ML22076A018
| ML22076A018 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 03/16/2022 |
| From: | Henderson J Virginia Electric & Power Co (VEPCO) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 22-058 | |
| Download: ML22076A018 (6) | |
Text
VIRGINIA ELECTRJC AND POWER COMPANY RICHMOND, VIRGINIA 23261 MAR 1 6 2022 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNITS 1 AND 2 ANNUAL CHANGES, TESTS, AND EXPERIMENTS REPORT REGULATORY COMMITMENT EVALUATION REPORT Serial No.22-058 SPS/MMT RO Docket Nos.
50-280 50-281 License Nos. DPR-32 DPR-37 Virginia Electric and Power Company hereby submits the annual report of Changes, Tests, and Experiments pursuant to 10 CFR 50.59(d)(2) implemented at Surry Power Station. The Attachment provides the descriptions and summaries of the Regulatory Evaluations and the Regulatory Commitment Change Evaluation completed in 2021. There were no Regulatory Commitment Change Evaluations completed in 2021.
Should you have any questions regarding this report, please contact Michael M. True, Jr. at (757) 365-2446.
Very truly yours, ~
Jo nny CJerson Director Nuclear Safety & Licensing Surry Power Station Attachment Commitments made in this letter: None cc:
United States Nuclear Regulatory Commission, Region II Marquis One Tower, Suite 1200 245 Peachtree Center Avenue, NE Atlanta, Georgia 30303-1257 NRC Senior Resident Inspector Surry Power Station
Attachment Surry Units 1 & 2 Serial No.22-058 10 CFR 50.59 Annual Report Page 2 of 6 10 CFR 50.59 Changes, Tests, and Experiments, and Regulatory Commitment Evaluations for 2021 SU-20-00118/Rev. 0 Regulatory Evaluation 07/30/2021
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Description:==
The proposed activity removes the pressurizer cubicle roof blocks (Elevation 67'-6") from the Unit 2 containment structure. The roof blocks were designed and installed to act as a missile barrier to protect the containment liner from internally generated missiles originating from the pressurizer cubicle. The Design Engineering Change Package (DECP), SU 00118, evaluates the notable high-energy component missile sources within the pressurizer cubicle and has determined that all of the sources are not credible to generate missiles; therefore, the pressurizer cubicle roof blocks are not required to function as a missile barrier.
With the pressurizer cubicle roof blocks removed, the pressurizer cubicle temperature is expected to decrease due to natural circulation with the containment air. The maximum temperature change the pressurizer cubicle could theoretically experience would be the delta temperature between the pressurizer cubicle and the containment temperature (~30° F). However, based on the heat input of the pressurizer within the cubicle, a 30° F change is not likely. The DECP and ETE-SU-2021-0004 "Pressurizer Safety Valve Lift Pressure Due to Temperature Change" has evaluated the expected temperature change and any potential impact on the PORV's, PSVs, and all other components within the cubicle and has determined that there is negligible impact and the change will not result in any of the components operating outside of their design limits.
Summary:
The proposed activity removes the pressurizer cubicle roof blocks (Elevation 67'-6") in the Unit 2 Containment structure. The roof blocks were designed and installed to act as a missile barrier to protect the containment liner from internally generated missiles originating from the Pressurizer Cubicle. The DECP, SU-20-00118, evaluates all of the potential missile sources within the pressurizer cubicle and has determined that the industry experience concerning bolted fasteners demonstrates that failure modes do not result in missile generation. Additionally, the station safeguards ensure that degraded Reactor Coolant system pressure boundary components are identified quickly and properly addresses long before progressive failure could occur. As a result, components within the pressurizer cubicle are not creditable missile sources; therefore, the Pressurizer cubicle roof blocks are not required to function as a missile barrier.
The activity of permanently removing the pressurizer roof blocks provides benefits to the station.
Serial No.22-058 10 CFR 50.59 Annual Report Page 3 of 6 Heavy load lift reduction: The removal of the pressurizer missile shield roof reduces the risk of heavy load lifting and movement. The pressurizer missile shield roof blocks are removed each refueling outage and during forced outages. The risk associated with this lifting and movement will be eliminated.
Reduction in ambient temperature: The removal of the pressurizer missile shield roof will reduce the ambient temperature in the pressurizer cubicle. This will reduce component thermal aging effects.
Facilitates inspection: The removal of the pressurizer missile shield roof will aid inspection of component located on top of the pressurizer. Bolted connections can be inspected at hot shutdown conditions with the RCS at operating pressure. Should a leak be present, this should help aid in its identification.
Outage dose savings: The removal of the pressurizer missile shield roof will reduce man-rem exposure.
