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MONTHYEARSBK-L-11245, License Amendment Request 11-04, Changes to the Technical Specifications for New and Spent Fuel Storage2012-01-30030 January 2012 License Amendment Request 11-04, Changes to the Technical Specifications for New and Spent Fuel Storage Project stage: Request SBK-L-12099, Supplement to LAR 11-04, Changes to the Technical Specifications for New and Spent Fuel Storage2012-05-10010 May 2012 Supplement to LAR 11-04, Changes to the Technical Specifications for New and Spent Fuel Storage Project stage: Supplement ML12192A2322012-07-24024 July 2012 Request for Additional Information Regarding License Amendment Request 11-04, Changes to Technical Specifications for New and Spent Fuel Storage Project stage: RAI SBK-L-12199, Response to Request for Additional Information Regarding License Amendment Request 11-04, Changes to Technical Specifications for New and Spent Fuel Storage2012-09-20020 September 2012 Response to Request for Additional Information Regarding License Amendment Request 11-04, Changes to Technical Specifications for New and Spent Fuel Storage Project stage: Response to RAI ML12270A4312012-10-0202 October 2012 Request for Withholding Infomation from Public Disclosure Regarding License Amendment Request 11-04, Changes to Technical Specifications for New and Spent Fuel Storage Project stage: Other ML12270A4232012-12-0505 December 2012 Non-Proprietary - Request for Additional Information Regarding License Amendment Request 11-04. Changes to Technical Specifications for New and Spent Fuel Storage Project stage: RAI SBK-L-13061, Response to December 2012 Request for Additional Information Regarding License Amendment Request 11-04, Changes to Technical Specifications for New and Spent Fuel Storage2013-03-27027 March 2013 Response to December 2012 Request for Additional Information Regarding License Amendment Request 11-04, Changes to Technical Specifications for New and Spent Fuel Storage Project stage: Request ML13095A1222013-04-26026 April 2013 Request for Withholding Information from Public Disclosure Regarding License Amendment Request 11-04, Changes to Technical Specifications for New and Spent Fuel Storage Project stage: Withholding Request Acceptance ML13095A0262013-04-26026 April 2013 Request for Withholding Information from Public Disclosure Regarding License Amendment Request 11-04, Changes to Technical Specifications for New and Spent Fuel Storage Project stage: Withholding Request Acceptance ML13095A1012013-05-0202 May 2013 Request for Withholding Information from Public Disclosure Regarding License Amendment Request 11-04, Changes to Technical Specifications for New and Spent Fuel Storage Project stage: Withholding Request Acceptance ML13094A4092013-05-0202 May 2013 Request for Withholding Information from Public Disclosure Regarding License Amendment Request 11-04, Changes to Technical Specifications for New and Spent Fuel Storage Project stage: Withholding Request Acceptance SBK-L-13224, Request for Review and Approval of License Amendment Request (LAR) 11-04, Changes to Technical Specifications for New and Spent Fuel Storage, in Two Parts2013-12-20020 December 2013 Request for Review and Approval of License Amendment Request (LAR) 11-04, Changes to Technical Specifications for New and Spent Fuel Storage, in Two Parts Project stage: Request ML13268A4682014-01-0808 January 2014 Request for Additional Information for License Amendment Request 11-04, Changes to Technical Specifications for New and Spent Fuel Storage Project stage: RAI SBK-L-14018, Response to Request for Additional Information for License Amendment Request 11-04, Changes to Technical Specifications for Spent Fuel Storage2014-01-29029 January 2014 Response to Request for Additional Information for License Amendment Request 11-04, Changes to Technical Specifications for Spent Fuel Storage Project stage: Response to RAI ML14184A7952014-09-0303 September 2014 Issuance of Amendment Regarding License Amendment Request Regarding Fuel Storage Changes Project stage: Approval SBK-L-15036, Response to Request for Additional Information for License Amendment Request 11-04, Changes to Technical Specifications for New Fuel Vault2015-02-25025 February 2015 Response to Request for Additional Information for License Amendment Request 11-04, Changes to Technical Specifications for New Fuel Vault Project stage: Response to RAI 2013-12-20
