ML22115A104

License Amendment Request- Technical Specifications Nozzle Blockage Testing Requirement Change for Reactors Building Spray System

ML22115A104
Person / Time
Site:	Summer
Issue date:	04/22/2022
From:	Lawrence D Dominion Energy South Carolina
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
22-034
Download: ML22115A104 (26)

Text

Dominion Energy South Carolina, Inc.

5000 Dominion Boulevard, Glen Allen, VA 23060 DominionEnergy.com Attn: Document Control Desk April 22, 2022 U. S. Nuclear Regulatory Commission Washington, DC 20555-0001 DOMINION ENERGY SOUTH CAROLINA VIRGIL C. SUMMER NUCLEAR STATION UNIT 1

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Serial No.:

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Docket No.:

License No.:

22-034 RO 50-395 NPF-12 LICENSE AMENDMENT REQUEST -

TECHNICAL SPECIFICATIONS NOZZLE BLOCKAGE TESTING REQUIREMENT CHANGE FOR REACTOR BUILDING SPRAY SYSTEM Pursuant to the provisions of 10 CFR 50.90, Dominion Energy South Carolina, Inc.

(DESC), hereby submits a License Amendment Request (LAR) for the Virgil C. Summer Nuclear Station (VCSNS) Unit 1.

The proposed amendment would modify the VCSNS Technical Specifications (TS) for the Reactor Building (RB) Spray System.

TS surveillance requirement (SR) 4.6.2.1.d currently requires performing an air or smoke test through each spray header and verifying each spray nozzle is unobstructed at least once every ten years.

DESC proposes to replace the fixed ten-year interval with a requirement to verify the spray nozzles are unobstructed following activities that could cause nozzle blockage.

Additionally, the specific details limiting the testing method to an air or smoke test will be removed. VCSNS will add applicable spray nozzle testing information in the TS Bases for SR 4.6.2.1 upon implementation of the proposed change including information that prompts performance of an evaluation to determine the appropriate test method if it is determined that performance of the surveillance is required. Examples of possible test methods will also be included in the TS Bases.

A detailed description of the proposed change, including technical justification, is provided in Attachment 1 to this letter. provides the existing TS pages marked-up to show the proposed changes. provides the revised (clean) TS pages. - provides the proposed TS Bases changes (for information only). provides the no significant hazards consideration determination.

DESC requests NRC review and approval of the proposed license amendment by April 6, 2023, to support planning for the Spring 2023 refueling outage (RF-27) with a 60-day implementation period. There are no commitments made in this request.

In accordance with 10 CFR 50.91, a copy of this application, with attachments, is being provided to the designated South Carolina State Official.

Serial No.22-034 Docket No. 50-395 Page 2 of 3 Should you have any questions regarding this submittal, please contact Yan Gao at (804) 273-2768.

Douglas C awrence Vice President - Nuclear Engineering and Fleet Support COMMONWEAL TH OF VIRGINIA COUNTY OF HENRICO The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by Douglas C. Lawrence, who is Vice President - Nuclear Engineering and Fleet Support of Dominion Energy South Carolina, Inc. He has affirmed before me that he is duly authorized to execute and file the foregoing document on 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 21-,JP day of Apr; I

, 2022.

My Commission Expires: i-zb1kif Attachments:

CRAIG D SLY Notary Public Commonwealth of Virginia Reg.# 7518653

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My Commission Expires December 31, 26"_

1. Description and Technical Justification

2. Proposed TS Changes

3. Revised TS (clean) Pages

4. Proposed TS Bases Changes

5. No Significant Hazards Consideration Determination

cc:

U.S. Nuclear Regulatory Commission, Region II Marquis One Tower 245 Peachtree Center Avenue, NE Suite 1200 Atlanta, Georgia 30303-1257 Mr. G. Edward Miller NRC Senior Project Manager U.S. Nuclear Regulatory Commission One White Flint North Mail Stop 09 E-3 11555 Rockville Pike Rockville, Maryland 20852-2738 NRC Senior Resident Inspector V.C. Summer Nuclear Station Ms. Anuradha Nair-Gimmi Bureau of Environmental Health Services Serial No.22-034 Docket No. 50-395 Page 3 of 3 South Carolina Department of Health and Environmental Control 2600 Bull Street Columbia, SC 29201 Mr. G. J. Lindamood Santee Cooper - Nuclear Coordinator 1 Riverwood Drive Moncks Corner, SC 29461 DESCRIPTION AND TECHNICAL JUSTIFICATION Virgil C. Summer Nuclear Station (VCSNS) Unit 1 Dominion Energy South Carolina, Inc. (DESC)

Serial No.22-034 Docket No. 50-395

TABLE OF CONTENTS Serial No.22-034 Docket No. 50-395 : Page 1 of 12 1.0

SUMMARY

DESCRIPTION............................................................................................. 2 2.0 DETAILED DESCRIPTION.............................................................................................. 2 2.1 System Design and Operation..................................................................................... 2 2.2 Current Requirement................................................................................................... 3 2.3 Reason for the Proposed Change................................................................................ 3 2.4 Description of the Proposed Change............................................................................ 3

3.0 TECHNICAL EVALUATION

............................................................................................. 4 3.1 Technical Analysis....................................................................................................... 4 3.1.1.

