEC) was made in 1955. The tritium plant originally planned for the H area was dropped during the initial construction project due to the drop in demand for tritium by the weapons program. As its requirements evolved, an improved plant was built and all tritium production shifted to the H area in 1958. Tritium produced in the K reactor was finally transported to Mound Plant, a nuclear weapons research laboratory in Ohio, for purification by removing impurities and helium-3, considered a waste product and vented to the atmosphere.

Heavy water production

Heavy water is a form of water that contains two atoms of the hydrogen isotope deuterium, rather than the common protium isotope that makes up most of the hydrogen in ordinary water. Zinn's heavy-water-moderated reactors would each require up to of heavy water, but the global inventory of heavy water in 1950 was less than 50 tons. During the war, the Manhattan Project's P-9 Project had produced heavy water at three DuPont munitions plants: the Morgantown Ordnance Works, near Morgantown, West Virginia; at the Wabash River Ordnance Works, near Dana, Indiana, and the Alabama Ordnance Works, near Sylacauga, Alabama. They used a distillation process to extract heavy water from ordinary water, based on the slightly higher boiling point of heavy water. Final concentration was done by an electrolysis process at Morgantown, which used the property that heavy water did not dissociate under electrolysis as readily as light water. The production process was not very efficient, but the P-9 Project supplied 6.5 tons of heavy water that was used in CP-3, the world's first heavy water reactor, which was designed by Zinn.

The P-9 heavy water plants had been shut down in 1945 but research continued into heavy water production, with Harold Urey and Jerome S. Spevack investigating a new process called the Girdler sulfide (GS) process. This involved mixing hydrogen sulfide () gas with water at different temperatures, under conditions where deuterium atoms prefer being bound to oxygen rather than sulfur. The AEC commissioners were initially skeptical of the new process, due its high costs, but approved the construction of a pilot plant at the Wabash River Ordnance Works. Girdler and, as a DuPont subcontractor, worked through the problems associated with the new process. The Dana pilot plant completed its first test run on 26 October 1950.

The increase in the number of reactors from two to five meant that the Wabash River Ordnance Works plant did not have enough capacity. A second GS facility was therefore authorized in January 1951, to be built at the Savannah River site in the 400-D area. This construction had top priority, as the reactors could not operate without their heavy water. Despite concerns, about of heavy water was produced by the time the first reactor, R Reactor, was ready. In addition to the GS units, the plant had twelve distillation towers for the second step, and electrolysis building for the final step. The facility had its own pumphouse to bring river water and a powerhouse to supply electricity and steam that could burn up to of coal per hour.

AEC chairman Lewis Strauss visited the SRP in March 1955, and announced that the United States was going to sell Italy of heavy water for its first research reactor. In 1956, the market price of heavy water was $28 per pound () of $14,000 per drum (). Subsequently, Australia, Canada, France, Norway, Sweden, Switzerland and the United Kingdom received heavy water under the AEC's Atoms for Peace program. Production of heavy water peaked in 1969 when was produced. In 1970, $27 million worth (equivalent to $ million in ) was sold to Canada for use in the Pickering Nuclear Generating Station. That year, of heavy water was sold for $50,656,000 (). It was the only product of the production facility that made money.

Neutrino discovery

The neutrino was a hypothetical particle whose existence was first suggested by Wolfgang Pauli in 1930 as a means of reconciling the apparent loss of energy that occurred during beta decay. There was still doubt about whether they really existed or not in 1952, when Frederick Reines and Clyde Cowan at the Los Alamos Scientific Laboratory set out to find them using a nuclear reactor, a good source of neutrinos. Their first attempts at Hanford in 1953 were unsuccessful. In 1954, their team transferred their research to the Savannah River Plant, where they set up several truckloads of equipment at the P Reactor. The neutrino detector, weighing approximately 10 tons excluding its shielding, was composed of two large, flat plastic tanks, each containing 200 liters of water with trace amounts of cadmium chloride, positioned between three scintillation detectors, which incorporated a total of 1,400 liters of liquid scintillator and 110 photomultiplier tubes in total. This time, neutrinos were detected, and they announced their discovery in the 20 July 1956 issue of ''Science''. Reines was awarded the 1995 Physics Nobel Prize for the discovery; Cowan had already died. Neutrino research continued at P Reactor, sponsored by the University of California, Irvine, until the reactor was shut down in 1988.

Heavy Water Components Test Reactor

The use of heavy water put the Savannah River Plant on a different path to the commercial nuclear power plant industry, as pressurized water reactors using enriched fuel and light water as a moderator and coolant became the technology of choice in the United States. The AEC did not give up on the idea of heavy water reactors though, and in 1956 initiated a project to demonstrate the feasibility of electric power production using heavy water and evaluate various components for their suitability in heavy water reactors. At first, it was to be a small reactor with an electric power output of 100 MW, but this was raised to 400 MW after studies indicated that 100 MW would be uneconomical. The use of heavy water would add to the capital cost, but this could be offset by the use of cheaper natural uranium as fuel instead of enriched uranium. DuPont doubted that it would be competitive with conventional fossil fuel power plants.

