ML16041A341
| ML16041A341 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 02/29/2016 |
| From: | Victor Hall Japan Lessons-Learned Division |
| To: | Heacock D Virginia Electric & Power Co (VEPCO) |
| Hall, Victor NRR/JLD 415-2915 | |
| References | |
| CAC MF6102, CAC MF6103 | |
| Download: ML16041A341 (8) | |
Text
OFFICIAL USE ONLY SECURITY RELATED INFORMATION UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 February 29, 2016 Mr. David A. Heacock President and Chief Nuclear Officer Virginia Electric and Power Company 5000 Dominion Blvd.
Glen Allen, VA 23060-6711
SUBJECT:
SURRY POWER STATION, UNIT NOS. 1 AND 2 - INTERIM STAFF RESPONSE TO REEVALUATED FLOOD HAZARDS SUBMITTED IN RESPONSE TO 10 CFR 50.54(f) INFORMATION REQUEST- FLOOD-CAUSING MECHANISM REEVALUATION (CAC NOS. MF6102 AND MF6103)
Dear Mr. Heacock:
The purpose of this letter is to provide a summary of the U.S. Nuclear Regulatory Commission (NRC) staff's assessment of the reevaluated flood-causing mechanisms described in the March 12, 2015 (Agencywide Documents Access and Management System (ADAMS)
Accession No. ML15078A291 ), flood hazard reevaluation report (FHRR) submitted by Virginia Electric and Power Company (the licensee) for Surry Power Station, Unit Nos. 1 and 2 (Surry),
as well as supplemental information resulting from requests for additional information and audits.
By letter dated March 12, 2012, the NRC issued a request for information pursuant to Title 10 of the Code of Federal Regulations, Section 50.54(f) (hereafter referred to as the 50.54(f) letter)
(ADAMS Accession No. ML12053A340). The request was issued as part of implementing lessons-learned from the accident at the Fukushima Dai-ichi nuclear power plant. Enclosure 2 to the 50.54(f) letter requested licensees to re-evaluate flood-causing mechanisms using present-day methodologies and guidance. Concurrently with the reevaluation of flooding hazards, licensees were required to develop and implement mitigating strategies in accordance with NRC Order EA-12-049, "Requirements for Mitigation Strategies for Beyond-Design-Basis External Events" (ADAMS Accession No. ML12054A735). On March 30, 2015, the Commission provided Staff Requirements Memoranda (SRM) (ADAMS Accession No. ML15089A236) to COMSECY-14-0037, "Integration of Mitigating Strategies for Beyond-Design-Basis External Events and the Reevaluation of Flooding Hazards," dated November 21, 2014 (ADAMS Accession No. ML14309A256), affirming that licensees need to address the reevaluated flooding hazards within their mitigating strategies for beyond-design-basis external events.
Enclosure two transmitted herewith contains Security-Related Information. When separated from the Enclosure, this document is decontrolled.
OFFICIAL USE ONLY SECURITY RELATED INFORMATION
OFFICIAL USE ONLY SECURITY RELATED INFORMATION D. Heacock The NRC staff has reviewed the information submitted by the licensee and has summarized the results of the review in the tables provided as Enclosure 1 to this letter. Table 1 provides the current design-basis flood hazard mechanisms. Table 2 provides reevaluated flood hazard mechanisms; however, reevaluated hazard mechanisms bounded by the current design-basis (Table 1) are not included. Because Table 2 includes security-related information, Enclosure 1 contains the redacted version of Table 2. Enclosure 2 is withheld from public disclosure and restores the security-related information to Table 2.
The NRC staff has concluded that the licensee's reevaluated flood hazards information, as summarized in the Enclosure, is suitable for the assessment of mitigating strategies developed in response to Order EA-12-049 (i.e., defines the mitigating strategies flood hazard information described in Nuclear Energy Institute (NEI) guidance document NEI 12-06, "Diverse and Flexible Coping Strategies (FLEX) Implementation Guide") for Surry. Further, the NRC staff has concluded that the licensee's reevaluated flood hazard information is a suitable input for other assessments associated with Near-Term Task Force Recommendation 2.1 "Flooding". The NRC staff plans to issue a staff assessment documenting the basis for these conclusions at a later time.
Revision 2 of NEI 12-06 includes a methodology to perform a Mitigating Strategies Assessment (MSA) with respect to the reevaluated flood hazards. On February 29, 2016, the NRC staff published Japan Lessons-Learned Division Interim Staff Guidance (ISG) JLD-ISG-2012-01, Revision 1, "Compliance with Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events," (ADAMS Accession No. ML15357A142) in the Federal Register. This ISG endorses Revision 2 of NEI 12-06 (ADAMS Accession No. ML16005A625}, dated December 2015. Based on the guidance provided in Revision 2 of the NEI 12-06 guidance document, flood event duration parameters and applicable flood associated effects should be considered as part of the Surry MSA. The NRC staff will evaluate the flood event duration parameters (including warning time and period of inundation) and flood-related associated effects developed by the licensee during the NRC staff's review of the MSA.
As stated above, Table 2 of the enclosure to this letter describes the reevaluated flood hazards that exceed the current design-basis. In order to complete its response to the information requested by Enclosure 2 to the 50.54(f) letter, the licensee is expected to submit an integrated assessment or a focused evaluation, as appropriate, to address these reevaluated flood hazards, as described in the NRC letter, "Coordination of Request for Information Regarding Flooding Hazard Reevaluation and Mitigating Strategies for Beyond-Design-Basis External Events" (ADAMS Accession No. ML15174A257). This letter describes the changes in the NRC's approach to the flood hazard reevaluations that were approved by the Commission in its SRM to COMSECY-15-0019, "Closure Plan for the Reevaluation of Flooding Hazards for Operating Nuclear Power Plants" (ADAMS Accession No. ML15209A682).
