ML15065A029

Seabrook Station - Response to Request for Additional Information for License Amendment Request 11-04, Changes to Technical Specifications for New Fuel Vault

ML15065A029
Person / Time
Site:	Seabrook
Issue date:	02/25/2015
From:	Dean Curtland NextEra Energy Seabrook
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
SBK-L-15036, TAC ME7946, TAC ME8688
Download: ML15065A029 (7)

Text

NExTeraENERGY GFebruary 25, 201510 CFR 50.90SBK-L-15036Docket No. 50-443U. S. Nuclear Regulatory CommissionAttn: Document Control DeskWashington, DC 20555-0001Seabrook StationResponse to Request for Additional Information for License Amendment Request 11-04,Changes to Technical Specifications for New Fuel VaultReferences:1. Seabrook Station License Amendment Request 11-04, "Changes to the TechnicalSpecifications for New and Spent Fuel Storage," SBK-L- 11245, January 30, 2012(ML12038A036).2. NRC letter to Seabrook Station, "Seabrook Station, Unit No. I. -SupplementalInformation Needed for Acceptance of Requested Licensing Action Regarding LicenseAmendment Request 11-04, Change to Technical Specifications for New and Spent FuelStorage (TAC No. ME7946)," March 30, 2012 (ML120730270).3. Seabrook letter to NRC, "Supplement to LAR 11-04, Changes to the TechnicalSpecifications for New and Spent Fuel Storage," SBK-L- 12099, May 10, 2012(ML12136A126).4. NRC letter to Seabrook Station, "Seabrook Station, Unit No. 1 -Acceptance LetterRegarding License Amendment Request 11-04, Changes to Technical Specifications forNew and Spent Fuel Storage (TAC No. ME8688)," June 19, 2012.5. NRC letter to Seabrook Station, "Seabrook Station, Unit No. 1 -Request for AdditionalInformation Regarding License Amendment Request 11-04, Changes to TechnicalSpecifications for New and Spent Fuel Storage (TAC No. ME8688)," July 24, 2012(ML12192A232).6. Seabrook letter to NRC, "Response to Request for Additional Information RegardingLicense Amendment Request 11-04, Changes to Technical Specifications for New andSpent Fuel Storage," SBK-L- 12199, September 20, 2012 (ML 12271 A276).NeBfaNextEra Energy Seabrook, LLG, P.O. Box 300, Lafayette Road, Seabrook, NHl 03874 U.S. Nuclear Regulatory CommissionSBK-L-15036/Page 27. NRC letter to Seabrook Station, "Seabrook Station, Unit No. 1 -Request for AdditionalInformation Regarding License Amendment Request 11-04, Changes to TechnicalSpecifications for New and Spent Fuel Storage (TAC No. ME8688)," December 5, 2012(ML12270A423).8. Seabrook letter to NRC, "Response to December 2012 Request for Additional InformationRegarding License Amendment Request 11-04, Changes to Technical Specifications forNew and Spent Fuel Storage," SBK-L- 13061, March 27, 2013 (ML 13099A022).9. Seabrook letter to NRC, "Request for Review and Approval of License AmendmentRequest (LAR) 11-04, Changes to Technical Specifications for New and Spent FuelStorage, in Two Parts," SBK-L- 13224, December 20, 2013(ML 13360A645).10. NRC letter to Seabrook Station, "Seabrook Station, Unit No. I -Request for AdditionalInformation for License Amendment Request 11-04, Changes to Technical Specificationsfor Spent Fuel Storage (TAC No. ME8688)," January 8, 2014.11. NRC letter to Seabrook Station, "Seabrook Station, Unit No. I -Request for AdditionalInformation for License Amendment Request 11-04, Changes to Technical Specificationsfor New Fuel Vault (TAC No. MF3283)," January 8, 2014 (ML13268A468).12. Seabrook letter to NRC, "Response to Request for Additional Information for LicenseAmendment Request 11-04, Changes to Technical Specifications for Spent Fuel Storage,"SBK-L-14018, January 29, 2014 (ML14035A218).13. Seabrook letter to NRC, "Response to Request for Additional Information for LicenseAmendment Request 11-04, Changes to Technical Specifications for New Fuel Vault,"SBK-L-14053, March 13, 2014 (ML14078A057).14. NRC letter to Seabrook Station, "Seabrook Station, Unit No. 1 -Issuance of AmendmentRegarding License Amendment Request Regarding Fuel Storage Changes (TAC No.ME8688)," September 3, 2014 (ML 14184A795).15. NRC letter to Seabrook Station, "Seabrook Station, Unit No. 1 -Request for AdditionalInformation for License Amendment Request 11-04, Changes to Technical Specificationsfor New Fuel Vault (TAC No. MF3283)," October 20, 2014 (ML14276A207).In Reference 1, NextEra Energy Seabrook, LLC (NextEra) submitted License AmendmentRequest (LAR) 11-04 to the Technical Specifications (TS) for Seabrook Station. The proposedchange would revise the TS for new and spent fuel storage as the result of new criticalityanalyses for the new fuel vault and the spent fuel pool.In Reference 2, the NRC requested supplemental information to support acceptance of the LAR11-04. NextEra supplied the information requested in Reference 3. In Reference 4, the NRCaccepted LAR 11-04 for review.In Reference 5, the NRC transmitted their first Request for Additional information on LAR 11-04. NextEra supplied the information requested in Reference 6.