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Category:Letter type:SBK
MONTHYEARSBK-L-23053, Radiological Emergency Plan (Ssrep), Revision 802023-06-22022 June 2023 Radiological Emergency Plan (Ssrep), Revision 80 SBK-L-23031, 2022 Annual Radioactive Effluent Release Report2023-04-28028 April 2023 2022 Annual Radioactive Effluent Release Report SBK-L-23044, 2022 Annual Radiological Environmental Operating Report2023-04-28028 April 2023 2022 Annual Radiological Environmental Operating Report SBK-L-23033, 2022 Annual Environmental Operating Report2023-04-11011 April 2023 2022 Annual Environmental Operating Report SBK-L-22093, 75 Day and 150 Day Submittal Letters2022-12-0101 December 2022 75 Day and 150 Day Submittal Letters SBK-L-22113, Radiological Emergency Plan (Ssrep), Revision 792022-11-16016 November 2022 Radiological Emergency Plan (Ssrep), Revision 79 SBK-L-22114, Independent Spent Fuel Storage Installation (Isfsi), Cask Registration2022-11-0909 November 2022 Independent Spent Fuel Storage Installation (Isfsi), Cask Registration SBK-L-22112, Independent Spent Fuel Storage Installation (ISFSI) Cask Registration2022-11-0303 November 2022 Independent Spent Fuel Storage Installation (ISFSI) Cask Registration SBK-L-22094, Relief Request 4RA-22-001, Proposed Alternative in Accordance with 10 CFR 50.55a(z)(2)2022-10-26026 October 2022 Relief Request 4RA-22-001, Proposed Alternative in Accordance with 10 CFR 50.55a(z)(2) SBK-L-22105, Supplement to 2021 Annual Radioactive Effluent Release Report2022-10-24024 October 2022 Supplement to 2021 Annual Radioactive Effluent Release Report SBK-L-22103, 5 to the Physical Security Plan, Training and Qualification Plan and Safeguards Contingency Plan2022-10-12012 October 2022 5 to the Physical Security Plan, Training and Qualification Plan and Safeguards Contingency Plan SBK-L-22102, Independent Spent Fuel Storage Installation (ISFSI) Cask Registration2022-10-0606 October 2022 Independent Spent Fuel Storage Installation (ISFSI) Cask Registration SBK-L-22080, Submittal of 10 CFR 72.48 Report of Changes, Tests and Experiments for August 2020 to July 20222022-08-12012 August 2022 Submittal of 10 CFR 72.48 Report of Changes, Tests and Experiments for August 2020 to July 2022 SBK-L-22054, SBK-L-22054 - License Amendment Request 22-01, Application to Revise Technical Specifications to Adopt TSTF-577, Revised Frequencies for Steam Generator Tube Inspections2022-06-0909 June 2022 SBK-L-22054 - License Amendment Request 22-01, Application to Revise Technical Specifications to Adopt TSTF-577, Revised Frequencies for Steam Generator Tube Inspections SBK-L-22044, 2021 Annual Radioactive Effluent Release Report2022-04-29029 April 2022 2021 Annual Radioactive Effluent Release Report SBK-L-22036, Steam Generator Tube Inspection Report2022-04-25025 April 2022 Steam Generator Tube Inspection Report SBK-L-22040, Radiological Emergency Plan (Ssrep), Revision 7822022-04-20020 April 2022 Radiological Emergency Plan (Ssrep), Revision 782 SBK-L-22024, Response to Request for Additional Information (Raj) Regarding License Amendment Request 21-01, Revise 120-Volt AC Vital Instrument Panel Requirements2022-03-0707 March 2022 Response to Request for Additional Information (Raj) Regarding License Amendment Request 21-01, Revise 120-Volt AC Vital Instrument Panel Requirements SBK-L-22003, Inservice Inspection Examination Report2022-01-24024 January 2022 Inservice