ML041680523
| ML041680523 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 06/08/2004 |
| From: | Curran D, Edwin Lyman Blue Ridge Environmental Defense League, Harmon, Curran, Harmon, Curran, Spielberg & Eisenberg, LLP |
| To: | Atomic Safety and Licensing Board Panel |
| Byrdsong A T | |
| References | |
| 50-413-OLA, 50-414-OLA, ASLBP 03-815-03-OLA, RAS 7941 | |
| Download: ML041680523 (10) | |
Text
RELATED CORRESPONDENGE June 8, 2004 UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION DOCKETED USNRC WF.)F. T-IF. ATO)MIC GAPFF AND TJC.NTG FOARD June 15,2004 (10:08AM)
In the Matter of ) OFFICE OF SECRETARY
) RULEMAKINGS AND DUKE ENERGY CORPORATION ) Docket Nos. 50-413-OIA ADJUDICATIONS STAFF
) 50-414-OLA
)
(Catawba Nuclear Station )
Units 1 and 2) )
BLUE RIDGE ENVIRONMENTAL DEFENSE LEAGUE'S RESPONSE TO NRC STAFF'S SECOND SET OF INTERROGATORIES AND REQUEST FOR PRODUCTION OF DOCUMENTS In accordance with the schedule established in the Atomic Safety and Licensing Board's
("ASLB's") May 25, 2004, Order (Regarding Proposed Redacted Memorandum & Order, and Proposed Schedule Changes), Blue Ridge Enviromnental Defense League ("BREDL") hereby responds to NRC Staff's Second Set of Interrogatories and Requests for Production of Documents Directed to Blue Ridge Environmental Defense League (April 26, 2004).
BREDL notes that this response does not include answers to discovery requests that relate only to Contentions II or ml, which are no longer part of this proceeding.
INTIFRROGATORLES
- 1. In its response to NRC Staff's First Set of Interrogatories and Request for Production of Documents to the Blue Ridge Environmental Defense League, Interrogatory 30, BREDL stated that Duke had not performed a comprehensive analysis of the difference in radionuclide inventories for all important radio nuclides. In this context, please identify (a) how the Duke core inventory analysis was deficient, identifying, with specificity, all areas of deficiency, (b) which radio nuclides, omitted by Duke, should have been included, and (c) any core inventory analyses that BREDL performed, had performed at their request or intends to perform.
RFQP0N,.vE- BREDL does not plan to respond to this question, as it is primarily relevant to source term issues that were to have been considered in Contention II, which has been dropped.
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Nevertheless, BREDL notes that although the differences in radionuclide inventory between MOX and LEU fuel affect parameters relevant to Contention I, such as linear power density and decay heat, BREDL does not assert that Duke's calculations of these parameters is significantly in error. Therefore, BREDL does not assert that Duke's core inventory analysis is deficient with respect to computation of parameters relevant to Contention I.
- 2. Identify and describe in detail, providing all bases and justification for, BREDL's position, and any analyses or evaluations that BREDL, its experts, agents or employees, have performed and/or expect to perform or to rely upon in its testimony and/or in examination of Duke or Staff witnesses, to demonstrate that Duke's assessment of the difference in the magnitude of fission product release during gap release phase for an LEU fuel assembly and a MOX lead test assembly is inadequate.
RE.QPON.sF BREDL does not plan to respond to this question, as it is primarily relevant to source term issues that were to have been considered in Contention II, which has been dropped.
Although BREDL understands that the differences in fission gap release between MOX and LEU fuel affect parameters relevant to Contention I, such as gap conductance, BREDL does not assert that Duke's calculations of these parameters is significantly in error. Therefore, BREDL does not assert that Duke's calculation of fission product gap release is deficient with respect to computation of parameters relevant to Contention I.
- 3. Identify and describe in detail, providing all bases and justification for, BREDL's position, and any analyses or evaluations that BREDL, its experts, agents or employees, have performed and/or expect to perform or to rely upon in its testimony and/or in examination of Duke or Staff witnesses, that Duke's scaling approach to evaluating the consequences of using MOX LTAs is invalid.