File:SRS at 60 -- HWCTR (5228358290).jpg, In 1964 and 2010
File:HWCTR - after decommisioning - concrete cap.png, Concrete cap after decommissioning in 2011

It was a natural choice to have DuPont build the reactor at the Savannah River Plant, as this was where all the expertise in heavy water reactors resided. It was originally planned to build it in the K Area, but AEC feared that this might compromise the security of the production reactors, so a site was chosen in the old temporary construction area adjacent to the TC-1 administrative building. Construction commenced in 1959, and after a series of delays, the Heavy Water Components Test Reactor (HWCTR, known as "Hector") was completed in October 1961, and started up in 1962. Although the suitability of heavy water reactors for power generation was demonstrated, the savings on fuel were insufficient to offset the cost of the heavy water, and the AEC decided to curtail their development. Operations at the HWCTR were terminated in December 1964 and the reactor placed in standby status. The heavy water and fuel assemblies were removed in 1965. In 2009 the American Recovery and Reinvestment Act (ARRA) provided a $1.6 billion (equivalent to $ billion in ) to seal and decommission the reactor. This work was completed in June 2011.

Despite AEC efforts to promote heavy-water power reactors, U.S. utility companies had already shown by 1962 a clear preference for pressurized light-water reactor technology that originated in the U.S. Navy's propulsion reactors program and had been demonstrated at the Shippingport Atomic Power Station. The AEC 1954 Atoms for Peace program, by providing electric utilities with enriched uranium, also played a crucial role in this choice. Consequently, the heavy-water reactor key advantage of using natural uranium became less significant, as enriched uranium grew more readily available in the United States. As a result, the Carolinas–Virginia Tube Reactor remained United States' only commercial heavy water reactor. Canada developed its own heavy water power reactor design, later known as CANDU, based on natural uranium fuel, a strategic choice given that uranium enrichment facilities at the time were predominantly operated for military purposes, despite the fact that heavy water represented up to 20% of the total capital cost of each CANDU power plant in the 1970s.

Radioisotope production

Space exploration

During the 1950s, there was also research conducted at the SRP into heat and power sources that could be used in the Arctic and in space. Early research concerned cobalt-60, which was not only a heat source, but could also be used food irradiation. Cobalt-60 was produced at the SRP between 1955 and 1967, and was used as a heat source by Distant Early Warning Line stations in Alaska, Canada and Greenland. Plutonium-238 proved to be an ideal source of heat and electricity for space exploration: it was easily shielded and with a half-life of about 88 years, it could power a spacecraft for a long mission. The AEC gave the SRS the mission of producing plutonium-238 in the late 1950s.

Plutonium-238 was produced by the irradiation on neptunium-237, a byproduct of the irradiation of uranium in the reactors. This occurred when uranium-235 captured two neutrons. This creates uranium-237, which has a half-life of 6.7 days, decaying into neptunium-237 through beta decay. The neptunium-237 was recovered and purified, and then irradiated to produce plutonium-238. When work began in the late 1950s, there was already a large body of literature on the chemistry of neptunium and plutonium. An anion exchange process was used to separate neptunium(IV) nitrate () and plutonium(IV) nitrate () from uranium. The plutonium (IV) nitrate was then reduced to plutonium (III) nitrate () and a second anion exchange process separated neptunium(IV) nitrate from plutonium (III) nitrate. The neptunium nitrate was then precipitated as neptunium(IV) oxalate (), which was heated in air to to produce neptunium dioxide () and clad with aluminium to create targets suitable for irradiation in the reactors. The processing of neptunium-237 to create targets began at SRS in 1961. Throughout the 1960s and well into the 1970s, plutonium-238 was then shipped to the Mound Laboratories as an oxalate or a nitrate and subsequently as an oxide to enter into any one of the following processes for the production of heat source materials: pressed plutonium oxide, plutonium-molybdenum cermet, or plutonium metal.

Plutonium-238 from the SRP was first used in the early 1960s by the US Navy's Transit navigation and NASA's Nimbus 3 meteorological satellites. It was taken to the Moon by the Project Apollo missions, to Mars by the Viking program, solar orbit by the '' Ulysses'' spacecraft, Jupiter by the ''Galileo'' spacecraft, Saturn by the ''Cassini–Huygens'' project, and the outer reaches of the Solar System by the Voyager program spacecraft.

In September 1971, the AEC decided to transfer from Mound Laboratories to SRS the production of plutonium-molybdenum cermet, a nuclear fuel form consisting of sintered ~80% plutonium-238 in oxide form embedded in metallic molybdenum. In 1972–1973, the original scope of the Plutonium Fuel Form (PUFF) Facility was expanded to include the fabrication of pressed plutonium-238 oxide (PPO) spheres or pellets and the iridium encapsulation of the PPO spheres to eliminate the need for transporting plutonium-238 powder in the public domain. The construction began in 1973 and became operational in 1977. Although cermet discs were never fabricated at PUFF, the production of iridium-encapsulated 100-watt PPO spheres for Multi-Hundred Watt RTGs started in 1978 and was completed in April 1980.

File:Radioisotope thermoelectric generator plutonium pellet.jpg, A pellet of Plutonium-238
File:Apollo 12 Second Look- Midday on the Ocean of Storms (LROC70 - AS12-46-6943 pluto).png, Apollo 12 astronaut Alan Bean unloads the plutonium core that powered the ALSEP on the Ocean of Storms
File:STS-34 Galileo processing at KSC's SAEF-2 planetary spacecraft facility (S89-42091).jpg, ''Galileo'' spacecraft

The general-purpose heat sources used by ''Galileo'', ''Ulysses'' and ''Cassini'' each contained seventy-two cylindrical plutonium dioxide () pellets that were fabricated at the SRP from June 1980 until December 1983. The fabrication process involved hot pressing to induce the sintering of the plutonium-238 oxide. Each pellet was approximately 2.7 cm by 2.7 cm, weighed about 150 g, and radiated 62.5 W of heat. Seventy-two of them in a radioisotope thermoelectric generator (RTG) generated about 285 W of electrical power. ''Galileo'' had two RTGs (totaling 22 kg of plutonium-238); ''Ulysses'' had one; ''Cassini'' had three.