Performance History................................................................................................. 4 3.1.2.

Nozzle Blockage Mechanisms.................................................................................. 5 3.1.3.

Foreign Material Exclusion (FME)............................................................................. 6 3.1.4.

Method of Surveillance............................................................................................. 7 3.2 Conclusions................................................................................................................. 7

4.0 REGULATORY EVALUATION

........................................................................................ 7 4.1 Applicable Regulatory Requirements/Criteria............................................................... 7 4.2 Comparison to NUREG-1431 Revision 5 Requirements.............................................. 9 4.3 Precedent................................................................................................................... 10 4.4 No Significant Hazards Consideration Determination.................................................. 10

5.0 ENVIRONMENTAL CONSIDERATION

.......................................................................... 10

6.0 REFERENCES

............................................................................................................... 11

Serial No.22-034 Docket No. 50-395 : Page 2 of 12 Description and Technical Justification 1.0

SUMMARY

DESCRIPTION The proposed amendment request changes Virgil C. Summer Nuclear Station (VCSNS),

Unit 1, Technical Specifications (TS) surveillance requirement (SR) 4.6.2.1.d for the Reactor Building (RB) Spray System.

Currently, VCSNS TS SR 4.6.2.1.d requires performing an air or smoke test through each containment spray header and verifying each spray nozzle is unobstructed at least once per ten years. Dominion Energy South Carolina (DESC) proposes to replace the current TS SR 4.6.2.1.d with a new requirement to verify that each spray nozzle is unobstructed following activities that could cause nozzle blockage. Additionally, the specific details in TS SR 4.6.2.1.d limiting the test method to an air or smoke or equivalent flow test will be removed. VCSNS will revise the TS Bases for SR 4.6.2.1 upon implementation of the proposed change to add applicable spray nozzle testing information and information that prompts performance of an evaluation to determine the appropriate test method if it is determined that performance of the surveillance is required. Examples of possible test methods will also be included in the TS Bases, and include, but not limited to, visual inspection, air or smoke or equivalent flow test, and draining and flushing the filled portions of the system inside containment.

2.0 DETAILED DESCRIPTION 2.1 System Design and Operation The VCSNS RB spray system includes a total of 330 spray nozzles. These nozzles are ramp type, hollow cone nozzles.

The spray nozzles are located on 6 rings.

The arrangement of the spray rings within the RB is such that essentially all of the free volume above the operating floor, elevation 463', is exposed to the spray. Below the operating floor elevation, areas outside the secondary shield walls are shielded from the spray.

However, the atmosphere in these areas is mixed with the rest of the volume inside the secondary shield walls. The volume inside the secondary shield walls, with the exception of the pressurizer compartment, is open to the spray. ( (6.1 ], Section 6.2.3.2.1)

During normal plant operation, the RB spray system is in standby condition with spray pump suction aligned to receive water from the Refueling Water Storage Tank (RWST).

Operation of the system is initiated automatically following a Loss of Coolant Accident (LOCA) or Main Steam Line Break (MSLB) by signals from the Engineered Safety Features (ESF) Actuation System when Reactor Building pressure increases to the actuation setpoint. The RB spray system can also be started manually from the control room.

During the injection phase following a LOCA, the spray pumps receive fluid from the RWST and sodium hydroxide storage tank. The solutions are carried through the spray pump discharge lines to the spray headers and are then sprayed into the Reactor Building

Serial No.22-034 Docket No. 50-395 : Page 3 of 12 atmosphere through the spray nozzles. The spray is collected in the bottom of the RB with water from the Emergency Core Cooling System (ECCS) and the Reactor Coolant System (RCS) in the RB recirculation sumps. During the recirculation phase, the spray pumps may take suction from the sumps in the RB.

The spray droplets absorb heat as they fall through the steam-air atmosphere in the RB, thereby reducing RB atmosphere temperature ([6.1 ], Section 6.2.2.2.1.2). Additionally, the spray is credited for iodine removal following a design basis accident to reduce post-accident dose consequences.

Debris which washes down to the sumps and passes through the sump strainer has been evaluated for the potential to block and erode downstream systems and components.

The size of the debris is limited by the 1 /16-inch round holes in the perforated plate strainer ([6.1], Se_ction 6.2.2.2.1). The inner diameter of the spray nozzles is 3/8 inch.

2.2 Current Requirement TS 4.6.2, "Depressurization and Cooling Systems," currently states in part:

4.6.2.1 Each reactor building spray system shall be demonstrated OPERABLE:

d. At least once per 10 years by performing an air or smoke or equivalent flow test through each spray header and verifying each spray nozzle is unobstructed.