RF£.qPONF- BREDL does not plan to respond to this question, as it is primarily relevant to source term issues that were to have been considered in Contention II, which has been dropped.
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- 4. Explain how, in BREDL's view, the phenomenon of fuel-clad interaction would affect fuel relocation during a LOCA in a way that is different for M5-clad MOX fuel than for M5-clad LEU fuel. Provide all bases and support for the explanation.
RFSPN1VSF- Jn BREDL's view, there is substantial expert opinion to support the claim that fuel-clad bonding has a substantial impact on fuel relocation behavior during a design-basis LOCA.
There is also evidence to suggest that there are significant differences in the characteristics of pellet-clad interaction between MOX and LEU fuels that may result in a more severe relocation effect for MOX than for LEU. During NRC's recent expert elicitation (PIRT) process on LOCA issues for high-burnup fuel, all four participating experts agreed that "chemical and mechanical bonding between the fuel pellet and the cladding ... " was of high importance to the fuel relocation phenomenon, because "bonding could significantly affect the relocation characteristics by impeding pellet fragment movement." NUREG/CR-6744, "Phenomenon Identification and Ranking Tables for Loss-of-Coolant Accidents in Pressurized and Boiling Water Reactors Containing High-Burnup Fuel," Appendix D, Table D-1 at D-69 (December 2001).
According to IPSN (now IRSN), tight fuel-clad bonding may delay the onset of fuel relocation. A. Mailliat and M. Schwartz, IPSN, "Need for Experimental Programmes on LOCA Issues Using High-Burnup and MOX Fuels." NUREG/CP-0 176, Proceedings of the NRC Nuclear Safety Research Conference at 433 (March 2002). Tight bonding has also been observed at the Halden reactor in Norway to retard the rate of balloon formation. Nuclear Energy Agency, NEA/CSNI/R(2003)9, Ongoing and PlannedFuel Safety Research in NEA Member States at 79 (March 5, 2003).
With regard to differences in fuel-clad bonding behavior between LEU and MOX fuels, BREDL again notes NRC's statement that "chemical bonding between the pellets and the 3
cladding, which may be different for MOX pellets and U02 pellets, may affect the ballooning process and hence the clad behavior." Agency Plan for Confirmatory Research AssociatedWith the Use of Mixed-Oxide Fuel in Commercial Light-Water Reactors, Attachment at 2 (February 11, 2000). This claim is supported by experimental evidence that MOX fuel is more resistant to clad failures due to pellet-clad mechanical interaction (PCMI) than LEU fuel, even at high burnups. Nuclear Energy Agency, NEAINSC/DOC(2004)8, InternationalSeminar on Pellet-CladInteractionswith Water Reactor Fuels at 20 (May 6, 2004). This phenomenon is not well-understood but may imply that the pellet-clad bond is weaker for MOX fuel, in which case MOX fuel may have a greater propensity to earlier and more extensive fuel relocation than LEU.
In Duke's April 14, 2004, Response to BREDL's first set of discovery requests, Duke stated that the Framatome design-basis LOCA analysis for the MOX LTAs did not assume any fuel-clad bonding and was therefore "conservative" with respect to the requirement that the degree of cladding swelling not be underestimated. Id. at 14. However, in the absence of an assessment of whether and to what extent the pellet-clad interaction is weaker in MOX fuel than in LEU fuel, there is no way of knowing the degree to which this assumption is conservative for MOX fuel. Therefore, Duke's failure to properly account for this phenomenon contributes another uncertainty to the safety margin associated with Duke's design basis LOCA calculation.
Moreover, there is evidence to contradict Duke's assertion that "deterministic LOCA evaluations typically based on data taken from unirradiated cladding" are conservative with respect to clad swelling. According to IPSN (now IRSN), results from the PBF-LOC experiments found that irradiated rods experienced greater clad deformation during unirradiated rods during design-basis LOCA conditions. Mailliat and Schwartz at 432 (2002), op cit. There is simply no way to 4
determine whether Duke's design basis LOCA analysis underestimates 6r overestimates the degree of clad swelling (and hence the degree of fuel relocation) for MOX LTAs without additional experimental data from integral LOCA tests of high-burnup MOX fuel rods. Given the lack of data, BREDL finds unpersuasive the NRC's 1999 speculation, quoted by Duke in its April 14, 2004 set of responses to BREDL's discovery requests, that "a major effect is not expected" with regard to differences in pellet-clad bonding between MOX and LEU. Id. at 15.