Production of Plutonium-238 at PUFF, at a rate of about 20 kg per year, was put on hold in December 1983 and ceased definitely in 1988 when the production reactors were shutdown. Between 1978 and 1984, the PUFF facility produced approximately 165 kilograms of iridium-encapsulated PPO spheres and pellets for use as radioisotope thermal generators, primarily for the space program. This stockpile was projected to be depleted in 2018. In 2015, the U.S. Department of Energy decided to address the impending shortage of Pu-238 fuel for future NASA missions and restarted its production at Oak Ridge National Laboratory leveraging both the High Flux Isotope Reactor at Oak Ridge and the Advanced Test Reactor at Idaho National Laboratory.

Synthesis of transplutonium isotopes

The U.S. Transplutonium Production Program began in 1959 with irradiations in SRP's reactors and in the High Flux Isotope Reactor at Oak Ridge National Laboratory. The SRP also produced heavier transplutonium elements, including plutonium-242, curium-244 and californium-252. Curium-244 production began in C Reactor in May 1964. The work was done in two stages. In the first, plutonium-239 was irradiated to produce plutonium-242. In the second stage, between February 1965 and February 1966, plutonium-242 was irradiated to produce curium-244 in C and K Reactors. In the process, a small amount of californium was also created. For high neutron flux operations, cobalt-59 is preferred over lithium for the control rods, as the latter tended to melt at high temperatures. As a result, some cobalt-60 with was produced. Another curium-244 production run was carried out in K Reactor between December 1965 and May 1967. The result of all this work was 5.9 kilograms of curium-244 and about three milligrams of californium-252.

Between August 1969 and November 1970, an effort was made gram-scale amounts of californium-252 in K Reactor to develop a market development for Cf-252 neutron source applications. Eighty-six targets containing more than 8 kilograms of plutonium-242 were irradiated for ten years. Twenty-one targets were processed in 1972–1973 at ORNL to recover about 4 grams of plutonium-244, "heavy curium" (i.e., curium rich in curium-246 and curium-248) and about 2.1 grams, but an incident occurred in November 1970 when an antimony-beryllium control rod melted. The cleanup took three months, and effectively ended the Transplutonium Production Program at SRP. Production of californium-252 and other transuranium isotopes for research, industrial, and medical applications continued at the High Flux Isotope Reactor at ORNL. The DOE distribution center for californium-252 for transitioned from SRS to ORNL in the late 1980s.

Whistleblower

The case of Roger D. Wensil, a pipe-fitter, worked for the B.F. Shaw Co., a subcontractor at Savannah River Plant, stands as a significant milestone in the evolution of whistleblower protection in the U.S. nuclear sector. Dismissed in 1985 after raising concerns about safety violations and illegal drug traficking among construction personnel at a nuclear waste-handling facility at SRS, he filed a claim under the nuclear safety whistleblower law but was dismissed as it was found not apply to nuclear weapons facilities. After involving the press, DOE ordered Wensil to be rehired despite lacking any legal rights.

Wensil's case evidenced a significant deficiency in legal protections for employees working under DOE contractors. In 1992, the section 2902 "Employee protection for nuclear whistleblowers" of the 1992 Energy Policy Act, amending 1974 Energy Reorganization Act, extended the whistleblower protection to DOE contractor employees, establishing the legal framework for nuclear weapons whistleblower protection.

Environmental monitoring

DuPont started its environmental stewardship program for SRP when the Site's acquisition process was still on-going. In accordance with its company policy, DuPont decided to establish the pre-operational environmental baseline to be able to monitor the future impact of the Savannah River Plant on its environment. This stewardship later evolved into full-fledged research programs that monitored and continue to explore the impact of the site on the environmental health of the surrounding ecosystems, turning SRP into an early center of ecological activity in the United States, with research projects on old-field succession, thermal ecology, radioecology, environmental chemistry, and toxicology.

In 1950, once the contract formally awarded, DuPont integrated Ruth Patrick and her team from the Academy of Natural Sciences of Philadelphia (ANSP) into the Savannah River Projec to study the river's biological diversity prior to the operation of the planned SRP reactors, which were anticipated to elevate the river's water temperature. The land surrounding the production facilities became a protected buffer zone that would become part of the Savannah River Ecology Laboratory led by Eugene P. Odum. Their reports studied the biological conditions on the river and surrounding wetlands. Earlier studies had tended to use certain species as indicators of the health of the environment; Patrick's team examined all the major plant and animal species and noted the interaction between them, something that had not been done before on an area of this size. The methods they developed were later employed on studies of the Amazon River. After the initial survey, ANSP scientists carried out studies at three to five year intervals. Between 1954 and 1968, water as hot as was discharged into Steel Creak, resulting in the gradual destruction of the vegetation over a thirty-year period.