2.3 Reason for the Proposed Change The proposed change will eliminate unnecessary testing of the spray nozzles by only requiring verification that each nozzle is unobstructed following activities or conditions that could potentially cause nozzle blockage. The current surveillance requires workers to verify air flow at each nozzle. The nozzles are located at high elevations inside the Reactor Building and in a potentially elevated temperature environment. Limiting the exposure to such conditions will reduce the risk to personnel safety.

VCSNS has determined that the proposed change more accurately reflects situations where spray nozzle testing should be performed to verify system operability.

2.4 Description of the Proposed Change DESC proposes that VCSNS TS SR 4.6.2.1.d be revised to state:

d. By verifying each spray nozzle is unobstructed following activities that could cause nozzle blockage.

The proposed change will replace the current 10-year flow test frequency with a surveillance frequency based on the occurrence of activities or conditions that could potentially cause nozzle blockage. Additionally, the specific details limiting acceptable

Serial No.22-034 Docket No. 50-395 : Page 4 of 12 test methods to an air, smoke or equivalent flow test will be removed from TS 4.6.2.1.

The associated TS Bases section will be updated with applicable spray nozzle testing information and will provide information related to performance of an evaluation to determine the appropriate test method if it is determined that performance of the surveillance is required. Examples of acceptable test methods will also be provided in the TS Bases, including, but not limited to, visual inspection, air or smoke or equivalent flow test, and draining and flushing the filled portions of the system inside containment.

3.0 TECHNICAL EVALUATION

3.1 Technical Analysis The proposed amendment will modify VCSNS TS SR 4.6.2.1.d to eliminate the 10-year frequency for verifying Reactor Building spray nozzles are unobstructed and to remove the testing methodology details prescribed by the surveillance. Currently, the surveillance requires the spray nozzles be tested at least once per 10 years by performing an air or smoke or equivalent flow test through each spray header and verifying each spray nozzle is unobstructed.

Generic Letter 93-05 [6.4), "Line-Item Technical Specifications Improvements to Reduce Surveillance Requirements for Testing During Power Operation," was used as the basis for the current 10-year surveillance frequency due to the stainless-steel construction of the nozzles and piping. No coating material is used in the Reactor Building spray piping or nozzles at VCSNS, thus eliminating the potential for clogging of the spray nozzles with such material. DESC proposes to replace the current 10-year frequency with a statement that would require verification that each spray nozzle is unobstructed following "activities that could cause nozzle blockage."

Since maintenance directly or indirectly involving the Reactor Building spray system is infrequent, the proposed surveillance will ensure the spray nozzles remain unobstructed following activities that could potentially cause nozzle blockage testing is performed.

3.1.1. Performance History Prior to initial plant startup, flow tests were performed to verify that the various orifices were properly sized to provide the correct mixture of sodium hydroxide solution and RWST water during operation of the RB spray system. ([6.1 ], Section 6.2.2.4.1)

Periodic in-place air flow tests through the spray nozzles have been conducted in accordance with the interval specified in the TS.

Spray nozzles were verified unobstructed by injecting low pressure air or smoke into the lines to the spray headers through air test connections. The spray isolation valves were closed during these tests.

Visual observation of the smoke or of telltales (such as balloons or tufts), served as verification that the nozzles were not restricted. ([6.1], Section 6.2.2.4.1.2)

VCSNS has performed the following air flow tests in accordance with the current TS SR 4.6.2.1.d requirement:

No.

Date 1

3/29/1987 2

10/22/1991 3

4/30/2002 4

11/1/2012 Serial No.22-034 Docket No. 50-395 : Page 5 of 12 Refueling Outage No.

3 6

13 20 The results of each test demonstrated unobstructed flow through each spray nozzle.

3.1.2. Nozzle Blockage Mechanisms NUREG-1366

[6.5],

"Improvements to Technical Specifications Surveillance Requirements," reported the results of an NRG staff review of industry experience related to problems with RB spray systems. The report found that, in general, once the systems are tested after construction, they are not subject to blockage. The problems regarding nozzle blockage identified in the report were related to construction activities.

One postulated mechanism for blockage of spray nozzles is corrosion products.

However, the containment spray headers and nozzles are fabricated of Austenitic stainless steel and are located in a dry environment. Therefore, blockage of the spray nozzles from corrosion products is unlikely.

Another potential mechanism for nozzle blockage is accumulation of solid boric acid in the spray lines or nozzles due to evaporated borated water. The spray headers are normally maintained dry and isolated from water by normally closed containment isolation valves that are subject to 10 CFR 50, Appendix J, Type C leakage testing.