- 5. Explain how, in BREDL's view, the phenomenon of particle size distribution of fuel fragments would affect fuel relocation during a LOCA in a way that is different for M5-clad MOX fuel than for M5-clad LEU fuel. Provide all bases and support for the explanation.
RFPON.'?F- In BREDL's view, the phenomenon of particle size distribution of fuel fragments would affect fuel relocation during a LOCA differently for MOX and LEU fuel if MOX fragmentation behavior during irradiation and subsequent LOCA results in generation of greater amounts of fine-grain material or smaller mean particle sizes. The former would increase the amount of fuel involved in the relocation and the latter would increase the filling ratio of the fragment bed following relocation. Either of these characteristics could result in a greater relocation-related increase in PCT for MOX than for LEU.
BREDL notes that the fuel relocation phenomenon has been observed in LEU fuel for rod bumups exceeding around 48 GWD/t. Mailliat and Schwartz at 432 (2002), op cit. This suggests that vulnerability to fuel relocation is associated with the development of the high-burnup "rim" region known to emerge in LEU fuel for burnups exceeding about 40-45 GWD/t.
For MOX fuel, a high-burnup rim-like region emerges in the outer layers of the plutonium agglomerates for much lower rod-average burnups than 40-45 GWD/t, because the 5
local burnups within the plutonium agglomerates increase much more rapidly than the rod-average burnups. Thus it is reasonable to expect that the onset of fuel relocation in MOX fuel may occur at lower rod-average burnups than in LEU fuel, if it is indeed related to the microstructure changes associated with rim formation. This would imply that MOX fuel will be vulnerable earlier in its irradiation history (and consequently for a longer time) than LEU fuel.
The greater thermo-mechanical stress in MOX fuel diring the blowdown phase of a LOCA compared to LEU may also increase its propensity for relocation. See BREDL Response to Duke's Second Set of Interrogatories, Response to Interrogatory 32(g) at 6-7 (June 8, 2004)
(hereinafter "BREDL's Response to Duke's Second Set of Interrogatories").
According to two out of four NRC experts who participated in the 2001 PIRT panel regarding high-burnup fuel, the composition of fuel (i.e. a specified MOX composition) is of high importance for consideration of fuel relocation effects because it "may affect the amount of fine grain material after relocation. Fuel structure and mechanical properties are influenced by fuel type." See NUREG/CR-6744, "Phenomenon Identification and Ranking Tables for Loss-of-Coolant Accidents in Pressurized and Boiling Water Reactors Containing High-Bumup Fuel,"
Appendix D, Table D-1 at D-67 (December 2001). One expert concluded that fuel composition was of moderate importance to relocation, stating that "the consequence of fuel fragments relocation (higher local decay heat and higher cladding temperature) could be more effective with MOX fuel than with U02 fuel" but that "the viscoelastic properties of the MOX should impair the fuel fragments relocation at high burnup." Id. at D-67. A fourth expert concluded that fuel composition would be of only low importance to relocation. Id. at D-67. This difference of expert opinion highlights the inadequacies of the experimental database with regard to integral 6
tests of MOX fuel under design-basis LOCA conditions, and underscores the significant uncertainties in Duke's design-basis LOCA analysis.
If MOX fuel produces a greater amount of fine-grain material than LEU,-greater filling ratios will occur after relocation, with greater corresponding increases in PCT. See BREDL Responses to Duke's Second Set of Interrogatories, Response to Interrogatory 42 at 16 (June 8, 2004). This effect will be compounded by the greater local power density of MOX fuel at moderate burnup (40 GWD/t) compared to LEU. BREDL is unable to provide any quantification of the greater vulnerability and more severe consequences of MOX fuel relocation compared to LEU fuel relocation because-of the absence of experimental data.
- 6. Explain how, in BREDL's view, the phenomenon of clad ballooning geometry would affect fuel relocation during a LOCA in a way that is different for M5-clad MOX fuel than for M5-clad LEU fuel. Provide all bases and support for the explanation.