U.S. Nuclear Regulatory CommissionSBK-L-15036/Page 3In Reference 7, the NRC transmitted their second Request for Additional information on LAR11-04. NextEra supplied the information requested in Reference 8.In Reference 9, NextEra requested that the spent fuel storage and new fuel vault segments ofLAR 11-04 be treated separately, so that approval of the spent fuel storage segment would not bedelayed by the remaining unresolved issues in the new fuel vault segment.In Reference 10, the NRC transmitted their third Request for Additional information on LAR 11-04 with questions on the spent fuel storage segment. Separately in Reference 11, the NRCtransmitted their fourth Request for Additional information on LAR 11-04 with questions on thenew fuel vault segment. NextEra supplied the information requested for the spent fuel pool inReference 12, and for the new fuel vault in Reference 13.In Reference 14, the NRC issued License Amendment 142 for spent fuel storage.In Reference 15, the NRC transmitted their fifth Request for Additional information on LAR 11-04 with questions on the new fuel vault segment. The responses to that RAI are provided belowin the enclosure to this letter. This response does not modify the changes to the TS as previouslyproposed and does not alter the conclusion in Reference 1 that the changes do not present asignificant hazards consideration.This letter contains no regulatory commitments.Should you have any questions regarding this letter, please contact Mr. Michael Ossing,Licensing Manager, at (603) 773-7512.I declare under penalty of perjury that the foregoing is true and correct.Executed on February Z5' , 2015.Sincerely,NextEra Energy Seabrook, LLCDean CurtlandSite Vice PresidentEnclosure U.S. Nuclear Regulatory CommissionSBK-L-15036/Page 4cc: D. Dorman, NRC Region I AdministratorJ. Lamb, NRC Project Manager, Project Directorate 1-2P. Cataldo, NRC Senior Resident InspectorMr. Perry PlummerDirector Homeland Security and Emergency ManagementNew Hampshire Department of SafetyDivision of Homeland Security and Emergency ManagementBureau of Emergency Management33 Hazen DriveConcord, NH 03305John Giarrusso, Jr., Nuclear Preparedness ManagerThe Commonwealth of Massachusetts-Emergency Management Agency400 Worcester RoadFramingham, MA 01702-5399 ENCLOSUREResponse to Request for Additional Information (RAI) for License Amendment Request 11-04,Changes to Technical Specifications for New Fuel Vault Response to Request for Additional Information (RAI) for License Amendment Request 11-04,Changes to Technical Specifications for New Fuel VaultNRC Question 1. Was there a basis for the 0.4 weight percent hydrogen used as the lowerlimit in the NFV concrete?Response:The Seabrook New Fuel Vault (NFV) concrete was constructed with a 3000 psi concretemixture, consisting of ASTM C 150, Type II Portland cement with a maximum water to cementratio of 0.50. The course aggregate of the Seabrook NFV concrete is composed of particles ofmeta-igneous and meta-quartzite rock, while the fine aggregate is primarily made up with quartzwith lesser amounts of feldspar, micaceous minerals, chelt, granite, and sand-sized particles ofthe coarse aggregate. In addition, no fly ash is found in the Seabrook NFV concrete. Thatconcrete composition has a Hydrogen content of 1.0 weight percent. This information on theSeabrook NFV concrete was noted in a previous RAI response (Reference 1.1).The concrete composition used in the Seabrook NFV criticality analysis is based on Hanford Dryconcrete, with 0.4 weight percent Hydrogen. Sensitivity analyses performed and documented inthe aforementioned previous RAI response noted that the NFV's reactivity for the optimummoderation case increased when decreasing the Hydrogen content, with negligible impacts forother isotopes or for all isotopes for the fully flooded case. Therefore, the Hanford Drycomposition was used in the model as it had a considerably lower Hydrogen content, thusbounding the reactivity calculated with the actual concrete composition.Reference1.1 Seabrook letter to NRC, "Response to December 2012 Request for Additional InformationRegarding License Amendment Request 11-04, Changes to Technical Specifications forNew and Spent Fuel Storage," SBK-L-13061, March 27, 2013.NRC Question 2. Can the hydrogen content drop over time in the NFV concrete?Response:Hydrogen is present in concrete in the form of water and hydrogenous reaction products from thechemical reaction between water and cement. The hydrogen content of concrete decreases fromthe time of placement due to evaporative losses. However, concrete with a hydrogen content of1.0% could not experience losses that would reduce the hydrogen content to below 0.4%.Water is present in hydrated cement paste as follows (Reference 2.1):* Chemically Combined Water -This water is an integral part of the microstructure of cementhydration products and is not lost on drying. For typical portland cement, the chemicalreaction resulting in hydration of the cement requires about 1 part (by weight) water forevery 4 parts cement (Reference 2.2).