Inspection Examination Report SBK-L-21126, Fourth 10 Year Interval - Inservice Inspection (ISI) Program Plan2022-01-0404 January 2022 Fourth 10 Year Interval - Inservice Inspection (ISI) Program Plan SBK-L-21135, Submittal of Changes to the Seabrook Station Technical Specification Bases2021-12-29029 December 2021 Submittal of Changes to the Seabrook Station Technical Specification Bases SBK-L-21108, Core Operating Limits Report for Cycle 222021-11-0404 November 2021 Core Operating Limits Report for Cycle 22 SBK-L-21106, Transmittal of WCAP-18607-NP, Analysis of Capsule X from the NextEra Energy Seabrook Unit 1 Reactor Vessel Radiation Surveillance Program2021-09-30030 September 2021 Transmittal of WCAP-18607-NP, Analysis of Capsule X from the NextEra Energy Seabrook Unit 1 Reactor Vessel Radiation Surveillance Program SBK-L-21105, Withdrawal of Emergency License Amendment Request 21-02, Service Water System I Ultimate Heat Sink One-Time Allowed Outage Time (AOT) Extension2021-09-27027 September 2021 Withdrawal of Emergency License Amendment Request 21-02, Service Water System I Ultimate Heat Sink One-Time Allowed Outage Time (AOT) Extension SBK-L-21103, Request for Exercise of Enforcement Discretion2021-09-25025 September 2021 Request for Exercise of Enforcement Discretion SBK-L-21104, Emergency License Amendment Request 21-02, Service Water System I Ultimate Heat Sink Onetime Allowed Outage Time (AOT) Extension2021-09-25025 September 2021 Emergency License Amendment Request 21-02, Service Water System I Ultimate Heat Sink Onetime Allowed Outage Time (AOT) Extension SBK-L-21098, Supplement to License Amendment Request 21-01, Revise 120-Volt AC Vital Instrument Panel Requirements2021-09-22022 September 2021 Supplement to License Amendment Request 21-01, Revise 120-Volt AC Vital Instrument Panel Requirements SBK-L-21083, NextEra Energy Seabrook, LLC - Relief Request 3IR-18 and 3IR-19 for End of Third 10-Year ISI Interval for Examinations with Limited Coverage2021-08-18018 August 2021 NextEra Energy Seabrook, LLC - Relief Request 3IR-18 and 3IR-19 for End of Third 10-Year ISI Interval for Examinations with Limited Coverage SBK-L-21067, License Amendment Request 21-01, Revise 120-Volt AC Vital Instrument Panel Requirements2021-07-21021 July 2021 License Amendment Request 21-01, Revise 120-Volt AC Vital Instrument Panel Requirements SBK-L-21049, Revision to Updated Final Response to NRC Generic Letter 2004-022021-06-24024 June 2021 Revision to Updated Final Response to NRC Generic Letter 2004-02 SBK-L-21056, Response to Request for Additional Information Regarding Seabrook Steam Generator Tube Inspection Report Review References:2021-05-20020 May 2021 Response to Request for Additional Information Regarding Seabrook Steam Generator Tube Inspection Report Review References: SBK-L-21045, Submittal of 2020 Annual Radioactive Effluent Release Report2021-04-30030 April 2021 Submittal of 2020 Annual Radioactive Effluent Release Report SBK-L-21044, 2020 Annual Radiological Environmental Operating Report2021-04-30030 April 2021 2020 Annual Radiological Environmental Operating Report SBK-L-21042, Response to RIS 2021-01 Preparation and Scheduling of Operator Licensing Examinations2021-04-22022 April 2021 Response to RIS 2021-01 Preparation and Scheduling of Operator Licensing Examinations SBK-L-21033, Response to Request for Additional Information (RAI) Regarding License Amendment Request (LAR) 20-02, Resolve Non-Conservative Heat Flux Hot Channel Factor (Fo(Z)) Requirements2021-03-24024 March 2021 Response to Request for Additional Information (RAI) Regarding License Amendment Request (LAR) 20-02, Resolve Non-Conservative Heat Flux Hot Channel Factor (Fo(Z)) Requirements SBK-L-21023, Radiological Emergency Plan (Ssrep), Revision 772021-03-0404 March 2021 Radiological Emergency Plan (Ssrep), Revision 77 SBK-L-20154, Submittal of Changes to the Seabrook Station Technical Specification Bases2020-12-22022 December 2020 Submittal of Changes to the Seabrook Station Technical Specification Bases SBK-L-20149, Response to Request for Additional Information in Respect to One-Time Exemption from 10 CFR 73, Appendix B, Section VI, Subsection C.3.