RFEQP61&... In BREDL's view, to the extent that pellet-clad interaction is different between MOX and LEU fuel, the phenomenon of clad ballooning geometry would differ during a LOCA for M5-clad fuel and for M5-clad LEU fuel. For instance, if MOX indeed has a weaker pellet-clad bond at high burnups than LEU fuel, clad balloon size may be greater for MOX, increasing the propensity for relocation. See Response to Interrogatory 4.
RFQTTFST FOR PRODIT TMON OF DOCITMFNTS
- 1. Any and all documents referred to or relied upon in answering the above interrogatories.
RFSPONSF: All documents relied on in answering any of the above interrogatories are identified in the relevant interrogatory response.
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- 4. All answers to interrogatories, responses to requests for production or inspection, and documents provided in response to discovery requests served on BREDL by Duke.
RES'LQNS:F. The Staff has been served with all discovery responses by Duke. Any documents provided by Duke to BREDL should be requested directly from Duke.
Declaration of Dr. Edwin S. Lyman I certify that the facts in the foregoing discovery responses are true and correct to the best of my knowledge, and that the opinions expressed therein are based on my best professional judgment.
Dr. Edwin S. Lyman Respectfully submitte, Diane Curran Harmon, Curran, Spielberg, & Eisenberg, L.L.P.
1726 M Street N.W., Suite 600 Washington, D.C. 20036 202/328-3500 e-mail: dc1urran~harmanc1rran-conm June 8, 2004 8
CERTIFICATE OF SERVICE I hereby certify that on June 8, 2004, copies of Blue Ridge Environmental Defense League's Response to Duke Energy Corporation's Second Set of Interrogatories and Requests for Production of Documents and Blue Ridge Environmental Defense League's Response to NRC Staffs Second Set of Interrogatories and Request for Production of Documents were served on the following by e-mail and/or first-class mail, as indicated below.
Ann Marshall Young, Chair Susan L. Uttal, Esq.
Administrative Judge Antonio Fernandez, Esq.
Atomic Safety and Licensing Board Margaret J. Bupp, Esq.
U.S; Nuclear Regulatory Commission Office of the General Counsel Mail Stop: T-3F23 Mail Stop 15 D21 Washington, D.C. 20555 U.S. Nuclear Regulatory Commission E-mail: AMYsnrc. gov Washington, D.C. 20555-0001 I E-mail: slu~nrc.gov axf2@nrc.qgo, Anthony J. Baratta mjb5@nrc.gav Administrative Judge Atomic Safety and Licensing Board Mary Olson' U.S. Nuclear Regulatory Commission Southeast Office, Nuclear Information and Mail Stop: T-3F23 Resource Service Washington, D.C. 20555 P.O Box 7586 E-mail: AJB5@nrc. gov Asheville, NC 28802 E-mail: nirs. segmindspring. corm Office of Commission Appellate Adjudication U.S. Nuclear Regulatory Commission Lisa F. Vaughn, Esq.
Mail Stop: 0-16C1 Legal Dept. (PBO5E)
Washington, D.C. 20555 Duke Energy Corporation 526 South Church Street (ECI lX)
Thomas S. Elleman Charlotte, NC 28201-1006 Administrative Judge E-mail: 1 fvaughnsduke -energy.cor Atomic Safety and Licensing Board 4760 East Country Villa Drive Janet Marsh Zeller, Executive Director Tucson, AZ 85718 Blue Ridge Environmental Defense League E-mail: ellemanseos.ncsu.edu P.O. Box 88 Glendale Springs, NC 28629 David A. Repka, Esq. E-mail: BREDL6skybest. com Anne W. Cottingham, Esq.
Winston & Strawn, LLP 1400 L Street, N.W.
Washington, D.C. 20005-3502 E-mail: drepka~winston.'com acottinqgwinston.com
2 Office of the Secretary (original and two copies)
ATTN: Docketing and Service U.S. Nuclear Regulatory Commission Mail Stop: 0-16CI Washington, D.C. 20555 E-mail: HEARINGDOCKET~nrc . gov
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