ML18291B326
| ML18291B326 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 10/18/2018 |
| From: | Richard Guzman Plant Licensing Branch 1 |
| To: | Sinha S Dominion Energy Nuclear Connecticut |
| Guzman R | |
| References | |
| EPID L-2018-LLA-0126 | |
| Download: ML18291B326 (3) | |
Text
From:
Guzman, Richard Sent:
Thursday, October 18, 2018 4:53 PM To:
'Shayan Sinha' Cc:
'Michael L Whitlock'
Subject:
Millstone Unit 3 - LAR Regarding Proposed Technical Specification Changes for Spent Fuel Pool Storage and New Fuel Storage - REQUEST FOR ADDITIONAL INFORMATION (EPID: L-2018-LLA-0126)
- Shayan, On October 12, 2018, the U.S. Nuclear Regulatory Commission (NRC) staff sent Dominion Energy Nuclear Connecticut, Inc. (DENC, the licensee) the subject Request for Additional Information (RAI) as a draft (via e-mail shown below). This RAI relates to proposed technical specification changes for spent fuel pool storage and new fuel storage for Millstone Power Station, Unit No. 3 (MPS3). You indicated today that a clarification call was not necessary to respond to the information request. I understand DENC will provide a response to this RAI by December 3, 2018.
Updated below is the official (final) RAI. A publicly available version of this e-mail and RAI will be placed in the NRCs ADAMS system. Please contact me should you have any questions in regard to this request.
- Thanks, Rich
~~~~~~~~~
Rich Guzman Sr. PM, Division Operator Reactor Licensing Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Office: O-9C7 l Phone: (301) 415-1030 Richard.Guzman@nrc.gov From: Guzman, Richard Sent: Friday, October 12, 2018 7:33 AM To: 'Michael L Whitlock' <michael.l.whitlock@dominionenergy.com>
Cc: 'Shayan Sinha' <Shayan.Sinha@dominionenergy.com>
Subject:
Millstone Unit 3 - LAR Regarding Proposed Technical Specification Changes for Spent Fuel Pool Storage and New Fuel Storage - DRAFT REQUEST FOR ADDITIONAL INFORMATION (EPID: L-2018-LLA-0126)
- Michael, By letter dated May 3, 2018 (Agencywide Documents Access and Management System Accession No. ML18128A049), Dominion Energy Nuclear Connecticut, Inc. (DENC) submitted a license amendment request regarding proposed technical specification changes for spent fuel storage and new fuel storage in the Millstone Power Station, Unit No. 3 (MPS3) spent fuel pool.
The NRC staff has determined that additional information is needed to complete its review, as described in the request for additional information (RAI) shown below.
This RAI is identified as draft at this time to confirm your understanding of the information that the NRC staff needs to complete the evaluation. Please contact me if you would like to set up a conference call to clarify this request for information. I plan to send the RAI formally by 10/[19].
- Thanks,
~~~~~~~~~
Rich Guzman Sr. PM, Division Operator Reactor Licensing Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Office: O-9C7 l Phone: (301) 415-1030 Richard.Guzman@nrc.gov REQUEST FOR ADDITIONAL INFORMATION LICENSE AMENDMENT REQUEST REGARDING PROPOSED TECHNICAL SPECIFICATIONS CHANGES FOR SPENT FUEL POOL STORAGE AND NEW FUEL STORAGE RACKS MILLSTONE POWER STATION, UNIT 3 DOMINION ENERGY NUCLEAR CONNECTICUT, INC.
DOCKET NO. 50-423 EPID: L-2018-LLA-0126 By letter dated May 3, 2018 (Agencywide Documents Access and Management System Accession No. ML18128A049), Dominion Energy Nuclear Connecticut, Inc. (DENC) submitted a license amendment request for Millstone Power Station, Unit No. 3 (MPS3). DENC performed a criticality safety evaluation for fuel assembly storage in the MPS3 spent fuel pool (SFP) storage racks and new fuel storage racks to support the proposed TS changes using a new methodology. Specifically, the proposed amendment would revise the MPS3 Technical Specification (TSs) supporting changes to the operation and administration of the SFP to (1) modify storage requirements in TSs 1.40, 1.41, 3/4.9.13 and 3/4.9.14, including updates to surveillance requirements for storing fuel assemblies and TS Figures detailing storage patterns and minimum fuel burnup versus fuel enrichment; (2) eliminate the requirement for cell blockers in Region 1 fuel storage racks; (3) modify SFP soluble boron requirements in 3/4.9.1.2; and (4) modify the description of SFP criticality control in TS 5.6.1.1. The Nuclear Regulatory Commission (NRC) staff is reviewing the submittal and has determined that the additional information related to the Boral neutron-absorbing material in the SFP as requested below are needed to complete its review.
RAI-MCCB-1 Part 50.68(b)(4) of Title 10 of the Code of Federal Regulations (10 CFR) states, in part, that the k-effective (keff) of the spent fuel storage racks loaded with fuel of the maximum fuel assembly reactivity must not exceed 0.95. In order to demonstrate that keff doesnt exceed 0.95, the licensee submitted its SFP criticality analysis, for MPS3, as part of its LAR dated May 3, 2018. This analysis, in part, takes credit for the neutron absorbing properties of the Boral material installed in the SFP racks.
In its LAR, the licensee referenced its response to requests for additional information (RAI) letter dated November 22, 2017, related to Generic Letter 2016, Monitoring of Neutron-Absorbing Materials in Spent Fuel Pools (ADAMS Accession No. ML17338A057), to provide information regarding the Boral monitoring program at MPS3. In the RAI response, the licensee noted that it had discovered weight loss with an unknown cause in its Boral coupons since their installation in 2000. In addition, the licensee stated that it did not discover any degradation that would impact SFP criticality. In order to have reasonable assurance that the weight loss has not impacted the SFP criticality, the NRC staff has the following questions:
(a) Has the weight loss caused any dimensional changes (e.g. length, width, or thickness) in the Boral coupons?
(b) Has there been any decrease in Boron 10 (B-10) areal density (AD) in the coupons?
(c) Provide any corrective actions taken to mitigate the degradation of the Boral material, and describe how these actions are meant to mitigate, or account for any impacts to the SFP criticality analysis due to the weight loss of the Boral coupons.
RAI-MCCB-2 10 CFR 50.68(b)(4) states, in part, that the keff of the spent fuel storage racks loaded with fuel of the maximum fuel assembly reactivity must not exceed 0.95. The MPS3 TS 5.6.1.1, Fuel Storage - Criticality, ensures the sub-criticality requirements of 10 CFR 50.68(b)(4) are met. The keff found in the SFP criticality analysis is used to demonstrate compliance with TS 5.6.1.1. Certain assumptions in the SFP criticality analysis rely on the condition of the Boral neutron-absorbing material. In order to verify the assumed values for certain properties of Boral (Boron-10 areal density, length, width, etc.), the licensee has previously implemented a Boral coupon monitoring program.
Because the Boral coupon monitoring program provides assurance, in part, that TS 5.6.1.1 will continue to be met, the NRC staff requires assurance that the coupon monitoring program will not be subject to changes which reduce the effectiveness of the program. Describe how the Boral coupon monitoring program will be controlled (e.g., UFSAR/TS update) to provide assurance that changes reducing the effectiveness of the program will not be made.