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Background Paper

January 21, 1999


Dr. Lyman’s work indicates that there is a need for a full licensing review by the Nuclear Regulatory Commission (the "NRC") before any utility is permitted to use mixed oxide ("MOX") fuel in its reactors. The need for such review arises in connection with proposals to burn lead test assemblies ("LTAs"), partial core loads and full core loads.

(1) Burning LTAs in Commercial Reactors: The Need for a License Amendment

Previously, the industry has suggested that, under 10 C.F.R. 50.59, it would be possible to proceed without a license amendment to burn LTAs in civil reactors. Section 50.59(a)(1) allows license holders to "make changes in the facility as described in the safety analysis report ...[or] conduct tests or experiments not described in the safety analysis report, without prior Commission approval, unless the proposed change, test or experiment involves a change in the technical specifications incorporated in the license or an unreviewed safety question." Since the "changes" associated with MOX would not have been described in the Final Safety Analysis Report (the "FSAR"), [1] the industry's ability to invoke Section 50.59 hinges on whether there are "unreviewed safety questions" or changes to the "technical specifications". [2]

The industry would presumably argue that all MOX risks are bounded by the existing FSAR, and so there are no unreviewed safety questions. It contemplates preparing a Section 50.59 Safety Analysis Report which would define the number of LTAs to be inserted; list any "new features" of the LTAs; and examine the impact of each new feature on FSAR events. The goal of this exercise would be to demonstrate that MOX events fall "within the envelope" of existing accident analyses. The industry also contemplates preparing a "Section 50.46 Deviation Report" to demonstrate that MOX fuel will not significantly impact emergency core cooling system ("ECCS") acceptance criteria.

Dr. Lyman’s work casts doubt on the ability of the industry to make a compelling case that there are no unreviewed safety questions. Certainly, therefore, the NRC ought not to accept the proposition that proceeding under Section 50.59 is permissible without substantial, additional analysis. If Section 50.59 cannot be successfully invoked by the industry, then a license amendment, under the procedures specified at 10 C.F.R. 50.90-50.92, would be required for LTA testing. See 10 C.F.R. 50.59(c). [3]

(2) Burning Partial or Full Core Loads

(a) The Need for a License Amendment -- There is essentially no question that a license amendment under 10 C.F.R. Part 50 will be required to allow commercial power plants to burn partial and/or full core loads of MOX fuel. See 10 C.F.R. 50.90-50.92. This is so because the technical specifications describing fuel elements comprising reactor core must be revised. In the five cases where MOX has previously been permitted on experimental basis (San Onofre, Big Rock Point, Ginna, Quad Cities-1 and Dresden-1), the licensee applied for and received a license amendment. [4]

In connection with any license amendment, a key question will be whether the Commission staff can or will make a "no significant hazards determination" under 10 C.F.R. 50.92. Whether a no significant hazards determination can be made turns upon whether operation of the facility under the amendment would:

(1) Involve a significant increase in the probability or consequences of an accident previously evaluated:

(2) Create a possibility of a new or different kind of accident from any accident previously evaluated; or

(3) Involve a significant reduction in a margin of safety.

10 C.F.R. 50.92(c). If no such determination is made, then an amendment can be processed without initial public notice and made effective upon issuance, "even if adverse public comments have been received and even if an interested person meeting the provisions for intervention ... has filed a request for hearing." 10 C.F.R. 50.91(a)(4). Any required hearing need be held only after issuance of an amendment. Id. [5] By contrast, where such a determination is made, the opportunity for a full-scale hearing must be offered before the NRC can take any licensing action.

Some in industry have suggested that only minor modifications in the technical specifications and FSAR are needed to acknowledge MOX, that no unresolved safety questions are expected, and, therefore, that the NRC can approve MOX use under 10 C.F.R. 50.92. If the NRC proceeded in this fashion, as noted earlier, no prior notice of the application for amendment would be required and any hearing would come, if at all, after the amendment had already been approved.

Given the high visibility of the MOX program and likely controversy surrounding its use in individual reactors, the wisdom of industry’s suggested approach is questionable. [6] In any case, Dr. Lyman’s work underscores that, since the consequences of certain previously evaluated accidents may significantly increase when MOX fuel is used, the NRC is not likely to be able properly to make a "no significant hazards determination".

Indeed, Dr. Lyman’s study indicates that the increase in risk associated with the use of weapons-grade MOX in typical U.S. power reactors is so large that, according to NRC staff regulatory guidance, an application for a license amendment to use MOX "would not normally be considered." See Office of Nuclear Energy Research, Regulatory Guide 1.174, "An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis" 11 (July 1998). While this is not a strict prohibition, since the use of RG 1.174 is discretionary, it does strongly suggest that the staff would not regard such an application favorably without additional action on the part of the licensee, e.g., demonstrating quantitatively that the risk increase is not as large as estimated, undertaking compensatory measures to mitigate the increase in risk, or invoking unquantified benefits that justify the increase in risk.