Biologists from the University of Georgia and the University of South Carolina began ecological studies of local plants and animals in 1951. Eugene Odum from the University of Georgia put forward an ambitious $150,000 () proposal that was rejected by the AEC on the grounds of cost and because it wanted to involve both universities. Instead, $10,000 () was given to each university. While the ANSP team focused exclusively on the aquatic ecosystems, the universities carried out terrestrial studies concomitantly. Odum began working on the site in 1951, with three graduate students, each from a different university. The University of South Carolina left after the initial survey work was completed, but the University of Georgia remained, and established the Laboratory of Radiation Ecology at the Savannah River Plant under Robert Allen Norris. In 1961, the AEC established a permanent ecology laboratory on the site, the Savannah River Ecology Laboratory (SREL), under Frank Golley. Two Army barracks were converted into laboratory space for the scientists. The site was designated as a National Environmental Research Park in 1972. A large laboratory building was completed in 1979, and in 1997 the Ecology Laboratory Conference Center was opened on the extreme northern edge of the site, near the town of New Ellenton.
The United States Forest Service was brought in August 1951 manage and protect the forests that occupied 67 percent of the Savannah River Plant reservation at that time. A large tree planting project was initiated to provide screening, prevent erosion, and control dust and the spread of noxious weeds. Seeds were collected locally, and then sent to the Forest Service's Stuart Forest Nursery in Pollock, Louisiana, established in 1933 in response to the important need for reforestation in West Virginia and eastern Texas. After nine months, they were brought to the Savannah River Plant for planting. Some 75 million seedlings had been planted by June 1960. The timber was later harvested and sold, returning $300,000 () in the 1960s and 1970s. By 1999, 72 percent of the site was forest, and the value of the timber was nearly $500 million (equivalent to $ million in ), with harvested annually for sawlogs, pulpwood and pinestraw.

The Forest Service also maintained a wildlife and botany conservation programs. The red-cockaded woodpecker was listed as an endangered species in 1970, but through the efforts of the Forest Service their numbers on site grew from four in 1970 to 120 in 2002. Other species being monitored and protected included the bald eagle, wood stork, American alligator, shortnose sturgeon and the smooth purple coneflower. In 1996, the Forest Service established the Savannah River Environmental Sciences Field Station to provide instruction in environmental sciences to university undergraduates.

File:Collecting Plant Samples (9314421995).jpg, SRNL Senior Scientist Wendy Kuhne collects plant samples along SRS Tinker Creek.
File:Characterization Lab (9496952664).jpg, SRNL postdoc Maria Kriz works on structural characterization of materials using X-Rays.

In 2007, scientists examining the high-level waste storage tanks were surprised to find a new species of radiation-resistant extremophiles inside one of the tanks. The greenish-orange slime was named Kineococcus radiotolerans. While the high level of radiation inside the tanks would have been lethal to almost any other species, this one had the ability to rebuild its DNA in four to six hours.

Archaeological investigations were initiated on the site in 1973 at the request of the DOE to comply with Executive Order 11593. The South Carolina Institute of Archaeology and Anthropology of the University of South Carolina began conducting archaeology at the Savannah River Plant in 1973 and established a permanent presence on site in 1978 as the Savannah River Archaeological Program (SRARP), which performed data analysis of prehistoric and historic sites on the land. This resulted in a greater understanding of the site's past in a series of books, journal articles and monographs.

Post-Cold war transition and cleanup operations (1990s–present)

Decommissiong and environmental remediation

Decades of nuclear material production for defense purposes, along with the site's historical waste disposal practices, have led to significant environmental contamination, the accumulation of large quantities of nuclear waste and surplus nuclear materials requiring disposal, and the need to safely decommission numerous disused facilities. Disposal techniques, such as the use of seepage basins for liquid waste and underground tanks for high-level radioactive materials, directly contaminated soil, groundwater, and surface water. This contamination posed substantial risks to the health and safety of surrounding communities and local ecosystems. Soil contamination was particularly widespread, exemplified by over 90 acres in D Area affected by coal ash disposal, the burial of soil contaminated following the 1966 Palomares incident in Spain, and the presence of radioactive iodine-129 near fuel processing facilities. Furthermore, the site's location adjacent to the Savannah River, a major regional water source, presented a clear pathway for contaminants to migrate downstream, potentially impacting water quality for numerous communities and ecosystems. Consequently, recognizing these risks, the decommissioning of nuclear facilities and the environmental remediation of contaminated areas became imperative by the end of the 1980s.

In 1981, environmental monitoring disclosed the presence of trichloroethylene and tetrachloroethylene in groundwater near the M Area Settling Basin. These were non-radioactive solvents normally used by the dry cleaning industry but employed at the SRP as a degreaser. The basin had overflowed and contaminated the surrounding area, including Lost Lake, a wetland in a shallow depression. The organic chemicals were removed from the groundwater by pumping and treating the water. Heavy sludge and contaminated soil was dumped in the M Area Settling Basin, which was then capped with dense clay and covered with soil and grass. The process was completed in 1991 at a cost of $5.8 million (equivalent to $ million in ) from the Resource Conservation and Recovery Act (RCRA). In the process, Lost Lake was drained, the vegetation and that of 50 meters around was pulled up and burned, and the soil was replaced with clean soil. About 150 plants of ten different species were planted around Lost Lake, which was allowed to refill, and aquatic vegetation was planted. Between 1993 and 1996, scientists from the SREL, Savannah River Forest Station and Westinghouse observed the amphibians gradually recolonising Lost lake; eventually 15 of the 16 species originally present returned.