(I)(1) Regarding Annual Force-on-Force (FOF) Exercises, Due to Covid 19 Pandemic2020-12-0808 December 2020 Response to Request for Additional Information in Respect to One-Time Exemption from 10 CFR 73, Appendix B, Section VI, Subsection C.3.(I)(1) Regarding Annual Force-on-Force (FOF) Exercises, Due to Covid 19 Pandemic SBK-L-20146, One-Time Exemption Request for the Biennial Emergency Preparedness Exercise Requirements of 10 CFR 50, Appendix E. IV.F.2.b and IV.F.2.c2020-12-0303 December 2020 One-Time Exemption Request for the Biennial Emergency Preparedness Exercise Requirements of 10 CFR 50, Appendix E. IV.F.2.b and IV.F.2.c SBK-L-20144, Request for a One-Time Exemption from 10 CFR 73, Appendix B, Section VI Subsection C.3.(1)(1) Regarding Annual Force-on-Force (FOF) Exercises, Due to Covid 19 Pandemic2020-11-23023 November 2020 Request for a One-Time Exemption from 10 CFR 73, Appendix B, Section VI Subsection C.3.(1)(1) Regarding Annual Force-on-Force (FOF) Exercises, Due to Covid 19 Pandemic SBK-L-20143, Withdrawal of Exemption Request Supporting Updated Final Response to NRC Generic Letter 004-022020-11-19019 November 2020 Withdrawal of Exemption Request Supporting Updated Final Response to NRC Generic Letter 004-02 SBK-L-20132, Fourth Interval Inservice Testing (IST) Program2020-10-21021 October 2020 Fourth Interval Inservice Testing (IST) Program SBK-L-20127, Generator Tube Inspection Report2020-10-20020 October 2020 Generator Tube Inspection Report SBK-L-20117, Response to Request for Additional Information Regarding Technical Specification 3/4.8.1 for a One-Time Extension of Allowed Outage Time License Amendment Request2020-09-23023 September 2020 Response to Request for Additional Information Regarding Technical Specification 3/4.8.1 for a One-Time Extension of Allowed Outage Time License Amendment Request SBK-L-20103, Inservice Inspection Examination Report2020-07-27027 July 2020 Inservice Inspection Examination Report SBK-L-20092, Response to Request for Additional Information Regarding License Amendment Requests to Adopt TSTF-411 and TSTF-4182020-07-13013 July 2020 Response to Request for Additional Information Regarding License Amendment Requests to Adopt TSTF-411 and TSTF-418 SBK-L-20068, License Amendment Request 20-01, One-Time Change to the Seabrook Technical Specifications A.C. Sources - Operating2020-07-13013 July 2020 License Amendment Request 20-01, One-Time Change to the Seabrook Technical Specifications A.C. Sources - Operating SBK-L-20085, Supplement to Exemption Request for Access Authorization and Fitness for Duty Requirements Due to COVID-19 Pandemic2020-06-16016 June 2020 Supplement to Exemption Request for Access Authorization and Fitness for Duty Requirements Due to COVID-19 Pandemic SBK-L-20077, Core Operating Limits Report for Cycle 212020-06-0101 June 2020 Core Operating Limits Report for Cycle 21 SBK-L-20057, Response to Request for Additional Information Regarding Degraded Voltage Time Delay Setpoint License Amendment Request2020-05-20020 May 2020 Response to Request for Additional Information Regarding Degraded Voltage Time Delay Setpoint License Amendment Request 2023-06-22
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NExTera ENERGY G February 25, 2015 10 CFR 50.90 SBK-L-15036 Docket No. 50-443 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Seabrook Station Response to Request for Additional Information for License Amendment Request 11-04, Changes to Technical Specifications for New Fuel Vault
References:
- 1. Seabrook Station License Amendment Request 11-04, "Changes to the Technical Specifications for New and Spent Fuel Storage," SBK-L- 11245, January 30, 2012 (ML12038A036).