During refueling outages, the spray ring manual isolation valves are locked closed to ensure that inadvertent spray actuation cannot take place. As a further means to prevent materials from entering the system during refueling outages, the containment sumps have covers installed. Consequently, blockage of the spray nozzles from solid boric acid accumulation or foreign material is unlikely. However, should there be inadvertent fluid flow though the nozzles, (e.g., the result of spurious actuation), DESC would evaluate the need for testing and determine the appropriate testing method for verifying the nozzles are unobstructed.

As previously stated, NUREG-1366 [6.5], "Improvements to Technical Specifications Surveillance Requirements," reported the results of an NRG staff review of industry experience related to problems with RB spray systems. The report summarizes the problems identified with PWR containment spray systems that were discovered by means of an air or smoke test. Three cases were identified, and all three cases involved a construction error. This report was published in December of 1992. A search of the Licensee Event Report (LER) Database was performed for LERs containing the word "spray nozzle" in the title and with submittal dates after December 1, 1992. Two relevant LERs ([6.14], [6.15]), were identified regarding spray nozzle blockage; both from the same unit. Both LERs describe spray nozzle obstructions caused by boric acid solution which was not removed from system low points that entrapped water in the spray headers after the headers were filled with borated water during previous spray header overfill events.

The entrapped borated water subsequently evaporated, causing boric acid to precipitate and form obstructions in the nozzles. The number of blocked nozzles was low. The first

Serial No.22-034 Docket No. 50-395 : Page 6 of 12 event resulted in two blocked nozzles out of 620. The second event resulted in 7 blocked nozzles. The LERs indicate that even if the boric acid deposits were not displaced or dissolved by containment spray header water pressure and the nozzles remained obstructed, the remaining 618 spray nozzles that were not obstructed in the spray system would have provided the required spray flow. To ensure VCSNS is not susceptible to this potential failure mode, the proposed changes to the VCSNS TS Bases will require an evaluation be performed to determine if a surveillance needs to be performed given an event, such as a spray header overfill event, and the appropriate test method of the surveillance if it is determined that performance of the surveillance is required.

3.1.3. Foreign Material Exclusion (FME)

The FME program at VCSNS is governed by a nuclear fleet procedure. The FME fleet procedure specifies appropriate precautions to minimize inadvertent and uncontrolled introduction of foreign materials into plant systems and components. The FME procedure requires that personnel perform and document an "as found" inspection when a system, component, or process is opened or breached.

The procedure also includes FME practices for maintaining cleanliness of plant systems and components during maintenance activities that create debris, such as welding and grinding. Final cleanliness inspections verify the system, component, or process is free of foreign material prior to final closure. The VCSNS corrective action program is used in the event of a loss of FME integrity. If FME integrity is lost through the intrusion or discovery of foreign material, the FME procedure directs the worker to stop work, notify the First Line Supervisor, and develop a recovery plan for the foreign material. The recovery plan includes an event description, cause of event, consequences of the event, retrieval plan, and retrieval results. If the retrieval of the foreign material is unsuccessful, an engineering evaluation is required to determine further necessary actions.

DESC performed a review of maintenance activities performed on the RB spray system since the last containment spray nozzle test during Refueling Outage 20 in November of 2012. The review identified one issue involving foreign material exclusion (FME) that impacted the RB spray system. During RF26 in 2021, a 6-inch adjustable wrench was dropped through the 'B' RHR sump grating from the RB 412 elevation (ground level) while gathering tools following a tagout. The wrench was leaning against the outer FME screen in the back corner of the 'B' RHR sump. This issue was documented in the corrective action program and the dropped object was successfully retrieved. This wrench was not located inside the Reactor Building Spray piping that is tested via the VCSNS procedure.

During other maintenance activities on the RB spray system since the last RB spray nozzles test, work practices and post work inspections have maintained system cleanliness. There haye been no work activities on any of the RB spray nozzles or headers since the last RB spray nozzle test.

The fleet FME procedure provides controls that minimize the potential for introducing foreign material into systems during maintenance activities, and these controls would be in place if the RB spray system is open for maintenance. Therefore, the FME program

Serial No.22-034 Docket No. 50-395 : Page 7 of 12 provides reasonable assurance that foreign material that could adversely affect the RB spray system's ability to perform its safety function would not be left in the system as a result of maintenance activities.

3.1.4. Method of Surveillance As discussed in NUREG-1366 [6.5), "Improvements to Technical Specifications Surveillance Requirements," the performance of an air or smoke test provides qualitative insights on RB spray nozzle condition, in terms of blockage. The performance of an appropriate test method identified via an evaluation as indicated in the proposed TS Bases, such as visual inspection would similarly provide a qualitative methodology to satisfy the surveillance requirement and verify that the nozzles are unobstructed.

Draining/flushing of the affected portions of the system would be adequate to confirm that the spray nozzles are unobstructed since water flow would be required to transport any debris in the RB spray piping to the spray nozzles.