An Effluent Treatment Facility began operations in October 1988 to treat low-level radioactive waste water from the F and H Area Separations facilities. In 1989, the SRS was included on the National Priorities List and became regulated by the Environmental Protection Agency (EPA). Two years later, the mixed waste management facility became the first site facility to be closed and certified under the provisions of RCRA. L Reactor and M Area settling basin were shut down. Construction began on a Consolidated Incineration Facility in 1993. In 1996, DWPF introduced radioactive material into a borosilicate glass vitrification process. F Canyon was restarted and began stabilizing nuclear materials. The first high-level radioactive waste tanks were closed in 1997, and in 2000, the K-Reactor building was converted to the K Area Materials Storage Facility. Transuranic waste was contained and sent by truck and by rail to the DOE's Waste Isolation Pilot Plant (WIPP) Project in New Mexico, with the first shipments beginning in 2001. The F Canyon and FB Line facilities completed their last production run in 2002. M Area closure was completed in 2010, with the P and R Areas following in 2011.

Former MOX fuel fabrication facility

In September 2000, the United States and Russia signed the Plutonium Management and Disposition Agreement. This agreement initially called for each country to dispose of 34 metric tons of surplus weapon-grade plutonium by converting it into mixed oxide fuel (MOX fuel) that can be irradiated once through in commercial nuclear power reactors or, in the case of the United States, to immobilize part of its plutonium in glass or ceramic, as well, for direct disposal in a deep geological repository. In the United States, both strategies would convert the surplus weapon-grade plutonium into forms that would meet the ''"Spent Fuel Standard"'' introduced by the National Academy of Sciences in 1994, meaning that the plutonium would be difficult to acquire and rendered unattractive for weapons use.

The Savannah River Site was selected in 2007, with operations slated to begin in 2016, as the location of three new plutonium facilities for: MOX fuel fabrication; pit disassembly and conversion; and plutonium immobilization. On 1 August 2007, construction officially began on the $4.86 billion MOX facility. Following startup testing, the facility expected a disposition rate of up to 3.5 tons of plutonium oxide each year.

In 2010, the agreement was amended to change the initially agreed disposition methods. Russia would instead use the MOX fuel route in its fast-neutron reactors BN-600 and BN-800. The Russian Federation met its obligations, completed its processing facility and commenced processing of plutonium into MOX fuel with experimental quantities produced in 2014 for a cost of about $200 million (equivalent to $ million in ), reaching industrial capacity in 2015. The United States decided to fully committing itself to the MOX fuel route.

The cost of the Savannah River Site MOX plant quickly escalated. In 2015, a report by the National Nuclear Security Administration (NNSA) estimated the total cost over a 20-year life cycle for the MOX plant to be $47 billion (equivalent to $ billion in ) if the annual funding cap was increased to $500 million or $110 billion if it were increased to $375 million. The Obama administration and Trump administration had proposed cancelling the project, but Congress continued to fund construction.

The Aiken Chamber of Commerce filed a lawsuit against the federal government claiming they have become a dumping ground for unprocessed weapons grade plutonium for the indefinite future and demanding previously agreed upon payment of contractual non-delivery fines. The federal government filed for dismissal and it was granted in February 2017. In 2018, the state of South Carolina similarly sued the federal government over the termination of the project, arguing that the DOE had not prepared an environmental impact statement concerning the long-term storage of plutonium in the state and additionally that the government had failed to follow the statutory provisions concerning obtaining a waiver to cease construction on the facility. In January 2019, the Fourth Circuit Court of Appeals rejected South Carolina's suit for lack of standing; in October 2019, the U.S. Supreme Court rejected the state of South Carolina's petition of ''certiorari'', thereby allowing the lower court's ruling to stand and the federal government to terminate construction.

In May 2018, Energy Secretary Rick Perry informed Congress he had effectively ended the about 70% complete project. Perry stated that the cost of a dilute and dispose approach to the plutonium will cost less than half of the remaining lifecycle cost of the MOX plant program. In February 2019, the Nuclear Regulatory Commission (NRC) granted a request to terminate the plant's construction authorization.

Litigation

After six years of litigation over plutonium moved to the site, South Carolina Attorney General Alan Wilson announced on 31 August 2020 that the federal government agreed to pay the state $600 million. Wilson described this as "the single largest settlement in South Carolina's history". The federal government also agreed to remove the remaining 9.5 metric tons of plutonium stored at the site by 2037. At a town hall meeting at USC-Aiken on 20 August 2021, South Carolina Governor Henry McMaster led a discussion on how to spend $525 million of that amount.

Major facilities and operations

National security

Savannah River Plutonium Processing Facility

The unfinished MOX fuel fabrication facility is being repurposed to construct the Savannah River Plutonium Processing Facility (SRPPF) to produce at least 50 war reserve plutonium pits per year at the Savannah River Site, with surge capacity to meet NNSA's requirement of 80 pits annually by 2030 following a two-site strategy with SRS producing annually no fewer than 50 pits and Los Alamos National Laboratory producing no fewer than 30 pits.

Tritium stockpile management

Tritium must be replenished continually because it decays exponentially at the rate of about 5.48% per year. The SRS tritium facilities are therefore operated to actively manage the US tritium stockpile by recycling tritium from decommissioned warheads and by extracting tritium from target rods irradiated originally at SRS but later in the commercial nuclear power reactors operated by the Tennessee Valley Authority. Several production scale separation methods of tritium from other hydrogen isotopes were used at SRS. These methods include thermal diffusion (1957–1986), fractional absorption (1964–1968), cryogenic distillation (1967–2004) and, since 1994, thermal cycling absorption process (TCAP), a metal hydride based hydrogen isotope separation system.