- 2. NRC letter to Seabrook Station, "Seabrook Station, Unit No. I.- Supplemental Information Needed for Acceptance of Requested Licensing Action Regarding License Amendment Request 11-04, Change to Technical Specifications for New and Spent Fuel Storage (TAC No. ME7946)," March 30, 2012 (ML120730270).
- 3. Seabrook letter to NRC, "Supplement to LAR 11-04, Changes to the Technical Specifications 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 Letter Regarding License Amendment Request 11-04, Changes to Technical Specifications for New and Spent Fuel Storage (TAC No. ME8688)," June 19, 2012.
- 5. NRC letter to Seabrook Station, "Seabrook Station, Unit No. 1 - Request for Additional Information Regarding License Amendment Request 11-04, Changes to Technical Specifications for New and Spent Fuel Storage (TAC No. ME8688)," July 24, 2012 (ML12192A232).
- 6. Seabrook letter to NRC, "Response to Request for Additional Information Regarding License Amendment Request 11-04, Changes to Technical Specifications for New and Spent Fuel Storage," SBK-L- 12199, September 20, 2012 (ML12271A276).
NeBfa NextEra Energy Seabrook, LLG, P.O. Box 300, Lafayette Road, Seabrook, NHl 03874
U.S. Nuclear Regulatory Commission SBK-L-15036/Page 2
- 7. NRC letter to Seabrook Station, "Seabrook Station, Unit No. 1 - Request for Additional Information Regarding License Amendment Request 11-04, Changes to Technical Specifications 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 Information Regarding License Amendment Request 11-04, Changes to Technical Specifications for New and Spent Fuel Storage," SBK-L- 13061, March 27, 2013 (ML13099A022).
- 9. Seabrook letter to NRC, "Request for Review and Approval of License Amendment Request (LAR) 11-04, Changes to Technical Specifications for New and Spent Fuel Storage, in Two Parts," SBK-L- 13224, December 20, 2013(ML13360A645).
- 10. NRC letter to Seabrook Station, "Seabrook Station, Unit No. I - Request for Additional Information for License Amendment Request 11-04, Changes to Technical Specifications for Spent Fuel Storage (TAC No. ME8688)," January 8, 2014.
- 11. NRC letter to Seabrook Station, "Seabrook Station, Unit No. I - Request for Additional Information for License Amendment Request 11-04, Changes to Technical Specifications for New Fuel Vault (TAC No. MF3283)," January 8, 2014 (ML13268A468).
- 12. Seabrook letter to NRC, "Response to Request for Additional Information for License Amendment 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 License Amendment 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 Amendment Regarding License Amendment Request Regarding Fuel Storage Changes (TAC No.
ME8688)," September 3, 2014 (ML14184A795).
- 15. NRC letter to Seabrook Station, "Seabrook Station, Unit No. 1 - Request for Additional Information for License Amendment Request 11-04, Changes to Technical Specifications for New Fuel Vault (TAC No. MF3283)," October 20, 2014 (ML14276A207).
In Reference 1, NextEra Energy Seabrook, LLC (NextEra) submitted License Amendment Request (LAR) 11-04 to the Technical Specifications (TS) for Seabrook Station. The proposed change would revise the TS for new and spent fuel storage as the result of new criticality analyses for the new fuel vault and the spent fuel pool.
In Reference 2, the NRC requested supplemental information to support acceptance of the LAR 11-04. NextEra supplied the information requested in Reference 3. In Reference 4, the NRC accepted 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 Commission SBK-L-15036/Page 3 In Reference 7, the NRC transmitted their second Request for Additional information on LAR 11-04. NextEra supplied the information requested in Reference 8.