3.2 Conclusions NUREG-1366 [6.5), found that cases of spray nozzle obstruction in pressurized water reactor RB spray systems were related to construction activities. Previously performed surveillance tests at VCSNS found that the spray nozzles were unobstructed. Therefore, the proposed changes, along with existing programs, processes, and procedures at VCSNS will ensure the RB spray nozzles remain unobstructed, and that appropriate tests will be performed should activities or conditions occur which could potentially cause spray nozzle obstruction. A review of LERs submitted after December 1, 1992, shows that the proposed changes would not result in VCSNS being susceptible to the same nozzle blockage causes described in these LERs. The design of the RB spray system, its maintenance and testing history, FME program controls, and the proposed changes to adopt an event-based testing approach specified in TS SR 4.6.2.1.d for verifying no nozzle blockage provide reasonable assurance that the RB spray system nozzles will remain unobstructed.

4.0 REGULA TORY EVALUATION 4.1 Applicable Regulatory Requirements/Criteria The proposed change has been evaluated to determine whether applicable regulations and requirements continue to be met. The following applicable regulations and regulatory requirements were reviewed in making this determination:

10 CFR 50.36 The regulations at Title 10 of the Code of Federal Regulations (10 CFR) Section 50.36(c)(3) states:

Serial No.22-034 Docket No. 50-395 : Page 8 of 12 "SuNeillance requirements. SuNeillance requirements are requirements relating to test, calibration, or inspection to assure that the necessary quality of systems and components is maintained, that facility operation will be within safety limits, and that the limiting conditions for operation will be met.

11 The regulatory requirements in 10 CFR 50.36 are not specific regarding surveillance requirements other than to assure that the necessary quality of systems and components is maintained that facility operation will be within safety limits, and that the limiting conditions for operation will be met.

The proposed change is consistent with the requirements of 10 CFR 50.36(c)(3).

The construction permit for VCSNS Unit 1 was issued by the Atomic Energy Commission (AEC) on March 21, 1973. The Operating License was issued on August 6, 1982.

NUREG 0717 [6.6], "Safety Evaluation Report related to the operation of Virgil C. Summer Nuclear Station," discusses VCSNS conformance with the General Design Criteria. In a letter [6.20] dated November 14, 1980, VCSNS addressed compliance with 10 CFR Parts 20, 50, and 100 including the General Design Criteria. The NRG evaluated the final design and the design criteria and concluded, subject to the applicant's adoption of the additional requirements imposed by the NRG as discussed in the Safety Evaluation Report [6.6], that the facility had been designed to meet the requirements of the General Design Criteria. In the November 14, 1980, letter [6.20], VCSNS provided a discussion to compare the plant design with the General Design Criteria (GDC) as they appeared in 10 CFR 50 Appendix A. It was this discussion, including the identified exceptions, which formed the original plant licensing basis for compliance with the GDC. This discussion is contained in the VCSNS Updated Final Safety Analysis Report (UFSAR) [6.1 ], Section 3.0, "Design of Structures, Components, Equipment and Systems," with more details provided in other UFSAR [6.1] sections. Changes have been made to the original UFSAR

[6.1] GDC discussions to reflect commitments and changes made to the facility over the life of the plant. Therefore, the GDC discussions in the UFSAR [6.1] constitute the VCSNS Unit 1 licensing bases with respect to compliance with the GDC. These design criteria are referenced in Chapter 3 of the VCSNS UFSAR [6.1]. GDC Criteria 38, 39 and 40 state:

General Design Criterion 38 General Design Criterion 38 - Containment heat removal. A system to remove heat from the reactor containment shall be provided. The system safety function shall be to reduce rapidly, consistent with the functioning of other associated systems, the containment pressure and temperature following any loss-of-coolant accident and maintain them at acceptably low levels.

General Design Criterion 39 Criterion 39 - Inspection of containment heat removal system. The containment heat removal system shall be designed to permit appropriate periodic inspection of important components, such as the torus, sumps, spray nozzles, and piping to assure the integrity and capability of the system.

General Design Criterion 40 Serial No.22-034 Docket No. 50-395 : Page 9 of 12 Criterion 40 - Testing of containment heat removal system.

The containment heat removal system shall be designed to permit appropriate periodic pressure and functional testing to assure (1) the structural and leak tight integrity of its components, (2) the operability and performance of the active components of the system, and (3) the operability of the system as a whole, and under conditions as close to the design as practical the performance of the full operational sequence that brings the system into operation, including operation of applicable portions of the protection system, the transfer between normal and emergency power sources, and the operation of the associated cooling water system.

The proposed change has no effect on the design of the containment heat removal system. The applicable GDC do not specify the frequency or method of inspection. The discussions in the UFSAR [6.1) regarding Criterion 39 currently state that functional operability of each nozzle is verified by an air or smoke test. This discussion in the UFSAR [6.1] will be updated to allow for other surveillance methods pending NRC approval of this request.