Increasingly stringent safety and environmental requirements required to replace the facilities in operation since 1955 to maintaining tritium productivity. The decision was taken in the early 1980s to build a new tritium handling facility, the Replacement Tritium Facility (RTF). This efficient TCAP process, invented in 1980s at SRS, was chosen chosen in 1984 as the isotope separation system for the new facility. Its construction began in 1987 and became operational on April 9, 1994, replacing completely the 1950s tritium handling facilities in 2004. The modernization of the tritium facilities at SRS continued by essentially expanding RTF into the Tritium Extraction Facility (TEF) at a cost of $507 million (equivalent to $ million in ) Construction commenced in July 2000, and the TEF commenced operations in 2006.

= Tritium recycling

=
One source of tritium is the recycling of tritium of nuclear weapons, many of which were dismantled due to post-Cold War limitations treaties and agreements. Canisters of tritium are routinely returned to the SRS for processing. Each contained three gases: tritium, deuterium, and helium-3, the decay product of tritium and a neutron poison. A 400 W laser is used to cut a tiny hole through which the heated gases escape. The gas mixture is then passed over a metal hydride bed to harvest the helium-3. The tritium and deuterium are then separated using the thermal cycling absorption process (TCAP).

= Tritium production

=
With the production reactors shut down, there was concern that the nuclear weapons stockpile would become inert through loss of tritium. One possibility was the NPR, but in November 1991 it was postponed for two years due to the end of the Cold War. The following year it was postponed to 1995, and ultimately was never built. The possibility of producing tritium using a linear accelerator, an idea that had already been rejected in 1952, was considered but never implemented.

File:Savannah River Site - Tritium Extraction Facility 001.jpg, Tritium Extraction Facility
File:Savannah River Site - Tritium Extraction Facility 002.jpg, Control room

Another source of tritium was required, and DOE turned to the Tennessee Valley Authority (TVA). Tritium producing burnable absorber rods (TPBARs) were sent to the TVA for irradiation in its commercial Watts Bar Nuclear Plant and Sequoyah Nuclear Plant and sent subsequently for processing to the TEF at SRS.

H Canyon nuclear materials disposition

H Canyon is the sole operational, industrial-scale, nuclear reprocessing facility in the United States. At the end of the Cold War, its mission shifted towards non proliferation and environmental remediation by processing and downblending weapon-grade nuclear materials, like high-enriched uranium or plutonium, for final disposition.

The spent fuel rods are dissolved in nitric acid and the chemical separation occurs in radiologically shielded facilities. It can also process spent nuclear fuel or "uranium liquid", also known as Target Residue Material, from third countries like for example, from the Chalk River Facilities in Canada, as part of the Global Threat Reduction Initiative launched in 2004 by the National Nuclear Security Administration to expand efforts similar to the Cooperative Threat Reduction program beyond the former Soviet Union.

Waste management and disposition

Since the early 1980s, DOE has been developing, constructing, and operating an integrated suite of facilities for the treatment and disposition of high-level radioactive waste that had been accumulating since 1951 in underground tanks within the F-Area and H-Area at the Savannah River Site. The Defense Waste Processing Facility immobilizes liquid radioactive waste into a stable glass matrix suitable for long-term containment and disposal in a future deep geological repository. A series of supporting facilities, built in the decades that followed, support the DWPF operations by enabling the removal, transfer, segregation, pretreatment, and handling of tank waste prior to and following vitrification. Additional facilities were built to manage and dispose the resulting secondary low-level radioactive waste (LLW) streams and liquid effluents generated during the vitrification process.

F-area and H-area tank farms

The production and processing of strategic materials has generated about of liquid radioactive waste that have been concentrated by evaporation to preserve tank space to a volume estimated, in November 2005, at . It is stored in 51 carbon-steel tanks, built between 1951 and 1981, and grouped into two tank farms in the F-area and H-area. Evaporation began at F Area in 1960, and H Area in 1963. Evaporator water, containing low levels of radioactivity, was discharged to the F and H Area seepage basins until in 1990, it was rerouted to the Saltstone Facility. , the tanks are being emptied and decommissioned under the regulatory oversight of the Nuclear Regulatory Commission.

The legacy nuclear waste consists of approximately of sludge, composed primarily of insoluble metal hyrdroxide solids that settled at the bottom of the tanks; and approximately of salt waste, which is composed of concentrated soluble salt solution ( supernate) and crystallized saltcake. This waste is being treated and further reduced in volume in the Salt Waste Processing Facility. The most radioactive part is sent to the Defense Waste Processing Facility for vitrification, while the remaining salt residues are grouted and sent to the Saltstone Disposal Facility for disposal.

File:2F Evaporator (50327016872).jpg, 2F Evaporator taken at F-Tank Farm
File:SDUs Z Area Aerials 3-28-23 (54439548358).jpg, Aerial view of the Saltstone Disposal facility

Salt Waste Processing Facility (SWPF)

The Salt Waste Processing Facility separates and concentrates highly radioactive caesium-137, strontium-90, and selected actinides from the less radioactive salt solutions removed from the liquid legacy nuclear waste stored in large underground double walled storage tanks located in F-area and H-area tank farms.

