October 19, 2000



The Honorable Bill Richardson

Secretary of Energy

U.S. Department of Energy

1000 Independence Ave, SW

Washington, DC 20585



Dear Secretary Richardson:


We are writing to you concerning the Surplus Plutonium Disposition Final Environmental Impact Statement (EIS) and the associated Record of Decision (ROD) issued by the Department of Energy (DOE).


Since the ROD was issued on January 4 of this year, significant new information has come to light regarding serious safety concerns at the four nuclear reactors that DOE has selected to use mixed-oxide (MOX) fuel derived from surplus weapons-grade plutonium. Consequently, as required by Council on Environmental Quality (CEQ) and DOE National Environmental Policy Act (NEPA) implementing regulations (40 CFR 1502.9(c) and 10 CFR 1021.314, respectively), we request that DOE prepare a new supplemental environmental impact statement that analyzes this "significant new ... information relevant to environmental concerns and bearing on the proposed action or its impacts."


Pending completion of the additional documents that are required under NEPA, we also request that DOE suspend its contract with Duke Cogema Stone & Webster (DCS), the consortium chosen to fabricate and irradiate MOX fuel in the U.S. Until the serious safety concerns that have emerged at the nuclear plants designated for MOX use are fully resolved to the satisfaction of all stakeholders, the ability of DCS to carry out the terms of the contract will remain in doubt.


The significant new information in question is contained in a technical report that was issued by the Nuclear Regulatory Commission (NRC) in April, Assessment of the DCH [Direct Containment Heating] Issue for Plants with Ice Condenser Containments (NUREG/CR-6427). [1] This report evaluates the vulnerability of U.S. nuclear plants with ice condenser containments to early containment failure in the event of a severe accident, where early containment failure is defined as that occurring within a few hours of initiation of core melt, and before effective evacuation of the public can take place. The study shows that "ice condenser plants are substantially more sensitive to early containment failure than PWRs [pressurized-water reactors] with large dry or subatmospheric containments" (Executive Summary, p. xix).


As you know, the four reactors that Duke has designated to irradiate MOX fuel, McGuire 1&2 and Catawba 1&2, have ice condenser containments. NRC's new findings are of particular concern in view of the potential use of MOX fuel in Duke's ice condenser plants. The public health consequences of a severe reactor accident with containment failure and core dispersal will be significantly increased if MOX fuel is used, because of the greater concentrations of plutonium and other actinides in MOX cores compared to LEU cores. [2] This is exactly the type of accident to which Catawba and McGuire are particularly susceptible. Therefore, it is incumbent upon DOE to thoroughly analyze the risks to the public associated with the plutonium disposition program, using the best available data. Anything less would be an abrogation of DOE's responsibility to the public and a violation of its statutory requirements under NEPA.


NUREG/CR-6427 concludes that "ice condenser plants are at least two orders of magnitude more vulnerable to early containment failure than other U.S. PWRs." This is because ice condenser containment structures have, on average, only one-half the ultimate failure pressure and containment volume of other PWR containments, and cannot withstand credible hydrogen combustion events.


The risk of early containment failure is highest in the event of an accident occurring during a station blackout, since in that case the AC-powered hydrogen control system (glow plug igniters) would be disabled. In particular, the NRC report finds, in the event of an accident with station blackout, core melt and breach of the reactor vessel at high pressure, that the probability of early containment failure is 100% for Catawba and 98% for McGuire. Early containment failure is therefore a virtual certainty if this accident scenario were to occur at one of Duke's ice condenser units. The total containment failure probability remains high even when all accidents are considered, including those in which AC power to the hydrogen control systems is maintained. Overall, the NRC report calculated that McGuire has a probability of early containment failure given core damage of 13.9%, exceeding NRC's screening criterion of 10%. [3] Based on these findings, NRC staff has recommended that new regulatory requirements for ice condenser plants be considered. [4]


NRC's new analysis of ice condenser containment failure illustrates the weaknesses of the analyses carried out by Duke for the McGuire and Catawba Individual Plant Examinations (IPEs). In particular, NRC's estimate of the McGuire early containment failure probability is seven times greater than Duke's own estimate of 2%. However, DOE relied heavily on Duke's questionable IPE accident probability data in its reactor accident analysis in the Surplus Plutonium Disposition Final EIS. Therefore, the findings contained in NUREG/CR-6427 clearly constitute "significant new information relevant to environmental concerns," requiring DOE to perform a new supplemental EIS under its NEPA implementing regulations.


We note that in the ROD for the Surplus Plutonium Disposition EIS, DOE states that "NRC has not considered it necessary to restrict operation of ... reactors in the United States that use ice condenser containments." It also states that safety issues associated with MOX use in ice condenser plants "will continue to be evaluated," referring to comprehensive safety reviews to be performed by NRC. NUREG/CR-6427 is an example of such a comprehensive safety review, and its findings have a direct bearing on the environmental impact of DOE's plutonium disposition program. It is therefore DOE's obligation to analyze this new information in a supplemental EIS and to suspend the MOX contract with DCS, which was let on the basis of outdated safety information.


We look forward to receiving your prompt reply to the requests stated above.







Edwin S. Lyman, PhD

Scientific Director




Eldon V.C. Greenberg

Garvey, Schubert and Barer




cc: Laura Holgate, DOE/NNSA

[1] M. Pilch, K. Bergeron and J. Gregory, Assessment of the DCH Issue for Plants with Ice Condenser Containments, NUREG/CR-6427, SAND99-2553 (Albuquerque, NM: Sandia National Laboratories, April 2000).

[2] Edwin S. Lyman, "Public Health Consequences of Substituting Mixed-Oxide for Uranium Fuel in Light-Water Reactors," to appear in the journal Science and Global Security.

[3] It should be noted that this result applies to core damage caused by internal events only. External events, such as earthquakes, floods and tornadoes, are associated with a substantially higher probability of station blackout than internal events. Therefore, if external events are also considered, the fraction of core damage events culminating in early containment failure will be significantly higher than this value.

[4] U.S. Nuclear Regulatory Commission, Status Report on Study of Risk-Informed Changes to the Technical Requirements of 10 CFR Part 50 (Option 3) and Recommendations on Risk-Informed Changes to 10 CFR 50.44 (Combustible Gas Control), SECY-00-0198, September 14, 2000.



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