The changes proposed in this request will continue to meet the above regulatory requirements.

4.2 Comparison to NUREG-1431 Revision 5 Requirements VCSNS has not adopted the Improved Standard Technical Specifications of NUREG-1431 [6.3] and is still based on the Standard Technical Specifications described in NUREG-0452 [6.2].

VCSNS TS SR 4.6.2.1.d is comparable to SR 3.6.6.A/B.9 of NUREG-1431 [6.3), which states: "verify each spray nozzle is unobstructed."

The frequency specified in NUREG-1431 [6.3) is at the first refueling, and every 10 years (or in accordance with the Surveillance Frequency Control Program). The proposed change to remove the method of surveillance (i.e., air or smoke or equivalent flow test) from VCSNS SR 4.6.2.1.d is consistent with SR 3.6.6.A/B.9 in NUREG-1431 [6.3).

The method of performing the verification is not included in the NUREG-1431 [6.3) SR, but the bases for NUREG-1431 [6.3] SR 3.6.6.A/B.9, discusses that, with the containment spray inlet valves closed and the spray header drained of any solution, low pressure air or smoke can be blown through test connections to verify each spray nozzle is unobstructed.

VCSNS will revise the Bases for VCSNS TS SR 4.6.2.1 upon implementation of the proposed change to require an evaluation to determine the appropriate test method if it is determined that performance of the surveillance is required.

Examples of possible test methods will also be provided, including, but not limited to, visual inspection, air or smoke or equivalent flow test, and draining and flushing the filled portions of the system inside containment. This deviates from the NUREG-1431 [6.3]

bases but is consistent with previously approved license amendment requests as discussed in Section 4.3 of this submittal.

4.3 Precedent Serial No.22-034 Docket No. 50-395 : Page 10 of 12 Similar license amendment requests have been reviewed and listed below:

Shearon Harris Nuclear Power Plant, Unit 1, March 24, 2021, [6.13]

Seabrook Station Unit 1, January 30, 2012, [6.7]

Donald C. Cook Units 1 and 2, June 1, 2011, [6.8]

Catawba, McGuire, and Oconee Stations, August 24, 2010, [6.9]

Prairie Island Nuclear Generating Plant, Units 1 and 2, November 6, 2008, [6.1 O], (also included a proposed TS Bases change to include visual inspection and draining/flushing the system as a method of surveillance)

Millstone Power Station, Unit 2, March 31, 2008, [6.11 ], (also included a proposed TS bases change to include visual inspection as a method of surveillance)

Arkansas Nuclear One, Unit 1, July 9, 2008, [6.12], (also included a proposed TS bases change to include visual inspection and draining/flushing the system as a method of surveillance)

Millstone Power Station, Unit 3, May 31, 2005, [6.16]

Millstone Power Station, Unit 2, March 28, 2007, [6.17]

North Anna Power Station, Units 1 & 2, February 26, 2002, [6.18]

Surry Power Station, Units 1 & 2, May 14, 2002, [6.19]

4.4 No Significant Hazards Consideration Determination DESC has evaluated the proposed amendment against the criteria in 10 CFR 50.92 and has determined that operation of VCSNS in accordance with the proposed amendment presents no significant hazards. The DESC evaluation against each of the criteria in 10 CFR 50.92 is provided as Attachment 5 to this amendment request.

5.0 ENVIRONMENTAL CONSIDERATION

DESC has determined that the proposed amendment would revise a requirement with respect to installation or use of a facility or component located within the restricted area, as defined in 10 CFR 20, or would change an inspection or surveillance requirement.

However, the proposed amendment does not involve (i) a significant hazards consideration, (ii) a significant change in the types or a significant increase in the amounts of any effluents that may be released offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure.

Accordingly, the proposed amendment meets the eligibility criterion for a categorical exclusion as set forth in 10 CFR 51.22(c)(9).

Serial No.22-034 Docket No. 50-395 : Page 11 of 12 Therefore, DESC concludes that pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need to be prepared in connection with the proposed amendment.

6.0 REFERENCES

6.1 VCSNS Updated Final Safety Analysis Report (UFSAR) 6.2 NUREG-0452, "Standard Technical Specifications for Westinghouse Pressurized Water Reactors," Rev. 4 6.3 NUREG-1431, "Standard Technical Specifications -

Westinghouse Plants,"

Revision 5 6.4 GL-93-05, "Line-Item Technical Specifications Improvements to Reduce Surveillance Requirements for Testing During Power Operation," September 27, 1993 6.5 NUREG-1366, "Improvements to Technical Specifications Surveillance Requirements," December 1992 6.6 NUREG-0717, "Safety Evaluation Report related to the Operation of Virgil C.

