ML16365A032

Millstone, Units 2 and 3 - Response to March 12, 2012 Information Request, Spent Fuel Pool Seismic Evaluation for Recommendation 2.1

ML16365A032
Person / Time
Site:	Millstone
Issue date:	12/21/2016
From:	Heacock D A Dominion Nuclear Connecticut
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
16-427, TAC MF3968, TAC MF3969
Download: ML16365A032 (12)

Text

Dominion Nuclear Connecticut, Inc. 5000 Dominion Boulevard, Glen Allen, VA 23060 Web Address: www.dom.com December 21, 2016 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 DOMINION NUCLEAR CONNECTICUT, INC. MILLSTONE POWER STATION UNITS 2 AND 3 Serial No.16-427 NRA/DEA RO Docket Nos. 50-336/423 License Nos. DPR-65 NPF-49 RESPONSE TO MARCH 12, 2012 INFORMATION REQUEST SPENT FUEL POOL SEISMIC EVALUATION FOR RECOMMENDATION 2.1 References: 1. NRC Letter, "Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Recommendations 2.1, 2.3, and 9.3, of the Term Task Force Review of Insights from the Fukushima Dai-ichi Accident," dated March 12, 2012 [ADAMS Accession Nos. ML 12056A046 and ML 12053A340]. 2. NRC Letter, "Final Determination of Licensee Seismic Probabilistic Risk Assessments Under the Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Recommendation 2.1 "Seismic" of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident," dated October 27, 2015 [ADAMS Accession No. ML 15194A015]. 3. EPRI Report 3002007148, Seismic Evaluation Guidance Spent Fuel Pool Integrity Evaluation, February 2016. 4. Dominion Nuclear Connecticut, Inc. Letter, "Millstone Power Station Units 2 and 3, Response to March 12, 2012 Information Request -Seismic Hazard and Screening Report (CEUS Sites) for Recommendation 2.1," dated March 31, 2014 [ADAMS Accession No. ML 14092A417]. 5. NRC Letter, "Millstone Power Station, Units 2 and 3 -Staff Assessment of Information Provided Pursuant to Title 10 of the Code of Federal Regulations Part 50, Section 50.54(f), Seismic Hazard Reevaluations for Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident (TAC Nos. MF3968 and MF3969)," dated December 15, 2015 [ADAMS Accession No. ML 15328A268]. 6. EPRI Report 1025287, Seismic Evaluation Guidance: Screening, Prioritization and Implementation Details (SPID) for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic, February 2013 [ADAMS Accession No. ML 12333A 170]. On March 12, 2012, the Nuclear Regulatory Commission (NRC) issued Reference 1 to all power reactor licensees and holders of construction permits in active or deferred status. Enclosure 1, Item (9), of Reference 1 requested each addressee to provide spent fuel pool (SFP) seismic evaluations. By letter dated October 27, 2015 (Reference ;4 pl D ;Jt-f.-

Serial No.16-427 Docket Nos. 50-336/423 Page 2 of 3 2), the NRC transmitted final seismic information request tables, which identified that Millstone Units 2 and 3 were to conduct a limited scope seismic evaluation that included a SFP evaluation. Electric Power Research Institute (EPRI) Report 3002007148, Seismic Evaluation Guidance Spent Fuel Pool Integrity Evaluation (Reference 3), provides criteria for evaluating the seismic adequacy of a SFP to the reevaluated ground motion response spectrum (GMRS) hazard levels. This report supplements the guidance provided in the Seismic Evaluation Guidance Screening, Prioritization and Implementation Details (SPID) (Reference 6) for plants where the GMRS peak spectral acceleration is less than or equal to 0.8g. Section 3.3 of EPRI Report 3002007148 lists the parameters to be verified to confirm the results of the report are applicable to Millstone Units 2 and 3 in order to conclude that the SFPs are seismically adequate in accordance with Term Task Force (NTTF) Recommendation 2.1: Seismic evaluation criteria. Attachments 1 and 2 provide data for Millstone Power Station Units 2 and 3, respectively, which confirm the applicability of the EPRI Report 3002007148 criteria and confirm that each unit's SFP is seismically adequate. The attachments also provide the information requested in response to Enclosure 1, Item (9) of Reference 1 for Millstone Units 2 and 3. If you have any questions regarding this information, please contact Diane E. Aitken at (804) 273-2694. Sincerely, .\::>wW David A. Heacock President Dominion Nuclear COMMONWEALTH OF VIRGINIA COUNTY OF HENRICO The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by David A. Heacock, who is President Dominion Nuclear of Dominion Nuclear Connecticut, Inc. He has affirmed before me that he is duly authorized to execute and file the foregoing document in behalf of that company, and that the statements in the document are true to the best of his knowledge and belief. Acknowledged before me this st day of , 2016. My Commission Expires: --'-12.=+\ /c..::a-:.....0 _________ _ CRAIG D SLY Notary Public Commonwealth of Virginia Reg.# 7518653 My Commission Expires December 31, Serial No.16-427 Docket Nos. 50-336/423 Page 3 of 3 Commitments made in this letter: No new regulatory commitments. Attachments: 1. Spent Fuel Pool Data for Millstone Unit 2 2. Spent Fuel Pool Data for Millstone Unit 3 cc: U.S. Nuclear Regulatory Commission Region I 2100 Renaissance Blvd Suite 100 King of Prussia, PA 19406-2713 Richard V. Guzman Senior Project Manager U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 08 C 2 11555 Rockville Pike Rockville, MD 20852-2738 NRC Senior Resident Inspector Millstone Power Station 50.54f_Seismic.Resource@nrc.gov . -...