(b) Generic versus Site Specific Considerations -- Even if a license amendment is subject to the full-scale, before-the-fact hearing process under 10 C.F.R. 50.92, another key question which still remains relates to the scope of the issues which will be decided in individual licensing as opposed to generic rulemaking proceedings. The Commission plainly has the power to resolve some generic issues generically. See Nuclear Information Resource Service v. NRC, 969 F.2d 1169 1175-1177 (D.C. Cir. 1992) (en banc); Kelley v. Selin, 42 F.3d 1501, 1511-1512 (6th Cir. 1995). [7] Once a rule is established, it "is not subject to attack by way of discovery, proof, argument or other means in any adjudicatory proceeding involving initial or renewal licensing ...." 10 C.F.R. 2.758(a). Noting that individual licensees would likely be unwilling to take on the burden of fuel design qualification, Westinghouse has suggested that the NRC could proceed by rulemaking under 10 C.F.R. Part 52 to license the "fuel design, fuel fabrication and fuel transportation methodology". [8] For its part, General Electric has posited that even a rulemaking is not necessary for fuel qualification and that the Commission can simply apply certain acceptance criteria for the new, MOX fuel to bring it within the "GE Standard Application for Reactor Fuel" ("GESTAR II"). [9]

Assuming that there is a generic qualification of MOX fuel, this would take certain issues off the table in individual plant licensings but should not result in a no significant hazards determination. As Dr. Lyman’s report makes clear, there are likely to be significant hazards associated with MOX fuel apart from its mechanical and thermal characteristics (which presumably would be analyzed during the Part 52 process). Moreover, it is impossible to neatly disentangle the generic use of MOX from site-specific safety issues, such as the impact of an increased source term on emergency evacuation zone distances, as well as various reactor-specific characteristics, such as the condition of the pressure vessel and the value of the core damage frequency.

Generic fuel qualification, it should be noted, might also result in significant constraints on reactor operation. For example, substantial limitations on the average burnup could plainly impact the operational cycle of many plants. Development of a new, MOX-specific source term to be used in Part 100 accident evaluations might likewise impact what can and cannot be done at particular reactor sites.

In addition to fuel qualification, some other issues may be best suited for rulemaking. For example, any policy questions about use of MOX could be dealt with in a generic fashion. Likewise, to allow the use of deadly force at a reactor site to protect plutonium, a change will be required to 10 C.F.R. Part 73 (Physical Protection of Plants and Materials).

Ultimately, what is at issue in individual licensing proceedings will depend upon which issues can properly be resolved by rulemaking or in other generic fashion. The industry would obviously like to simplify the licensing process as much as possible. Indeed, as industry representatives envision the process, it would not much differ from current practice where the vendor qualifies a new low enriched uranium fuel type, and the license amendment is essentially pro forma, involving a determination of no significant hazards under 10 C.F.R. 50.92 and rarely, if ever, a contested, adjudicatory hearing. Realistically, however, more is going to be required, and key issues will still have to be addressed in plant-by-plant licensings.

(c) Full Core Reloads -- Finally, it is important to emphasize that the transition from partial to full core MOX, if it takes place at all, should not be a simple incremental process, but instead would be a major change to the licensing basis triggering additional reviews under Section 50.92. Compared to partial core loads, full cores will require significant changes in reactor hardware and technical specifications, including installation of many additional control rod clusters and increases in the soluble boron concentration and/or enrichment.

End Notes

1. The FSAR describes and analyzes, among other matters, the reactor core. See 10 C.F.R. 50.34(b)(2)(i). In turn, it becomes the basis for the technical specifications ultimately included in the license. 10 C.F.R. 50.36(b).

2. An unreviewed safety question will be found where the probability or consequence of an event are increased; the possibility of a different type of event is created; or the margin of safety defined in the technical specification bases is reduced. 10 C.F.R. 50.59(a)(2).

3. A separate question is whether the NRC could make a "no significant hazards determination" for LTA licensing under 10 C.F.R. 50.92. The "no significant hazards determination" standards are discussed in more detail in the next section as regards the licensing of partial or full core MOX loads. Almost twenty years ago, the NRC did make such a determination in connection with experimental MOX use at the Ginna reactor. See 45 Fed. Reg. 29450 (1980).

4. While one industry representative has raised the possibility that a generic proceeding might be utilized "to authorize the use of MOX fuel at all light-water powered reactors without the issuance of individual amendment to each license," this would seem an unlikely scenario. Indeed, both uncertainties about its lawfulness and practical considerations, e.g., the public's site specific concerns about plutonium, militate against such an approach, and the NRC is unlikely to adopt it.

5. Any hearing, it should be noted, in connection with LTA loading or partial/full core loading, would entail full-scale, public adjudicatory procedures on all contested issues under Section 189(a) of the Act, 42 U.S.C. 2239(a), and under 10 C.F.R. Part 2, Subpart G. This includes the full array of discovery tools. 10 C.F.R. 2.740-2.744, and an opportunity to present oral testimony and cross-examine witnesses at the hearing. While the courts have never expressly held that Section 189(a) requires an "on-the-record" adjudicatory hearing in every case, they have stated that "there is much to suggest" that it does, and have noted that, in any event, it has been the Commission's consistent practice to hold on the record hearings in license adjudications. See Unioin of Concerned Scientists v. NRC, 735 F.2d 1437, 1444-1445, n. 12 (D.C. Cir. 1984), cert. denied, 469 U.S. 1132 (1985). Under the Commission's rules, such a hearing must be held when requested by a party whose interest would be affected by license approval. See 10 C.F.R. 2.105(e)(2).

6. Indeed, even Westinghouse admitted in a 1994 report on MOX that "the commission is not likely to conclude a no significant hazards consideration, since the amendment has not been previously evaluated."

7. Where the Commission proceeds by rulemaking rather than plant-by-plant adjudicatory licensing, only a "legislative type" process is required, and intervenors have no rights of discovery or cross-examination. See generally 10 C.F.R. Part 2, Subpart H; Kelley v. Selin, 42 F.3d 1501 (6th Cir. 1995).

8. The effect of generic qualification of MOX fuel, it should be noted, would likely be to qualify that fuel for all reactors of the same type, not just the four to eight reactors which are the likely candidates to burn MOX in the materials disposition program.

9. As described by General Electric, Amendment 22 to GESTAR II establishes a set of fuel licensing acceptance criteria for new fuel designs, and fuel designs which meet these criteria "constitutes NRC acceptance and approval for use in BWRs."