OFFICIAL USE ONLY SECURITY RELATED INFORMATION
OFFICIAL USE ONLY SECURITY RELATED INFORMATION D. Heacock If you have any questions, please contact me at (301) 415-2915 or e-mail at Victor.Hall@nrc.gov.
Sincerely,
'!J~l' Victor Hall, Senior Project Manager Hazards Management Branch Japan Lessons-Learned Division Office of Nuclear Reactor Regulation Docket Nos. 50-280 and 50-281 Enclosures
- 1. Summary of Results of Flooding Hazard Re-Evaluation Report (Redacted Version)
- 2. Summary of Results of Flooding Hazard Re-Evaluation Report (Non-Public Version) cc w/encl: Distribution via Listserv OFFICIAL USE ONLY SECURITY RELATED INFORMATION
ENCLOSURE:
SUMMARY
TABLES OF REEVALUATED FLOOD HAZARD LEVELS
Surry Power Station, Units 1 & 2 Table 1. Current Design Basis Flood Hazards for Use in the MSA Mechanism Stillwater Waves/ Design Basis Reference Elevation Run up Hazard
.................______ Elevation Local Intense Precipitation Not included Not included Not included FHRR Table 3.0-1 in DB in DB in DB Streams and Rivers No Impact No Impact No Impact FHRR Table 3.0-1 on the Site on the Site on the Site Identified Identified Identified Failure of Dams and Onsite Water Control/Storage Structures No Impact No Impact No Impact FHRR Table 3.0-1 on the Site on the Site on the Site Identified Identified Identified
---*--****-***--*-*****----------*----*------+-----**-----**--***--*---+*-------**--********--*--+---***-****---***----**-------*--*-**---*-**-**---------*----------*-
Storm Surge PMH Flooding West Side 22.7 MSL 1.3 ft 24.0 MSL FHRR Section 3.9 PMH Flooding East Side 22.7 MSL 5.9 ft 28.6 MSL FHRR Section 3.9 Seiche No Impact No Impact No Impact FHRR Table 3.0-1 on the Site on the Site on the Site Identified Identified Identified Tsunami No Impact No Impact No Impact FHRR Table 3.0-1 on the Site on the Site on the Site Identified Identified Identified Ice-Induced Flooding Not included Not included Not included FHRR Table 3.0-1 in DB in DB in DB
Surry Power Station, Units 1 & 2 Table 1. Current Design Basis Flood Hazards for Use in the MSA Mechanism Stillwater Waves/ Basis Reference Elevation Run up Hazard Elevation Channel Migrations/Diversions I
Not included ! Not included Not included FHRR Table 3.0-1 in DB in DB in DB
- +*******************-****************** ************** ************---------*****-----------***********---....
Note 1: Reported values are rounded to the nearest one-tenth of a foot.
Surry Power Station, Units 1 & 2 Table 2. Reevaluated Flood Hazards for Flood-Causing Mechanisms for Use in the MSA
~r---
Mechanism Elevation Stillwater Waves/
Runup
~-----------------
Reevaluated Hazard Reference I
[
Elevation I Local Intense Precipitation Site-specific PMP 29.4 MSL Minimal 29.4 MSL FHRR Table 3.0-1 and Section 2.1.4 i
I I
! I i J _ ________ J I I
Failure of Darns and Onsite I I Water Control/Storage I I I
Structures I I !
[Redacted] [Redacted] [Redacted] j [Redacted] I [Redacted] I I
I
-1 Deterministic PMSS with James 24.2 MSL 14.6 ft 38.8 MSL FHRR Section 2.9-7 River 25-year Flood, East Side of Plant, Low Level Intake Structure Deterministic PMSS with James 24.2 MSL Minimal 24.2 MSL FHRR Table 2.9-4, FHRR Section River 25-year Flood, West Side 2.9.2.2, and FHRR Section 2.9.1.1 of Plant Note 1: The licensee is expected to develop flood event duration parameters and applicable flood associated effects to conduct the MSA. The staff will evaluate the flood event duration parameters (including warning time and period of inundation) and flood associated effects during its review of the MSA.
Note 2: Reevaluated hazard mechanisms bounded by the current design basis (see Table 1) are not included in this table Note 3: Reported values are rounded to the nearest one-tenth of a foot.
Note 4: Onsite Structure Failure flood causing mechanism elevations are reported as the highest elevations at specific door locations; it appears from the FHRR that the licensee may intend to specify a different flood elevation for each door, based on model output.
PKG ML16041A332 LTR: ML16041A341 ENCL 1: ML16049A542 ENCL2: ML16049A534 *via email OFFICE NRR/JLD/JHMB/PM NRR/JLD/LA NRO/DSEA/RHM2/TR* NRO/DSEA/RHM2/TR*
NAME VHall SLent NTiruneh LHibler DATE 02/09/16 02/10/16 02/18/16 02/18/16 OFFICE NRO/DSEA/RHM2/BC* NRR/JLD/JHMB/BC NRR/JLD/JHMB/PM NAME ARivera-Varona MShams VHall DATE 02/18/16 02/22/16 02/29/16