ML12249A069
| ML12249A069 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 09/04/2012 |
| From: | Molden J Northern States Power Co, Xcel Energy |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| Shared Package | |
| ML122490127 | List: |
| References | |
| L-PI-12-066, TAC ME6984, TAC ME6985 | |
| Download: ML12249A069 (24) | |
Text
ENCLOSURE 3 CONTAINS PROPRIETARY INFORMATION -
WITHHOLD FROM PUBLIC DISCLOSURE IN ACCORDANCE WITH 10 CFR 2.390 Xcel EnergyB SEP 0 4 2012 L-PI-12-066 10 CFR 50.90 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Prairie Island Nuclear Generating Plant, Units 1 and 2 Dockets 50-282 and 50-306 Renewed License Nos. DPR-42 and DPR-60 Response to Requests for Additional lnformation (RAI) Associated with Spent Fuel Pool Criticality Changes (TAC Nos. ME6984 and ME69851 In a letter to the U.S. Nuclear Regulatory Commission (NRC) dated August 19, 201 1 (Agencywide Documents and Management System (ADAMS) Accession No. MLI 12360231), the Northern States Power Company, a Minnesota corporation doing business as Xcel Energy (hereafter "NSPM"), requested an amendment to the Technical Specifications (TS) for Prairie Island Nuclear Generating Plant (PINGP). The proposed amendment requested TS changes and approval of the submitted criticality safety analysis methodology.
To complete their review, the NRC staff requested additional information by letter dated March 20,2012 (ADAMS Accession No. ML120620389) and NSPM responded by letter dated May 16, 201 2 (ADAMS Accession No. ML12139A198). By letter dated August 7,
2012 (ADAMS Accession No. ML12215A252), NRC issued a subsequent request for additional information (RAI) to clarify the previous responses. to this letter provides the non-proprietary NSPM response to the August 7, 2012 RAI. Enclosure 2 provides the Westinghouse Application for Withholding Proprietary lnformation from Public Disclosure CAW-12-3522, accompanying Affidavit, Proprietary Information Notice, and copyright notice. Enclosure 3 contains the proprietary version of the Westinghouse-prepared replies.
As Enclosure 3 contains information proprietary to Westinghouse Electric Company LLC, it is supported by the enclosed affidavit (Enclosure 2) signed by Westinghouse, the owner of the information. The affidavit sets forth the basis on which the information may be withheld from public disclosure by the Commission and addresses with specificity the considerations listed in paragraph (b)(4) of Section 2.390 of the Commission's regulations. Accordingly, it is respectfully requested that the information which is proprietary to Westinghouse be withheld from public disclosure in accordance with 10 CFR 2.390 of the Commission's regulations.
1717 Wakonade Drive East Welch, Minnesota 55089-9642 Telephone: 651.388.1 121
Document Control Desk Page 2 Correspondence with respect to the copyright or proprietary aspects of the items provided in Enclosure 3 of this letter or the supporting Westinghouse affidavit should reference CAW-12-3522 and should be addressed to J. A. Gresham, Manager, Regulatory Compliance, Westinghouse Electric Company LLC, Suite 428, 1000 Westinghouse Drive, Cranberry Township, Pennsylvania 16066.
NSPM submits this supplement in accordance with the provisions of 10 CFR 50.90.
The supplemental information provided in this letter does not impact the conclusions of the Determination of No Significant Hazards Consideration and Environmental Assessment presented in the August 19, 201 1 submittal.
In accordance with 10 CFR 50.91, NSPM is notifying the State of Minnesota of this License Amendment Request (LAR) supplement by transmitting a copy of this letter to the designated State Official.
If there are any questions or if additional information is needed, please contact Glenn Adams at (612) 330-6777.
Summarv of Commitments This letter contains no new commitments.
I declare under penalty of perjury that the foregoing is true and correct.