ATTACHMENT 1 Serial No.16-427 Docket No. 50-336 SPENT FUEL POOL DATA FOR MILLSTONE UNIT 2 MILLSTONE POWER STATION UNIT 2 DOMINION NUCLEAR CONNECTICUT, INC.

Spent Fuel Pool Data for Millstone Unit 2 Serial No.16-427 Docket No. 50-336 Attachment 1 Page 2 of 4 NRC Letter, "Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Recommendations 2.1, 2.3, and 9.3, of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident," dated March 12, 2012 (Reference 1 ), Enclosure 1, Item (9), requested each addressee, for which the ground motion response spectrum (GMRS) exceeds the safe shutdown earthquake (SSE) in the 1 to 10 Hz frequency range, to provide a spent fuel pool (SFP) seismic evaluation in response to NTTF Recommendation 2.1: Seismic. Specifically, plants were requested to consider "all seismically induced failures that can lead to draining of the SFP." EPRI Report 3002007148 (Reference 2) provides guidance for the limited scope SFP seismic evaluation. The Millstone Unit 2 SFP has been evaluated consistent with the guidance provided in Reference 2. The table below lists the criteria from Section 3.3 of Reference 2 along with data for Millstone Unit 2 that confirms applicability of the EPRI Report 3002007148 criteria. The table confirms that the SFP is seismically adequate and can retain adequate water inventory for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> in accordance with NTTF 2.1 Seismic evaluation criteria. References: 1. NRC Letter, "Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Recommendations 2.1, 2.3, and 9.3, of the Term Task Force Review of Insights from the Fukushima Dai-ichi Accident," dated March 12, 2012 2. EPRI Report 3002007148, Seismic Evaluation Guidance Spent Fuel Pool Integrity Evaluation, February 2016 3. Dominion Nuclear Connecticut, Inc. Letter, "Millstone Power Station Units 2 and 3, Response to March 12, 2012 Information Request -Seismic Hazard and Screening Report (CEUS Sites) for Recommendation 2.1," dated March 31, 2014 4. NRC Letter, "Millstone Power Station, Units 2 and 3 -Staff Assessment of Information Provided Pursuant to Title 10 of the Code of Federal Regulations Part 50, Section 50.54(f), Seismic Hazard Reevaluations for Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident (TAC Nos. MF3968 and MF3969)," dated December 15, 2015

1. The site-specific GMRS peak spectral acceleration at any frequency should be less than or equal to 0.8g. 2. The structure housing the SFP should be designed using an SSE with a peak ground acceleration (PGA) of at least 0.1 g. 3. The structural load path to the SFP should consist of some combination of reinforced concrete shear wall elements, reinforced concrete frame elements, tensioned concrete elements and/or structural steel frame elements. 4. The SFP structure should be included in the Civil Inspection Program performed in accordance with Maintenance Rule. Serial No.16-427 Docket No. 50-336 Attachment 1 Page 3 of 4 The GMRS peak spectral acceleration in the Seismic Hazard and Screening Report (Reference 3), as accepted by the NRC in the Staff Assessment (Reference 4), is 0.4217g, which is s 0.8g. Therefore, this criterion is met. The SFP is housed in the Auxiliary Building, which is a seismic Category I structure designed to the SSE. Reference 3, Table 3.1.1-1 gives a tabular version of the design spectra. The Millstone Power Station Unit 2 SSE PGA is 0.17g, which is greater than 0.1g. Therefore, this criterion is met. The structural load path from the foundation to the SFP consists of reinforced concrete in moment resistant frames and shear walls. The walls are nominally 72 inches thick with #11 rebar spaced at 9 inches on center. The pool is 42 feet long by 25 feet wide by 41 feet deep with a nominal level of 38 feet of water. The bottom slab is 5 feet thick and reinforcing is #14 rebar at 9 inches on center. Therefore, the structural load path to the SFP consists of reinforced concrete elements and this criterion is met for Millstone Power Station Unit 2. The Auxiliary Building, which contains the SFP, is included in the Condition Monitoring of Structures Program (Civil Inspection Program) performed in accordance with 10 CFR 50.65, Maintenance Rule. Inspections of the structure are intended to ensure long term functionality. Therefore, this criterion is met.

