by Frank von Hippel
The U.S. government's fiscal year 2018 of began on 1 October but the Senate and House Armed Services Committees only completed on 9 November 2017 their work on the policy framework relating to military activities in the form of a Conference Report on the Fiscal Year (FY) 2018, National Defense Authorization Act (NDAA).
Three elements relating to fissile materials are discussed here:
- The development of low-enriched uranium (LEU) fuel for naval reactors;
- The disposition of excess weapons plutonium, and
- The reestablishment of a U.S. capability to make plutonium "pits" for nuclear weapons.
Development of LEU fuel for naval reactors. The U.S. nuclear navy accounts for about one third of the global consumptive use of highly-enriched uranium. During the past few years, some members of the House of Representatives have been trying to launch a program to develop LEU fuel. Other members have insisted that the funding for such an effort should come from the budget of the National Nuclear Security Administration's (NNSA's) nonproliferation program rather than from its budget for naval reactor R&D. For the third year in a row, the NDAA authorizes $5 million for the development of LEU fuel for naval reactors. It authorizes an additional $30 million if the Secretaries of Navy and Energy submit a required joint determination to proceed with the program.
Technically, NNSA's Office of Naval Reactors agrees that it should be possible to convert U.S. aircraft carriers to LEU fuel but believes that the LEU fuel design it is considering "is unlikely to enable conversion of current life-of-ship submarine reactors to LEU." The problem is that an LEU lifetime core would be larger than an HEU lifetime core. To clarify the issue, the Conference Report (Section 3115) requires "a report on the cost and timeline required to assess the feasibility, costs, and requirements for a design of the Virginia-class replacement nuclear attack submarine that would allow for the use of a low-enriched uranium fueled reactor, if technically feasible, without changing the diameter of the submarine."
Disposition of excess weapons plutonium. Under the Russia-U.S. Plutonium Management and Disposition Agreement of 2000, the two countries committed to dispose of 34 tons of excess weapons plutonium each - enough for about 10,000 nuclear warheads. The U.S. committed to dispose of 25 tons of its plutonium in mixed-oxide (MOX) uranium-plutonium fuel for U.S. power reactors. The G.W. Bush Administration increased that to the full 34 tons. However, the estimated cost for constructing the MOX Fuel Fabrication Facility at the Department of Energy's Savannah River Site in South Carolina, where much of the plutonium had originally been produced and separated, grew from $4.8 billion in 2007, for a completion date in 2016, to $17.2 billion in 2016 for a completion date in 2048. The Obama Administration declared that the project was "unaffordable" and proposed as an alternative to "dilute and dispose" of the plutonium in the Department of Energy's Waste Isolation Pilot Project (WIPP), a deep mine in a salt bed under New Mexico. This change, along with U.S. sanctions relating to Russia's incursions in Ukraine and the presence of U.S. troops in Eastern Europe, caused Russia to suspend its participation in the agreement.
The Trump Administration also favors dilute and dispose because of its lower cost. The Congressional delegation of South Carolina has led a so-far-successful congressional struggle to keep the MOX project on life support, however, and Congress has imposed a number of requirements before it will accept the dilute and disposal alternative (Section 3121). These include that:
- The cost of the dilute and dispose option "be less than approximately half of the estimated remaining lifecycle cost of the mixed-oxide fuel program;"
- The Secretary of Energy must provide "the details of any statutory or regulatory changes necessary to complete the option." (The federal and state regulatory issues that must be dealt with to assure that WIPP, which was originally designed for transuranic waste can physically and legally accommodate an order of magnitude more plutonium than originally envisioned were recently reviewed by the Government Accountability Office); and
- A "sustainable future" is established for the Savannah River Site, which, since the end of plutonium production there in 1988, has been primarily a tritium processing and radioactive cleanup site at a cost of about $1 billion per year for cleanup with the end date currently projected for 2065.
Plutonium pit production. The U.S. has about 4,000 "operational" nuclear warheads plus a reserve of plutonium pits from about as many more dismantled nuclear warheads. These pits, mostly manufactured in the 1970s and 1980s, show virtually no signs of degradation and have estimated lifetimes of one hundred years or more. Nevertheless, Congress, in the Defense Authorization Act for FY2015 required the establishment of a capability to produce 80 pits per year by 2027 (50 U.S.C. 2538a). It appears that this requirement was driven primarily by NNSA's interest in developing new warheads that will be interoperable between land- and sea-based strategic missiles.
Industrial-scale pit production of pits at the Rocky Flats Plant outside Denver, Colorado was shut down by environmental violations at the end of the Cold War. In 1996, it was decided that a small pit production capacity would be established at the Los Alamos National Laboratory, where pit production R&D has been conducted since the World War II Manhattan Project. At the time, no construction was thought necessary to establish pit production capacity in the large Plutonium Facility at Los Alamos.
The Plutonium Facility is 40 years old, however, and was not designed to withstand a seismic risk that has been revised significantly upward since 1996. An extensive program of reinvestment is underway, with the goal of extending the life of the facility to 2039. The cost of projects to replace buildings housing supporting analytical chemistry and waste management capabilities grew in cost to the point where they were cancelled.
A leaked summary of an NNSA "Assessment of Alternatives" indicates that the completed but not yet equipped MOX fuel production building on the Savannah River Site is being considered as an alternative to Los Alamos for pit production. This would solve the problem of a "sustainable future" for SRS. Section 3141 of the FY2018 NDAA contains an unrealistic "poison pill" amendment introduced by advocates of Los Alamos requiring that, if NNSA cannot make a decision on Savannah River within 3 months, pit production must stay at Los Alamos. Such requirements are not written in stone, however.