Summer Nuclear Station, Unit No. 1," February 1981 6.7 ADAMS Accession No. ML113260577, NRG letter, "Seabrook Station, Unit No.1-lssuance of Amendment Regarding Containment Spray Nozzles Surveillance Requirement (TAC NO. ME6726)," January 30, 2012 6.8 ADAMS Accession No. ML11112A123, NRG letter, "Donald C. Cook Nuclear Plant, Units 1 And 2 - Issuance of Amendments Re: Containment Spray Nozzle Surveillance Requirement (TAC NOS. ME4125 AND ME4126)," June 01, 2011 6.9 ADAMS Accession ML100690007, NRG letter, "Catawba Nuclear Station, Units 1 and 2, McGuire Nuclear Station, Units 1 and 2, and Oconee Nuclear Station, Units 1, 2, and 3, Issuance of Amendments Regarding Performance Testing of Containment Spray Nozzles (TAC Nos. ME2497, ME 2498, ME2499, ME2500, ME2501, ME2502 and ME2503)," August 24, 2010 6.10 ADAMS Accession No. ML082740226, NRG letter, "Prairie Island Nuclear Generating Plant, Units I and 2 - Issuance of Amendments Re: License Amendment to Revise Containment Spray Nozzle Surveillance Requirements (TAC Nos. MD7362 and MD7363)," November 6, 2008

Serial No.22-034 Docket No. 50-395 : Page 12 of 12 6.11 ADAMS Accession No. ML080720304, NRC letter, "Millstone Power Station, Unit No. 2 - Issuance of Amendment Re: Technical Specification Change Request Regarding Containment Spray Nozzle Test Requirements (TAC NO. MD4992),"

March 31, 2008 6.12 ADAMS Accession No. ML081540218, NRC letter, "Arkansas Nuclear One, Unit 1

- Issuance of Amendment Re: Containment Spray Nozzle Technical Specifications Test Requirements (TAC No. MD831 0)," July 9, 2008 6.13 ADAMS Accession No. ML21083A317, "Shearon Harris Nuclear Power Plant, Unit 1 - License Amendment Request Regarding Change to Containment Spray Nozzle Test Frequency," March 24, 2021 6.14 ADAMS Accession No. ML081120111, Palo Verde 3 - Licensee Event Report 2007-001, Rev. GO-Condition Prohibited by Technical Specification Resulting from Containment Spray Nozzle Blockage, April 7, 2008 6.15 ADAMS Accession No. ML12193A560, Palo Verde 3 - Licensee Event Report 2010-002, Rev. 01 - Condition Prohibited by Technical Specification Resulting from Containment Spray Nozzle Obstruction, June 27, 2012 6.16 ADAMS Accession No. ML042510261, Millstone Power Station, Unit 3, NRC letter, "Issuance of Amendment 222 RE Quench Spray and Recirculation Spray Nozzle Surveillance," May 31, 2005 6.17 ADAMS Accession No. ML070880705, Millstone Power Station, Unit 2, "License Amendment Request re Containment Spray Nozzle Surveillance," March 28, 2007 6.18 ADAMS Accession No. ML020630135, North Anna Power Station Units 1 & 2, "Request for Amendments, Proposed Technical Specification Changes to Revise Quench Spray & Recirculation Spray Nozzles Surveillance Frequency," February 26,2002 6.19 ADAMS Accession No. ML021410334, Surry Power Station, Units 1 &2, "Proposed Technical Specification Change Containment Spray and Recirculation Spray Nozzles Surveillance Frequency," May 14, 2002 6.20 ADMAS Accession No. ML20002A769, Letter South Carolina Electronic & Gas Company to NRC, "Regarding VCSNS Compliance with NRC Regulations,"

November 14, 1980 Proposed TS Changes Virgil C. Summer Nuclear Station (VCSNS) Unit 1 Dominion Energy South Carolina, Inc. (DESC)

Serial No.22-034 Docket No. 50-395

CONJ:6!NdEN! §Y§lEMS 314 8 2 DEPRESSUBIZATION NiP COOLING §YSTEMS WCJQR BVILDJNG SfBAY SVSTEM UKnNG CONOITlON FOR OPEAATION 3.6.2.1 Two lndependen! reac!Of ~

tlfXff'/ IY$ten'IS stlal be OPERABLE wlh each spray system c:apable of taking suclion from tho fNiST and IUIOmallcdy transferring sudiol1 to ti"-'!!

spray sump.

N'Pt.lCABIUJY:

MODES 1. 2, 3. and 4.

~

one reactor ding Sf)r'Y SV$lem ~,.. restore 1ho lnopwabu $flr3Y syum '° OPEJV\\Bl.E 5ta1U$

_. 72 ~

or be ti al least HOT STANDBY 111!\\twn lho llQI 6 hol/1'1; reslore file inoperable spray systein to OF'ERABt.E status lhe ne.kt 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> or be in COLD SHUTDOWN Mthin the fOIOYMg 30 tours.