5. To confirm applicability of the piping evaluation in Section 3.2 of EPRI 3002007148, piping attached to the SFP up to the first valve should have been evaluated for the SSE. 6. Anti-siphoning devices should be installed on any piping that could lead to siphoning water from the SFP. In. addition, for any cases where active anti-siphoning devices are attached to 2-inch or smaller piping and have extremely large extended operators, the valves should be walked down to confirm adequate lateral support. 7. To confirm applicability of the sloshing evaluation in Section 3.2 of EPRI 3002007148, the maximum SFP horizontal dimension (length or width) should be less than 125ft, the SFP depth should be greater than 36ft, and the GMRS peak Sa should be < 0.1g at frequencies equal to or less than 0.3Hz. 8. To confirm applicability of the evaporation loss evaluation in Section 3.2 of EPRI 3002007148, the SFP surface area should be greater than 500ft2 and the licensed reactor core thermal power should be less than 4000MWt per unit. Serial No.16-427 Docket No. 50-336 Attachment 1 Page 4 of 4 Piping attached to the SFP, which is part of the SFP cooling system, is seismic Category I up to the first valve and is evaluated to the SSE. Therefore, this criterion is met. Passive anti-siphoning devices are installed on SFP piping that could lead to siphoning of the pool inventory. Additionally, there are no anti-siphoning devices with extremely large extended operators attached to 2-inch or smaller piping. Therefore, this criterion is met. The SFP has a length of 42 feet, a width of 25 feet and a depth of 41 feet with a nominal water level of 38 feet. Therefore, this criterion is met. The Millstone Power Station GMRS maximum spectral acceleration in the frequency range equal to or less than 0.3Hz is 0.02g (Reference 3, Table 2.4-1 ), which is less than 0.1 g. Therefore, this criterion is met. The surface area of the SFP is 1050 ft2, which is greater than 500 ft2. The licensed reactor core thermal power for Millstone Power Station Unit 2 is 2700MWt, which is less than 4000MWt per unit. Therefore, these criteria are met.

ATTACHMENT 2 Serial No.16-427 Docket No. 50-423 SPENT FUEL POOL DATA FOR MILLSTONE UNIT 3 MILLSTONE POWER STATION UNIT 3 DOMINION NUCLEAR CONNECTICUT, INC.

Spent Fuel Pool Data for Millstone Unit 3 Serial No.16-427 Docket No. 50-423 Attachment 2 Page 2 of 5 NRC Letter, "Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Recommendations 2.1, 2.3, and 9.3, of the Near-Term Task Force Review.of Insights from the Fukushima Dai-ichi Accident," dated March 12, 2012 (Reference 1), Enclosure 1, Item (9), requested each addressee, for which the ground 111otion response spectrum (GMRS) exceeds the safe shutdown earthquake (SSE) in the 1 to 10 Hz frequency range, to provide a spent fuel pool (SFP) seismic evaluation in response to NTTF Recommendation 2.1: Seismic. Specifically, plants were requested to consider "all seismically induced failures that can lead to draining of the SFP." EPRI Report 3002007148 (Reference 2) provides guidance for the limited scope SFP. seismic evaluation. The Millstone Unit 3 SFP has been evaluated consistent with the guidance provided in Reference 2. The table below lists the criteria from Section 3.3 of Reference 2 along with data for Millstone Unit 3 that confirms applicability of the EPRI Report 3002007148 criteria. The table confirms that the SFP is seismically adequate and can retain adequate water inventory for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> in accordance with NTTF 2.1 Seismic evaluation criteria. References: 1. NRC Letter, "Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Recommendations 2.1, 2.3, and 9.3, of the Term Task Force Review of Insights from the Fukushima Dai-ichi Accident," dated March 12, 2012 2. EPRI Report 3002007148, Seismic Evaluation Guidance Spent Fuel Pool Integrity Evaluation, February 2016 3. Dominion Nuclear Connecticut, Inc. Letter, "Millstone Power Station Units 2 and 3, Response to March 12, 2012 Information Request -Seismic Hazard and Screening Report (CEUS Sites) for Recommendation 2.1," dated March 31, 2014 4. NRC Letter, "Millstone Power Station, Units 2 and 3 -Staff Assessment of Information Provided Pursuant to Title 10 of the Code of Federal Regulations Part 50, Section 50.54{f), Seismic Hazard Reevaluations for Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident (TAC Nos. MF3968 and MF3969)," dated December 15, 2015

