Frank N. von Hippel
The U.S. Department of Energy published its Congressional Budget Request for Fiscal Year 2021. The items below appear in Volume 1, which covers nuclear weapon activities, defense nuclear nonproliferation and naval reactors, and Volume 3, Part 2, which includes nuclear power.
Plutonium pit production (Volume 1, pp. 162, 193-205). In its 2018 Nuclear Posture Review, the Trump Administration proposed that the US establish a capacity to produce at least 80 plutonium pits for nuclear weapons per year by 2030. Congress has agreed and appropriated $407 million in Fiscal Year (FY) 2019 and $798 million in FY2020. In the FY2021 budget. DOE proposes an increase to $1.369 billion.
Plutonium pits are the cores of the fission triggers of modern thermonuclear weapons. The US has not had an industrial-scale pit production capacity since the end of the Cold War. The capability to produce pits was preserved at the Los Alamos National Laboratory, which produced 29 "war-reserve" pits from 2007 through 2012. This low capacity has not been considered a serious problem until recently since a JASON Group review of DOE work concluded that "Most primary types have credible minimum lifetimes in excess of 100 years as regards aging of plutonium". The oldest pit currently in the US operational stockpile is approximately 40 years old.
The only immediate need for pits is associated with a proposal to replace the W78 warhead on the US Minuteman III intercontinental ballistic missile with a new warhead, the W87-1, that will contain insensitive high explosive (IHE). All US warheads are already "one-point safe," i.e. if the explosive around the pit were detonated at one point by, for example, a bullet, there would be no significant nuclear yield. The IHE would reduce the probability of a plutonium dispersal incident, however.
Each of the 400 Minuteman III missiles carries one warhead. Half the deployed warheads are W87s, which already contain IHE. There reportedly are 540 W87s - enough to replace the W78s but the DOD-DOE Nuclear Weapons Council decided to newly produce a variant of the W87, the W87-1, to replace the W78. The usual logic is to have two types of warheads available per missile in case a problem develops with one of them but the W87-1 would have the same fission "primary" as the W87, the component upon which concerns about reliability usually focus.
The W87-1 is also being considered as a replacement for the W88, one of the two warheads on the Trident II submarine-launched ballistic missile. The Trump Administration also has proposed to begin designing another new warhead for the Trident II. The new warhead is to be called the W93. Neither of the two warheads currently carried by Trident II, the W76 and the W88, contains IHE. Replacing them and the W78 would complete the transition of the US warhead stockpile to IHE. In the past, however, the navy has rejected replacing the W76 and the W88 with IHE-containing warheads as an unnecessary costly project because, unlike the Air Force, which has had nuclear-armed bombers crash and burn, the navy has never had a plutonium dispersal accident. Nevertheless, the nuclear weapon laboratories have persisted in pushing for three decades for replacement warheads containing IHE as the only rationale for designing new warheads and have finally found a friendly administration. Indeed, the Trump Administration proposes to increase the weapons budget at Los Alamos by 50% or $1 billion to $2.9 billion in FY2021. Lawrence Livermore has received a 33 percent boost in its own weapons budget since FY2019 to $1.8 billion.
NNSA plans to make the pits at two locations: Los Alamos National Laboratory's Plutonium Facility-4 (PF-4), whose production capacity would be increased to 30 pits/year, and the DOE's Savannah River Site (SRS) in South Carolina where a new facility would have a design capacity of 50 pits/year. At SRS, an abandoned multi-billion dollar building that was originally built to turn excess US plutonium into mixed oxide (MOX, uranium-plutonium) fuel for US power reactors would be adapted for pit production.
DOE estimates the cost for the Savannah River plutonium production facility as $4.6 billion and the cost of 'plutonium modernization' at Los Alamos at $5.4 billion for FY21-25. There is no estimate yet for the total cost of reaching a production capacity of 30 pits/year at Los Alamos. Given all the safety issues that have been encountered at Los Alamos' plutonium facility, however, these costs are likely to grow as the schedules slip.
Dilution and Disposal of Excess Plutonium (Volume 1, pp. 658-664). The Trump Administration has committed to the Obama Administration's proposal to blend down US excess plutonium and dispose of it in the Waste Isolation Pilot Plant in New Mexico. The FY21 budget request is for about $0.15 billion and projects a total of $0.62-0.71 billion to set up for processing 1.5 tons of plutonium per year at the Savannah River Site.