" Interlayer Water -This water is strongly hydrogen bound between layers of hydrationproducts. This water is lost only on strong drying to 11 percent relative humidity." Adsorbed Water -This water is close to the solid surface of hydration products and is held tothe surface by hydrogen bonding. A major portion of the adsorbed water may be lost whenhydrated cement paste is dried to 30 percent relative humidity." Capillar Water -This water occupies voids that are larger than about 50 angstroms(50x 10- ° m or 5 nm), and is essentially free from the attractive forces associated withhydration products. Evaporation of capillary water starts to occur when ambient relativehumidity is less than 100 percent.As discussed in the response to question 1, the concrete mix from the NFV has a maximumwater-to-cement ratio of 0.5 (i.e., 2 parts water for every 4 parts cement). Because hydration ofcement requires about 1 part water for every 4 parts cement, half of the original water content ofthe NFV concrete is chemically combined in the hydration products and cannot be lost by drying.Given an original hydrogen content of 1.0%, the hydrogen content associated with chemicallybound water is 0.5%. This hydrogen content exceeds the 0.4% hydrogen used in the criticalityanalyses.The actual hydrogen content in the concrete will include more than only the chemically boundhydrogen because the interlayer water, adsorbed water, and a portion of the original capillarywater will remain in the concrete. The atmospheric conditions at Seabrook Station aresufficiently humid to limit evaporative losses. The National Oceanic and AtmosphericAdministration (NOAA) tracks weather data at its monitoring station in Concord, NewHampshire (Reference 2.3). Data for average relative humidity from 1965 to 2012 show anaverage daily high of 80% and an average daily low of 53%. The least humid month (April) hasan average daily low humidity of 44%, which would be the minimum humidity present in theconcrete pores. Atmospheric humidity is not low enough to cause evaporation of interlayerwater and adsorbed water.References2.1 Mehta, P. and Monteiro, P., "Concrete: Microstructure, Properties, and Materials," FourthEdition. McGraw-Hill Education, 2014.2.2 Powers, T., "A Discussion of Cement Hydration in Relation to the Curing of Concrete,"Proceedings of the Highway Research Board, Volume 27, 1947.2.3 "Comparative Climatic Data For the United States Through 2012," National Oceanic andAtmospheric Administration. Retrieved on February 19, 2015 from websitehttp://wwwl .ncdc.noaa.gov/pub/data/ccd-data/CCD-2012.pdf