1. The site-specific GMRS peak spectral acceleration at any frequency should be less than or equal to 0.8g. Structural* Parameters. 2. The structure housing the SFP should be designed using an SSE with a peak ground acceleration (PGA) of at least 0.1g. Serial No.16-427 Docket No. 50-423 Attachment 2 Page 3 of 5 The GMRS peak spectral acceleration in the Seismic Hazard and Screening Report (Reference 3), as accepted by the NRC in the Staff Assessment (Reference 4), is 0.4217g, which is ::;; 0.8g. Therefore, this criterion is met. The SFP is housed in the Fuel Building, which is a Seismic Category I structure designed to the SSE. Reference 3, Table 3.1.1-2 gives a tabular version of the design spectra. The Millstone Power Station Unit 3 SSE PGA is 0.17g, which is greater than 0.1g. Therefore, this criterion is met. 3. The structural load path to the The structural load path from the foundation to the SFP should consist of some SFP consists of reinforced concrete in moment GOmbination of reinforced concrete resistant frames and shear walls. The pool walls are shear wall elements, reinforced nominally 72 inches thick with #11 rebar spaced at 12 concrete frame elements, post-inches on center. The pool is 'L' shaped with a tensioned concrete elements maximum length of 52 feet 6 inches and a maximum and/or structural steel frame width of 38 feet, and 41 feet 1 inch deep with a elements. nominal water level of 38 feet. The bottom slab is 8 feet thick and reinforcing is #11 rebar at 12 inches on center. Therefore, the structural load path to the SFP consists of reinforced concrete elements and this criterion is met. 4. The SFP structure should be The Fuel Building, which contains the SFP, is included included in the Civil Inspection Program performed in accordance with Maintenance Rule. in the Condition Monitoring of Structures Program (Civil Inspection Program) performed in accordance with 1 O CFR 50.65, Maintenance Rule. Inspections of the structure are intended to ensure long term functionality. Therefore, this criterion is met.

" .... ,,,.' .. , .. ' ; : ; . ' : , : . ; . '. ; ' : :* . : . : . . .. Serial No.16-427 Docket No. 50-423 Attachment 2 Page 4 of 5 5. To confirm applicability of the Piping attached to the SFP, which is part of the SFP piping evaluation in Section 3.2 of cooling and service water makeup systems, is seismic EPRI 3002007148, piping Category I up to the first valve and is evaluated to the attached to the SFP up to the first SSE. Therefore, this criterion is met. valve should have been evaluated forthe SSE. Passive anti-siphoning devices are installed on SFP piping that could lead, to siphoning of the pool inventory. 6. Anti-siphoning devices should be installed on any piping that could lead to siphoning water from the SFP. In addition, for any cases where active anti-siphoning Additionally, there are no anti-siphoning devices with devices are attached to 2-inch or extremely large extended operators attached to 2-inch smaller piping and have extremely or smaller piping. large extended operators, the valves should be walked down to Therefore, this criterion is met. confirm adequate lateral support. 7. To confirm applicability of the The SFP is 'L' shaped with a maximum length of 52 sloshing evaluation in Section 3.2 feet 6 inches, a maximum width of 38 feet, and a of EPRI 3002007148, the depth of 41 feet, with a nominal water level of 38 feet. maximum SFP horizontal Therefore, this criterion is met. dimension (length or width) should be less than 125ft, the SFP depth The Millstone Power Station GMRS maximum should be greater than 36ft, and spectral acceleration in the frequency range less than the GMRS peak Sa should be < or equal to 0.3Hz is 0.02g (Reference 3, Table 2.4-1), 0.1 g at frequencies equal to or which is less than 0.1 g. Therefore, this criterion is less than 0.3Hz. met.

8. To confirm applicability of the evaporation loss evaluation in Section 3.2 of EPRI 3002007148, the SFP surface area should be greater than 500ft2 and the licensed reactor core thermal power should be less than 4000MWt per unit. Serial No.16-427 Docket No. 50-423 Attachment 2 Page 5 of 5 The surface area of the SFP is approximately 1600 ft2, which is greater than 500 ft2. The licensed reactor thermal power is 3650MWt, which is less than 4000MWt per unit. Therefore, these criteria are met.