DOE's current plan for disposal of its 57.1 tons excess plutonium is to start with up to 6 tons of plutonium that is already in oxide form, dilute it with a mix of chemicals from which it would be difficult to recover, and dispose of the mix in the Waste Isolation Pilot Project (WIPP), a deep repository in a salt bed in New Mexico. The excess plutonium that is already in oxide form is stored in the former K-reactor building at the DOE's Savannah River Site (SRS) in South Carolina. Disposal of this plutonium is being prioritized because of an overdue commitment to the State of South Carolina that the plutonium would be removed from the state. The plan is to carry out the dilution operation at a rate of 1.5 tons per year in three gloveboxes that are to be installed in the K-reactor building. Disposition operations would begin in 2028 at an estimated annual cost of $58.3 million. After the disposal of this plutonium, there is an additional 43.8 tons of excess plutonium in pits and other metal forms that would have to be converted to oxide before dilution. (The remaining 7 tons of excess plutonium is in spent fuel.) The plan has been to do that conversion at Los Alamos National Laboratory's troubled PF-4 facility (see item on pit production above) but Congress' Government Accountability Office has questioned the credibility of expanding both pit production and plutonium oxidization in the same aging facility.
Versatile test reactor (VTR) (Volume 3, pp. 104-117). DOE's Office of Nuclear Energy has requested $295 million (up from $65 million in FY2020) to build a liquid-sodium-cooled test reactor at the Idaho National Lab (INL). The design would be based on INL's Experimental Breeder Reactor II, which the Clinton Administration shut down in 1994 for lack of mission. DOE's initial cost estimate for the VTR is $3 to $6 billion and its goal is to complete the reactor during 2026-30.
The need for the VTR is questionable. The $295 million requested in FY2021 is a quarter of DOE's total proposed budget for nuclear energy research and development. At a constant budget level, that share would have to increase to about half even if the cost estimate does not increase. In fact, the budget appears to anticipate a zero-sum competition between the VTR and the other parts of DOE's budget for nuclear energy, proposing elimination of many programs, including programs supportive of the development of the new types of power reactors that were used to justify the VTR.
Development of LEU fuel for naval reactors (Volume 1, p. 643). After at first welcoming Congressional interest in the development of LEU fuel for its naval reactors, DOE's Office of Naval Reactors is resisting. Congress has funded this program every year starting in FY2016. DOE proposes to zero out that effort.
In 1994 and again in 2012, Congress asked the Office of Naval Reactors (ONR) about the feasibility of designing future US naval-propulsion reactors to use low-enriched instead of weapon-grade uranium. The response in 1995 was that this would require the office to give up its long-term goal of equipping US nuclear submarines with lifetime cores, a goal it believes that it has achieved with the Virginia-class attack submarines that are currently being produced and the Columbia-class ballistic-missile submarines that are currently being designed. In 2014, ONR suggested that the problem might be mitigated by the development of higher-density fuels and, in 2016, it proposed an R&D program to develop and test such fuels.
Subsequently, the navy turned against the effort, however, and, in 2018, the Secretaries of Energy and the Navy wrote a joint letter to Congress stating that "we have jointly determined that the United States should not pursue Research and Development (R&D) of an advanced naval nuclear fuel system based on Low-Enriched Uranium (LEU)". Congressional supporters of LEU fuel development responded by shifting funding to a line item for "nonproliferation fuels development" in the NNSA's office of Defense Nuclear Nonproliferation, which has tasked three of DOE's civilian laboratories (Argonne, Oak Ridge and Idaho National Laboratories) to do the research. In FY2020, Congress funded the program at a level of $15 million dollars, but the Trump Administration has asked for zero funding for FY2021.
More DOE Funding for Centrus corporation? (Volume 1, pp. 585-592, 604-612). The Trump Administration proposes to fund the development of domestic enrichment out of nonproliferation funds.
In DOE's FY2020 budget request, the Office of Nuclear Energy proposed a $115 million contract with Centrus corporation to install 16 centrifuges at the DOE's Piketon facility to demonstrate the production of high-assay low-enriched uranium (HALEU) for some of the small modular power reactors that the Office is promoting. This caused controversy since DOE signed the contract without Congressional authorization and the funds were obtained in part by cutting support for university research in nuclear engineering. Also, URENCO-USA has expressed a willingness to produce HALEU at a tiny fraction of the cost of the Centrus project (see the earlier IPFM post). In the FY2021 budget request, the Office of Nuclear Energy promises not to spend beyond the $115 million contract (Volume 3-2, p. 49) but a $71 million increase has appeared in the Defense Nonproliferation program part of DOE's budget, specifically in the "material management and minimization" program that has in the past been used to convert research reactors fueled with highly-enriched uranium (HEU) to LEU and to retrieve HEU and plutonium from around the world. The justification for the $71 million increase is that it
"supports [Defense Nuclear Nonproliferation's] contribution to the Office of Defense Program's (DP) domestic uranium enrichment project, which includes a high-assay low-enriched uranium (LEU) requirement [and for other programs]."
The share of the $71 million going to the "enrichment project" and whether that project is Centrus is not specified. In the meantime, Defense Programs, whose program Defense Nuclear Nonproliferation claims to be supporting, is still considering options for its future needs of enriched uranium to fuel US tritium production and naval reactors after 2041 and 2060 respectively (Volume 1, pp. 180-81).