Executed on SEP 0 4 2012 VSite Vice President, Prairie Island Nuclear Generating Plant Northern States Power Company - Minnesota Enclosures (3) cc:
Regional Administrator, Region Ill, USNRC Project Manager, Prairie Island Nuclear Generating Plant, USNRC Resident Inspector, Prairie Island Nuclear Generating Plant, USNRC State of Minnesota (without enclosures)
Westinghouse-Prepared RAI Responses Non-Proprietary Note that the pages of this Enclosure have the following information in the header:, Revision 0, 08/24/2012 21 pages follow
Westinghouse Non-Proprietary Class 3 Revision 0 08/24/2012 During a Jtule 21, 2012, teleconference, the licetlsee provided clarificatioi~s on the KENO tllodel supporting the gadolitlia setlsitivity analysis in terms of assumed buxi~up distributiotl and axial poisoil loading.
A review of NUREGICR-6760 shows that the axial effects were not considered for the gadoliiiia burnable absorber. NUREGICR-6760 appears to suggest that a 2-D illode1 may under-predict tlie integral fuel burnable absorber effects relative to a 3-D model that it~cludes an axial bwnup distributiotl and actual poisoil loading, To ensure that the no-gadoliilia assuinption remains valid for the fi~ll range of credited burtlup, provide a quantitative analysis modelitlg the effects of axially-distributed bur~lup and appropriate axial poison loading.
NUREGICR-6760 also appears to indicate that the spectral hardeniilg due to the presence of strong neutron absorbers inay also affect the results. Therefore, include both borated and uilborated conditions ill the analysis.
Westinghouse Non-Proprietary Class 3 Table 1-1: [
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Westinghouse Non-Proprietary Class 3 Table 1-2: [
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- 1. "Prairie IslaiidNuclear Generating Plant, Units 1 and 2 - Request for Additional IiIformatioa Related to License Amendment Request for Spent Fuel Pool Criticality Clianges", ADAMS Accession Number: ML120620389, March 2012.
- 2. C. E. Sanders, et al., "Study of tlie Effect of Integral Burnable Absorbers for PWR B~uiiup Credit",
NUREGICR-6760, Oak Ridge National Laboratory, Oak Ridge, TN, Marc11 2002.
- 3. c'Response to Requests for Additional Infornlatioii (RAI) Associated with Spent Fuel Pool Criticality Changes" ADAMS AccessioiiNumber: ML121394A198, May 2012.
Westinghouse Non-Proprietary Class 3 Revision 0 08/24/2012 The response to RAT-SRXB-2 does not appear to adequately address Array G (3x3 with a rod cluster control assembly). Show that the selected design basis assembly remains limiting for Array G.
Resuonse:
Table 2-1 shows the results of a conlparison between the Optinlized Fuel Assenlbly (OFA) and the 422 Vantage + (422V+) fuel assembly designs in Array G. [
Table 2-1: L la"
Westinghouse Non-Proprietary Class 3 Revision 0 08/24/2012 The response to RAT-SRXB-3 shows the optimum condition for 4 percent 2 3 5 ~
fresh fuel.
- a. What is tlle basis for 4 percent 2 3 5 ~
assulllption?
- b. What accounts for the difference hl k-effective results between Table 3-1 (12x12 case) and Figure 3-2 at the volunle fraction used ill the fiilal analysis?
Resuonse:
a.) The assunption of 4.0 wt% 2 3 5 ~
was selected because this value correspollds to the actual highest allowable initial etlricl~il~ent of the actual fuel that was co~~solidated at Prairie Island. As described in Section 3.6.3.1 of WCAP-17400-P @g. 3-20), all cot~solidated fitel is depleted fuel wit11 an e~uiclul~eat less than or equal to 4.0 wvt% 2 3 5 ~. Tlus information was coilfirmed and reiterated in the response to RAI-SRXB-3 of Round 1.
b.) In reviewing the data provided in the response to RAI 3 fiom Round 1 for the 12x12 case ill Table 3-1 and the data in Figure 3-2, the illformatioil presented for the 12x12 case was inaccurately described and reported.