Initially estimated at $982.5 million in 2009 (equivalent to $ million in ), the SWPF cost escalated in 2014 to $2.3 billion (equivalent to $ billion in ). Operational since 2021, the SWPF use specific processes that have been developed at Oak Ridge National Laboratory and Argonne National Laboratory using annular centrifugal contactors. The concentrated waste is sent over, as a slurry, to the nearby Defense Waste Processing Facility for vitrification. The remainder decontaminated salt solution is mixed with fly ash, furnace slag, and Portland cement in the nearby Saltstone Production Facility. The resulting grout, which cures to a waste form known as saltstone, is pumped into disposal units at the Saltstone Disposal Facility.

Defense Waste Processing Facility (DWPF)

In the late 1960s, the Savannah River Laboratory began research to find a suitable solution for the management and disposal of liquid, highly radioactive waste generated at SRP. The first Savannah River waste was vitrified on a laboratory scale in 1972. By the mid-1970s, SRP began planning and designing America’s first vitrification plant to immobilize the high-level radioactive waste stored in the SRP waste tank farms in borosilicate glass. After evaluating other methods, DOE choose vitrification for the long term management option for SRP waste in 1982 and pursued the development the Defense Waste Processing Facility (DWPF). The highly radioactive slurry is mixed with glass-forming chemicals into a 65-t Joule-heated ceramic melter up to . The molten borosilicate glass is poured in canisters and solidifies in canisters, thereby immobilizing the waste for thousands of years. Each canister is in height and in diameter, with an empty weight of around . The process of filling a single canister typically requires one day, after which the total weight increases to approximately .

DWPF is the only operating radioactive waste vitrification plant in the United States and the world's largest. Its construction began on 4 November 1983, and the facility commenced operation in March 1996. In 1987, DOE projected the DWPF to cost an estimated $1.2 billion (equivalent to $ billion in ) and to begin vitrifying waste in September 1989. In January 1992, costs escalated up to $2.1 billion (equivalent to $ billion in ) and the start of vitrification operations was scheduled for June 1994.

File:DWPF S Area Aerial 3-28-23 (54439669285).jpg, Aerial view of the Defense Waste Processing Facility (DWPF)
File:DWPF Canisters (35842794646).jpg, Borosilicate glass is mixed with the waste, heated in a melted until molten, and poured into stainless steel canisters to harden.
File:DWPF Canisters (35074413643).jpg, Each canister, tall and in diameter, weighing about , is stored at SRS Glass Waste Storage Building until a permanent repository is completed.

To complete its vitrification of the legacy nuclear waste, DWPF is projected to produce over 8,000 canisters. The canisters containing vitrified high-level nuclear waste are currently stored in two Glass Waste Storage Buildings (GWSB).

Saltstone Disposal Facility (SDF)

The development of saltstone, a cement-based waste form for disposal of low-level radioactive salt waste, primarily sodium nitrate, started at SRS in the 1980s. The Saltstone Facility has been operational in the Z-Area since 1990. It is located in the SRS Z-Area and is approximately 10 kilometers (6.2 miles) from the main site. The Saltstone Facility consist of the Saltstone Production Facility (SPF) and the Saltstone Disposal Facility (SDF). SPF receives and treats the salt solution to produce saltstone grout by mixing it with fly ash, furnace slag, and Portland cement. The saltstone grout form is pumped to large pre-constructed concrete structures serving as final disposal units, known as Saltstone Disposal Units.

E Area Low-level Waste Facility (ELLWF)

The ELLWF uses approximately 100 acres for active disposal operations. Most low-level radioactive waste disposed at the ELLWF is generated at various SRS facilities, although ELLWF also receives waste from the U.S. Naval Reactors program.Assessment of Savannah River Site Radioactive Waste Disposal Facilities
, September 2016

File:E Area Burial Ground Aerial 3-28-23 (54439472179).jpg, Aerial view of the E Area Burial Ground
File:E Area Burial Grounds Aerial 2-14-23 (54439650310).jpg, Disposition of low-level waste in the E Area
File:Savannah E Site (7507794862).jpg, Slit trenches for the disposition of low-level waste

Effluent Treatment Facility (ETF)

The Effluent Treatment Facility (ETF) began operations in October 1988 to treat low-level radioactive waste water from the F and H Area Separations facilities. It treats low-level radioactive water originating from the separation and waste management facilities, associated laboratories, the Savannah River National Laboratory, and environmental cleanup activities. The facility removes chemical contaminants (heavy metals, organics, corrosives) and radiological contaminants (like caesium) before releasing the treated water into Upper Three Runs Creek, which flows into the Savannah River.

Constructed between January 1987 and its operational startup in October 1988 at a cost of $55 million, the ETF was engineered to meet environmental regulations under RCRA and NPDES considering that Savannah River downstream from SRS is utilized for drinking water. Its design adapted existing wastewater treatment technologies for radioactive use. The facility has a design processing capacity of 100,000 to 250,000 gallons per day and a maximum permitted capacity of 430,000 gallons per day.

Isotope production program

SRS continues to play a strategic role in recovering rare isotopes like plutonium-244 and heavy curium from targets, irradiated from the 1960s through the 1980s in its production reactors, for fundamental research and nuclear nonproliferation research. The 65 unprocessed targets irradiated for the production of californium-252 were kept in storage at SRS for decades until their strategic value was finally recognized. These targets contain the world's supply of unseparated plutonium-244 and other heavy actinides. In 2001, this unseparated plutonium-244 was recognized as a National Resource material. The total inventory is estimated to be of about 20 grams of plutonium-244 among the 65 targets. This valuable feedstock for producing new heavier actinides are economically irreplaceable. Since 2015, the DOE is funding a program to recover the plutonium-244 and other transplutonium elements.