In Reference 9, NextEra requested that the spent fuel storage and new fuel vault segments of LAR 11-04 be treated separately, so that approval of the spent fuel storage segment would not be delayed 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 NRC transmitted their fourth Request for Additional information on LAR 11-04 with questions on the new fuel vault segment. NextEra supplied the information requested for the spent fuel pool in Reference 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 below in the enclosure to this letter. This response does not modify the changes to the TS as previously proposed and does not alter the conclusion in Reference 1 that the changes do not present a significant 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, LLC Dean Curtland Site Vice President Enclosure
U.S. Nuclear Regulatory Commission SBK-L-15036/Page 4 cc: D. Dorman, NRC Region I Administrator J. Lamb, NRC Project Manager, Project Directorate 1-2 P. Cataldo, NRC Senior Resident Inspector Mr. Perry Plummer Director Homeland Security and Emergency Management New Hampshire Department of Safety Division of Homeland Security and Emergency Management Bureau of Emergency Management 33 Hazen Drive Concord, NH 03305 John Giarrusso, Jr., Nuclear Preparedness Manager The Commonwealth of Massachusetts
-Emergency Management Agency 400 Worcester Road Framingham, MA 01702-5399
ENCLOSURE Response 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 Vault NRC Question 1. Was there a basis for the 0.4 weight percent hydrogen used as the lower limit in the NFV concrete?
Response
The Seabrook New Fuel Vault (NFV) concrete was constructed with a 3000 psi concrete mixture, consisting of ASTM C 150, Type II Portland cement with a maximum water to cement ratio of 0.50. The course aggregate of the Seabrook NFV concrete is composed of particles of meta-igneous and meta-quartzite rock, while the fine aggregate is primarily made up with quartz with lesser amounts of feldspar, micaceous minerals, chelt, granite, and sand-sized particles of the coarse aggregate. In addition, no fly ash is found in the Seabrook NFV concrete. That concrete composition has a Hydrogen content of 1.0 weight percent. This information on the Seabrook 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 Dry concrete, with 0.4 weight percent Hydrogen. Sensitivity analyses performed and documented in the aforementioned previous RAI response noted that the NFV's reactivity for the optimum moderation case increased when decreasing the Hydrogen content, with negligible impacts for other isotopes or for all isotopes for the fully flooded case. Therefore, the Hanford Dry composition was used in the model as it had a considerably lower Hydrogen content, thus bounding the reactivity calculated with the actual concrete composition.
Reference 1.1 Seabrook letter to NRC, "Response to December 2012 Request for Additional Information Regarding License Amendment Request 11-04, Changes to Technical Specifications for New 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 the chemical reaction between water and cement. The hydrogen content of concrete decreases from the time of placement due to evaporative losses. However, concrete with a hydrogen content of 1.0% 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 cement hydration products and is not lost on drying. For typical portland cement, the chemical reaction resulting in hydration of the cement requires about 1 part (by weight) water for every 4 parts cement (Reference 2.2).
" Interlayer Water - This water is strongly hydrogen bound between layers of hydration products. 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 to the surface by hydrogen bonding. A major portion of the adsorbed water may be lost when hydrated 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 with hydration products. Evaporation of capillary water starts to occur when ambient relative humidity is less than 100 percent.
As discussed in the response to question 1, the concrete mix from the NFV has a maximum water-to-cement ratio of 0.5 (i.e., 2 parts water for every 4 parts cement). Because hydration of cement requires about 1 part water for every 4 parts cement, half of the original water content of the 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 chemically bound water is 0.5%. This hydrogen content exceeds the 0.4% hydrogen used in the criticality analyses.
The actual hydrogen content in the concrete will include more than only the chemically bound hydrogen because the interlayer water, adsorbed water, and a portion of the original capillary water will remain in the concrete. The atmospheric conditions at Seabrook Station are sufficiently humid to limit evaporative losses. The National Oceanic and Atmospheric Administration (NOAA) tracks weather data at its monitoring station in Concord, New Hampshire (Reference 2.3). Data for average relative humidity from 1965 to 2012 show an average daily high of 80% and an average daily low of 53%. The least humid month (April) has an average daily low humidity of 44%, which would be the minimum humidity present in the concrete pores. Atmospheric humidity is not low enough to cause evaporation of interlayer water and adsorbed water.
References 2.1 Mehta, P. and Monteiro, P., "Concrete: Microstructure, Properties, and Materials," Fourth Edition. 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 and Atmospheric Administration. Retrieved on February 19, 2015 from website http://wwwl .ncdc.noaa.gov/pub/data/ccd-data/CCD-2012.pdf