The data from Table 3-1 of the Round 1 response is corrected in Table 3-1 below. [
- Table 3-1: [
1 n'c a,c 1
Westinghouse Non-Proprietary Class 3 Revision 0 08/24/2012
Westinghouse Non-Proprietary Class 3 Revision 0 081241201 2 RAI-SRXB-4 (Axial blankets): Show that ileglecthlg tlie hollow aniiular pellets in tile blailkets is always coi~ervative.
The use of annular blankets at Prairie Island has been reviewed, and the reactivities of assel~lblies wit11 annular blankets and with solid blankets were calculated. The reactivity differences between these asseniblies for a range of burnups were calculated and are provided it1 Table 4-1 and Table 4-2.
- I m
p a
c t
of modeling Annular Axiz~lankets iii Array A
Westinghouse Non-Proprietary Class 3
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Revision 0 08/24/2012 Westinghouse Non-Proprietary Class 3 Revision 0 08/24/2012 RAI-SRXB-5 (Axial profile):
Provide the analysis results that support the selection of the axial burnup profiles used in the analysis (e.g., k-effective results and correspo~~ding "shape depletion factors").
Westinghouse Nan-Proprietary Class 3 Revision 0 081241201 2
Westinghouse Non-Proprietary Class 3 Revision 0 08/24/2012 RAI-SRXB-6 (Operation with control rods):
In Figures 6-1 through 6-10, what are the differences in assumptions between the "Design basis" cases and the "Rodded cases?
pesuonse:
The differences in assun~ptions between the "Design basis" cases and the "Rodded cases are due to differences in the input paranleters to the depletion code used to develop the isotopic inventory. [
Westinghouse Non-Proprietary Class 3 Revision 0 08/24/2012
Westinghouse Non-Proprietary Class 3
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Revision 0 08/24/20 12 I""
Westinghouse Non-Proprietary Class 3 Revision 0 08/24/2012
westinghouse Non-Proprietary Class 3 Revision 0 08/24/2012 Table 6-2: [ [
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Westinghouse Nan-Proprietary Class 3 Revision 0 08/24/2012 References
- 1. WCAP-17400-P, "Prairie Island Units 1 and 2 Spent Fuel Pool Criticality Safety Analysis", July 2011.
- 2. DSS-ISG-2010-1, "Staff Guidance Regarding the Nuclear Criticality Safety Analysis for Spent Fuel Pools." Accession Nuinber ML110620086, Nuclear Regulatory Conln~issioii, Rockville, MD, October 201 1.
Westinghouse Non-Proprietary Class 3 Revision 0 08/24/2012 RAI-SRXB-7 (Criticality code validation fission product bias):
The specifics of the referenced Turkey Point analysis differ fro111 the PINGP analysis. Show that the approach used in the PINGP analysis is conservative relative to the method described in the interinl staff guidance.
Response
The itlethod described in the Interinl Staff ~uidance (ISG), DSS-ISG-2010-1 (Reference 1) is:
"An acceptable tileans of including isotopes that are not explicitly represented in the critical experiments used in the validation would be to increase the bias and bias ~ulcertainty by an amount proportional to the reactivity worth of the isotopes not explicitly validated."
To deter~niae the impact of using the metl~od given in the ISG, Westinghouse increased the bias and bias uncertainty of the validation suite by [
Westinghouse Non-Proprietary Class 3 Revision 0 08/24/20 12 Westinghouse Non-Proprietary Claa 3 Revision 0 08/24/20 12
Westinghouse Non-Proprietary Class 3 Revision 0 08/24/2012 References
- 1. DSS-ISG-2010-1, "Staff Guidance Regarding the Nuclear Criticality Safety Analysis for Spent Fuel Pools." Accession Number ML110620086, Nuclear Regulatory Conu~iission, Rockville, MD, October 201 1.
- 2. WCAP-17400-P, "Prairie Island Units 1 and 2 Spent Fuel Pool Criticality Safety Analysis", July 2011.
- 3. C. V. Parks, et al., "Review and Prioritization of Technical Issues for Burnup Credit of LWR Fuel",
NUREGICR-6665, Oak Ridge National Laboratory, Oak Ridge, TN, February 2000.