SRS is also the main supplier of helium-3, a highly coveted isotope of helium for its significant role in neutron detection applications, specially following the September 11 terror attacks, and fundamental research. Since 2001, annual demand has far exceeded annual production in the United States and Russia, leading to a reduction of the helium-3 stockpile worldwide. Helium-3 is a valuable commodity, and sold for between $2,000 and $2,500 per liter in 2020 (equivalent to $ to $ in ).

To maintain the tritium stockpile, helium-3 needs to be extracted on a daily basis and stored in pressurized cylinders at SRS.To further purify it and remove trace amounts of tritium and other impurities, these cylinders are shipped to a nuclear facility of Linde plc in New Jersey. As of February 2011, helium-3 inventory at SRS was estimated to be around 31,000 liters, with an additional yearly supply of 8,000 to 10,000 liters harvested from the tritium stockpile.

Operations and contract management

Westinghouse replaces DuPont

The 1979 Iran hostage crisis gave rise to concerns about the Islamic terrorism. DuPont had always been in charge of all aspects of Savannah River Plant operations, including security, but baulked at taking special measures to confront the terrorist threat. The DOE then engaged the services of Wackenhut Services Incorporated (WSI) to provide security support services at the SRP. Security was tightened around the reactors, separations area and fuel manufacturing area. The terms of the contract with DuPont no longer satisfied Congress. In particular, the contract held that DuPont would not be held liable for damages in the event of an accident or litigation. DuPont felt that this was only fair, as the firm was operating the plant on a non-profit basis, and had originally accepted the contract only out of a sense of corporate patriotism. In 1987, DuPont notified DOE that it would not continue to operate and manage the site when the latest extension expired in 1989.

DOE put the contract out to tender. The Savannah River Plant would now be operated for a profit of between $26 and $40 million (equivalent to between $ and $ million in ). There were two bids: one from Westinghouse Electric with Bechtel; and one from a consortium headed by Martin Marietta with EG&G and United Engineers and Constructors. On 8 September 1988, DOE announced that the contract had been awarded to the Westinghouse Savannah River Company, a subsidiary of Westinghouse Electric created to run the SRP. The indemnity issue had been resolved by the Price-Anderson Act, which provided liability protection for the operator. Westinghouse assumed control of the SRP on 1 April 1989, and one of its first actions was to rename the facility the "Savannah River Site". All existing employees were guaranteed continued employment, and the work force grew to 22,800 and the budget to $2.2 billion in 1991 (equivalent to $ billion in ), twice what it had been in 1989.

At this point, all the reactors were still down for maintenance. On the one hand, there was public pressure not to restart them; on the other, there was a pressing need for tritium. A Westinghouse safety review in April 1989 found that K, L and P reactors could all be restarted, but attention was focused on K Reactor. In May 1990, Energy Secretary James D. Watkins announced that K Reactor would be restarted in December, followed by P Reactor in March 1991 and L Reactor in September 1991. South Carolina law now required that water discharged into the river be no warmer than . To meet this requirement, a cooling tower was built at a cost of $90 million (equivalent to $ billion in ). In December 1991, one of K Reactor's heat exchangers sprung a leak and of tritiated water was released into the river. Public utilities downstream closed their inputs until the contaminated water had passed. K Reactor went critical on 8 June 1992, but only for a test run. P Reactor was shut down permanently in February 1991. L Reactor, which had been on standby, was ordered to be shut down without the possibility of restart in April 1993, and in November 1993, Energy Secretary Hazel R. O'Leary announced that K Reactor would not be restarted.

Contract management

In 1995, DOE announced that it would seek an open selection process for the SRS contract, which was up for renewal. However, the only bid received was from the Westinghouse Savannah River Company. In addition to its partner Bechtel, Westinghouse now also brought in Babcock & Wilcox and British Nuclear Fuels. In a visit in 2004, Secretary of Energy Spencer Abraham designated the Savannah River National Laboratory (SRNL), one of twelve DOE national laboratories.

Management of the SRS was to be bid in 2006, but the DOE extended the contract with the existing partners for 18 months to June 2008. DOE decided to split the contract into two new separate contracts, i.e. the M&O Contract and the Liquid Waste Contract to be awarded before June 2008. Responding to the DOE RFP, the Savannah River Nuclear Solutions (SRNS), LLC – a Fluor partnership with Honeywell, and Huntington Ingalls Industries (formerly part of Northrop Grumman) – submitted a proposal in June 2007 for the new M&O Contract. A team led by URS and including many of the WSRC partners also submitted a proposal. On 9 January 2008, it was announced that SRNS LLC had won the new contract, with a 90-day transition period to start 24 January 2008. Savannah River Remediation (SRR) was awarded the contract for the Liquid Waste Operations.

In 2012, the M&O contract was extended by 38 months to 2016. In 2021, DOE awarded the new Integrated Mission Completion Contract to Savannah River Mission Completion, an LLC comprising BWX Technologies, Amentum's AECOM, and Fluor. Transition from the Liquid Waste Operations contract to the Integrated Mission Completion Contract was completed in early 2022. As of 2020, the economic impact of SRS was estimated to be $2.2 billion per year (equivalent to $ billion in ) in the surrounding region.

Notes

References

Sources

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External links

* '' Building Bombs'', a 1991 documentary film by Atlanta filmmakers Mark Mori and Susan J. Robinson
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