NL-16-195, Watts Bar, Units 1 and 2 - Spent Fuel Pool Evaluation Supplemental Report - Response to NRC Request for Information, Regarding Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident: Difference between revisions

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#REDIRECT [[CNL-16-195, Watts Bar, Units 1 and 2 - Spent Fuel Pool Evaluation Supplemental Report - Response to NRC Request for Information, Regarding Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident]]
| number = ML16357A578
| issue date = 12/22/2016
| title = Watts Bar, Units 1 and 2 - Spent Fuel Pool Evaluation Supplemental Report - Response to NRC Request for Information, Regarding Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident
| author name = Shea J W
| author affiliation = Tennessee Valley Authority
| addressee name =
| addressee affiliation = NRC/Document Control Desk, NRC/NRR
| docket = 05000390, 05000391
| license number = CPPR-092, NPF-090
| contact person =
| case reference number = CNL-16-195, TAC MF3769
| document type = Letter type:NL, Response to Request for Additional Information (RAI)
| page count = 6
| project = TAC:MF3769
| stage = Response to RAI
}}
 
=Text=
{{#Wiki_filter:, 1101 Market Street, Chattanooga, Tennessee 37402
 
CNL-16-195  
 
December 22, 2016
 
10 CFR 50.4 10 CFR 50.54(f)
 
ATTN: Document Control Desk U.S. Nuclear Regulatory Commission  Washington, D.C. 20555-0001 Watts Bar Nuclear Plant, Units 1 and 2 Facility Operating License Nos. NPF-90 and NPF-96 NRC Docket Nos. 50-390 and 50-391
 
==Subject:==
: 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 Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident," dated March 12, 2012 (ML12053A340)
: 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, (ML15194A015)
: 3. NEI letter to NRC, "Request for Endorsement of Seismic Evaluation Guidance: Spent Fuel Pool Integrity Evaluation (EPRI 3002007148),"
dated February 23, 2016 (ML16055A017)
: 4. EPRI 3002007148, "Seismic Evaluation Guidance, Spent Fuel Pool Integrity Evaluation," dated February 2016 (ML16055A021)
 
U.S. Nuclear Regulatory Commission CNL-16-195
 
Page 2 December 22, 2016
: 5. NRC letter to NEI, "Endorsement of Electrical Power Research Institute Report 3002007148, Seismic Evaluation Guidance:  Spent Fuel Pool Integrity Evaluation," dated March 18, 2016 (ML15350A158)
: 6. TVA letter to NRC, "Tennessee Valley Authority's Seismic Hazard and Screening Report (CEUS Sites), Response to NRC Request for  
 
Information Pursuant to 10 CFR 50.54(f) Regarding Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident," dated March 31, 2014 (ML14098A478)
: 7. NRC letter to TVA, "Watts Bar Nuclear Plant, Unit 1 - Staff Assessment of Information provided Pursuant to Title 10 of the Code of Federal Regulations, Section 50.54(f), Seismic Hazard Reevaluations Relating to Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima DAI-ICHI Accident (TAC No. MF3769)," dated
 
October 5, 2015 (ML15055A543)
: 8. NRC letter to TVA, "Watts Bar Nuclear Plant, Unit 2 - Staff Assessment of Information provided Pursuant to Title 10 of the Code of Federal Regulations, Section 50.54(f), Seismic Hazard Reevaluations Relating to Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima DAI-ICHI Accident (TAC No. MF3769)," dated
 
October 5, 2015 (ML15111A377)
: 9. EPRI 1025287, "Seismic Evaluation Guidance, Screening, Prioritization and Implementation Details [SPID] for the Resolution of Fukushima
 
Near-TermTask Force Recommendation 2.1: Seismic," dated February2013 (ML12333A170)
On March 12, 2012, the Nuclear Regulatory Commission (NRC) issued a Request for Information pursuant to Title 10 of the Code of Federal Regulations (CFR) Part 50.54(f) (Reference 1) to all power reactor licensees. Enclosure 1, Item (9) of the 50.54(f) letter requested addressees to provide limited scope spent fuel pool (SFP) evaluations. By letter dated October 27, 2015 (Reference 2), the NRC transmitted final seismic information request tables which identified that Watts Bar Nuclear Plant is to conduct a limited scope SFP Evaluation. Watts Bar Nuclear Plant, Units 1 and 2, share a common SFP. In Reference 3, the Nuclear Energy Institute (NEI) submitted the Electric Power Research Institute (EPRI) report, "Seismic Evaluation Guidance Spent Fuel Pool Integrity Evaluation (EPRI 3002007148)," (Reference 4) for NRC review and endorsement. NRC endorsement of EPRI 3002007148 was provided by Reference 5. EPRI 3002007148 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 in the Seismic Evaluation Guidance, Screening, Prioritization and Implementation Details (SPID) (Reference 9), for plants where the GMRS peak spectral 
 