A 10CFR50.59 Screen was performed which determined that, the permanent removal of the pressurizer cubicle roof blocks will adversely affect the design function of the containment liner. The containment liner is a "Defense-in-Depth 11 barrier which is protected extensively through the usage of engineered features such as the usage of missile barriers to prevent internally generated missiles from striking the containment liner. Although the DECP has determined that the high-energy components within the pressurizer cubicle are not credible at generating missiles, the removal of the missile barrier safety feature is adverse and requires a 1 0CFR50.59 Evaluation. Both the creditability for missile generation and the removal of the missile barrier are considered linked changes when evaluated against the effects on the containment liner's design functions. The design functions are described below:
UFSAR Section 15.5.1.11 describes pipe ruptures in pressure piping and equipment producing missiles that are shielded from striking the containment liner using reinforced concrete walls and floors.
UFSAR Section 15.5.1.8 describes the steel liner of the containment structure being designed to function as a gastight membrane and being protected from potential interior missiles by interior concrete shield walls. The steel liner is designed to withstand the effects of all temperature, earthquake, and pressure loads, including the effect of the sub-atmospheric operating pressure.
The creditability for missile generation and the removal of the pressurizer cubicle roof blocks missile barrier were evaluated against the effects on the containment liner's design function using the eight (8)10CFR50.59 questions. The evaluation concluded that the activity does not result in more than a minimal increase in the frequency and consequences of an accident, and the likelihood of occurrence and consequences of a malfunction of an SSC important to safety, as previously evaluated in the SAR (i.e., Part II, Questions, 1-4); does not create the possibility for an accident or malfunction to an SSC important to safety of a
Serial No.22-058 10 CFR 50.59 Annual Report Page 4 of 6 different type than any previously evaluated in the SAR (i.e., Part 11, Questions 5-6); result in a design basis limit for a fission product barrier as described in the SAR being exceeded or altered (i.e., Part II, Question 7) nor result in departure from a method of evaluation described in the SAR used in establishing the design bases or in the safety analyses (i.e.,
Part 11, Question 8), The activity can be implemented without prior NRG approval.
Serial No.22-058 10 CFR 50.59 Annual Report Page 5 of 6 ETE-NAF-2020-0105, Rev. 0 Regulatory Evaluation 07/29/2021
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Description:==
The activity being reviewed is the implementation of topical report PWROG-17034-P-A into UFSAR Section 5.4.1.3, "Long Term LOCA Mass and Energy Release Analysis" as described in ETE-NAF-2020-0105, Revision 0. PWROG-17034-P-A confirms the continued applicability of the WCAP-10325-P-A methodology despite the issue identified in lnfoGram 14-1 of the material properties associated with the stainless steel thermal conductors. The activity involves an update to the Surry Units 1 and 2 UFSAR to include PWROG-17034-P-A as a reference in Sections 5.4.1.3.1 and 5.4 (References).
Summary:
The activity is the implementation of topical report PWROG-17034-P-A which supplements the LOCA mass and energy release methodology documented in WCAP-10325-P-A. The activity is limited to the change in method of evaluation for the generation of mass and energy releases to containment following a LOCA and support UFSAR Section 5.4.
PWROG-17034-P-A was approved by the NRC with two Conditions and Limitations. The first restriction is to ensure NSAL-06-6, NSAL-11-5 and NSAL-14-2 have been addressed.
The second condition limits the approval to large dry and/or sub-atmospheric containment designs. Both of these Conditions and Limitations are met for Surry Units 1 and 2. The activity does not result in a departure from a method of evaluation described in the SAR Therefore, the 10 CFR 50.59 evaluation concluded that prior NRC approval is not required for this activity.
ETE-SU-2021-0037/Rev. 0 Regulatory Evaluation
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Description:==
Serial No.22-058 10 CFR 50.59 Annual Report Page 6 of 6 12/14/2021 ETE-SU-2021-0037 provides the technical basis for alternate methodology in accordance with NEI 08-05 and RIS 2008-28 for the NUREG-0612 heavy load lifts of the Emergency Service Water Pumps and associated components (diesel, right angle gear drive, and diesel pedestal) to address NUREG-0612 heavy loads conducted during power operation or shutdown conditions as a configuration management activity with administrative controls established in accordance with 10 CFR 50.65(a)(4).
Summary:
The activity proposed in ETE-SU-2021-0037 revises the Surry Power Station heavy loads program to incorporate the guidelines of NEI 08-05 into the station's licensing basis for the Emergency Service Water Pumps and associated components (diesel, right angle gear drive, and diesel pedestal). These guidelines establish a revised licensing basis for the handling heavy loads associated with the Emergency Service Water Pumps and associated equipment that are considered methods approved by the NRC for the specified applications consistent with the provisions of 10 CFR 50.59.