E-1 E-2 The 50.54(f) letter requested that, in conjunction with the response to NTTF Recommendation 2.1, a seismic evaluation be made of the SFP. More specifically, plants were asked to consider "-all seismically induced failures that can lead to draining of the SFP."  Such an evaluation would be needed for any plant in which the ground motion response spectrum (GMRS) exceeds the safe shutdown earthquake (SSE) in the 1 to 10 Hz frequency range. The staff confirmed through References 2 and 7 that the GMRS exceeds the SSE and concluded that a SFP evaluation is merited for Watts Bar Nuclear Plant. By letter dated March 18, 2016 (Reference 5),
the staff determined that EPRI 3002007148 was an acceptable approach for performing SFP evaluations for plants where the peak spectral acceleration is less than or equal to 0.8g. The table below lists the criteria from Section 3.3 of EPRI 3002007148 along with data for Watts Bar Nuclear Plant that confirms applicability of the EPRI 3002007148 criteria and confirms that the SFP is seismically adequate and can retain adequate water inventory for 72 hours in accordance with NTTF 2.1 Seismic evaluation criteria. 1. The site-specific GMRS peak spectral acceleration at any frequency should be less than or equal to 0.8g. The GMRS peak spectral acceleration submitted
 
for Watts Bar Nuclear Plant GMRS (Reference 6), and accepted by the NRC in the Staff Assessment letters (References 7 & 8) is 0.766g, which is 0.8g. Therefore, this criterion is met. 2. The structure housing the SFP should be designed using an SSE with a peak ground acceleration (PGA) of at least 0.1g. The SFP is housed in the Auxiliary Building, which is seismically designed to the site SSE with a PGA of 0.18g. The Watts Bar Nuclear Plant PGA is greater than 0.1g. Therefore, this criterion is met. 3. The structural load path to the SFP should consist of some combination of reinforced concrete shear wall elements, reinforced concrete frame elements, post-tensioned concrete elements and/or structural steel frame elements. The structural load path from the foundation to the SFP consists of reinforced concrete shear walls and a reinforced concrete pool bottom that is built integrally with the Auxiliary Building. Therefore, this criterion is met for Watts Bar Nuclear Plant. 4. The SFP structure should be included in the Civil Inspection
 
Program performed in accordance with Maintenance Rule. The SFP structure is included in the Watts Bar Nuclear Plant Civil Inspection Program in accordance with 10 CFR 50.65, which monitors the performance or condition of structures, systems, or components (SSCs) in a manner sufficient to provide reasonable assurance that these SSCs are capable of fulfilling their intended functions.
Therefore, this criterion is met for Watts Bar Nuclear Plant.
 
E-3  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.
Piping attached to the SFP is evaluated to the SSE in accordance with the Updated Final Safety Analysis Report (UFSAR). Therefore, this criterion is met for Watts Bar Nuclear Plant. 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. Design provisions are in place to protect against significant water loss. The SFP cooling system suction connections enter near normal water level so that the SFP cannot be siphoned. SFP skimmer pump suction and discharge piping are also located near normal water level. The 10" SFP cooling water return line is truncated approximately 2.5 feet below normal water level. All cooling water return lines contain an anti-siphon hole to prevent any significant loss of water from the SFP. In addition, an anti-siphon valve is located in transfer canal drain line to prevent draining the SFP when the transfer canal is open. As described, anti-siphoning devices are installed on all SFP piping that could lead to siphoning.
Therefore, this criterion is met for Watts Bar
 
Nuclear Plant. As described, no anti-siphoning devices are attached to 2-inch or smaller piping with extremely large extended operators. Therefore, this criterion is met for Watts Bar Nuclear Plant. 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 125 ft, the SFP depth should be greater than 36 ft, and the GMRS peak Sa should be <0.1g at frequencies equal to or less than 0.3 Hz. The Watts Bar Nuclear Plant SFP has a length of 39.5 ft, a width of 31.7 ft, and a depth of 47.9 ft based on Watts Bar Nuclear Plant UFSAR.
Therefore, this criterion is met.
The Watts Bar Nuclear Plant GMRS maximum spectral acceleration in the frequency range equal to or less than 0.3 Hz is 0.046g from Watts Bar Nuclear Plant GMRS submittal which is less than 0.1g. Therefore, this criterion is 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 500 ft 2 and the licensed reactor core thermal power should be less than 4,000 MWt per unit. The surface area of the Watts Bar Nuclear Plant SFP is approximately 1250 ft 2 , which is greater than 500 ft 2; and licensed reactor thermal power for Watts Bar Nuclear Plant Unit 1 is 3,459 MWt and Unit 2 is 3,411 MWt which is less than 4,000 MWt per unit. Therefore, this criterion are met for both Units 1 and 2.}}

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