SURVEIU.ANCE REQUIREIJENTS 4.6.2.1 Each reactor buldilg apniy sY5k,m be dlfmonsh1ed OPERABLE:

a.

At least once per 31 days by;

1. Vetifying that e~ wive (inanu.il, power operated. or autom.itic) kl lh(J flqw 1h that Is not locked. sealed OI' octiefW!s;e MCU!ed i'I posllion Is In Is COITecl pos~. ancl

2. Ve,lfylng ~llt Spray~ susocpiblo to 93S ~

.tre Sl,lffJCll!fllly -

wttn

b.

By verifying, that 11"1 redn:uation flow, each puffll ~

ti dischMge ~e of greater than or equal to 195 J1!iV wtEn JUSUM to ~-4.0_5.

c;,.

At 1ea5t once pet 18 months tllling ~

. by.

1. Ver!Mno that uadi aut

• valve In the flew i,81h aclualaS to a c<<reCl po$l~-cn eadl of Die r~

tt'$1 slgnalt a Phase 'A', Rnctcr-a.dklg

~y Actualio!I, and Coltai,m11,11t 81,np Reciredation.

Serial No.22-034 Docket No. 50-395 : Page 1 of 1 ER

• IT 1 3/46-12 Amendtr\\-oot No. ~

20-i Revised (Clean) TS Pages Virgil C. Summer Nuclear Station (VCSNS) Unit 1 Dominion Energy South Carolina, Inc. (DESC)

Serial No.22-034 Docket No. 50-395

Serial No.22-034 Docket No. 50-395 : Page 1 of 1 CONTAINMENT SYSTEMS 3/4.62 DEPRESSURIZATION AND COOLING SYSTEMS REACTOR BUILDING SPRAY SYSTEM LIMITING CONDITION FOR OPERATION 3.6.21 Two independent reactor buading spray systems shaU be OPERABLE with each spray system capable of taking suction from the RWST and automatically transferring suction to the spray sump.

APPLICABILITY:

MODES 1, 2, 3, and 4.

ACTION:

With one reactor building spray system inoperable, restore the inoperable spray system to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />; restore the inoperable spray system to OPERABLE status within the next 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> or be in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

SURVEILLANCE REQUIREMENTS 4.6.21 Each reactor builomg spray system sha be demonstrated OPERABLE:

a.

At least once per 31 days by:

1. Verifying that each valve (manual, power operated, or automatic) in the flow path that is not locked, sealed or otheiwise secured in position is in its correct position*, and

2. Verifying Containment Spray locanons susceptible to gas accumulation are sufficiently filled with water.

b.

By verifying, that on recirculation flow, each pump develops a discharge pressure of greater than or equal to 195 psig when tested pursuant to Specification 4.0.5.

c.

At least once per 18 months during shutdown, by:

1. Verifying that each automatic valve in the flow path actuates to its correct position on each of the followirtg test signals a Phase 'A', Reactor Building Spray Actuation, and Containment Sump Recirculation.

2. Verifying that each spray pump starts automatically on a Reactor Building Spray Actuation test signal.

d.

By verifying each spray nozzle is unobstructed following activities that could cause nozzle blockage.

• Not required to be met for system vent flow paths opened under administrative control.

SUMMER - UNIT 1 3/4 6-12 Amendment No. 127,2-04 Proposed TS Bases Changes Virgil C. Summer Nuclear Station (VCSNS} Unit 1 Dominion Energy South Carolina, Inc. (DESC}

Serial No.22-034 Docket No. 50-395

CONTAINMENT SYSTEMS BASES REACTOR BUILDING SPRAY SYSTEM (Continued)

Serial No.22-034 Docket No. 50-395 : Page 1 of 2 Containment Spray System w path ping and components have ihe potential IQ deve!Op voids and pockets* or entrained gases. Preventing and managing gas intrusion and accumulation is necessary for proper operation or the containment spray tram and may also prevent a water hammer and pump cav~abon Sclectlon of Conralnment Spray System locabons suscep ble to gas accumulation is based on a review of system design nformation. including ptping and rns~nt drawings. fsometiic drawings, Plan and elevabon drawings, and calculations The des* n review is supplem<!nled by system walkdowns to validate the system high points and to wnfirm the location ~

orientation of important components that can become $0urt:e$ of gas or COUid olllerv.ise cause gas to be lr9pped or difrlcult to remove dllfing system mainlenance or restoration Susoepl1ble loeations depend on pla.n! and sys1em t>>nfigtlration. $ud\\ 8$ $t8ndby VBt$U$ operating condition$_

The Containment Spray System is OPERABLE when ii is sulftcienUy filled wllh Welter. Acceptance crttena are eslablished for the volume of accumulated gas at suscep ble locations_ If accumulated gas h. diSoovered that exceeds ihe acceptance criteria for the suscepbb!e location (Of the ume of aCCtJmulated gas at one or more suscep ble IOC1;1tions ~ceeds an ac:i:eptanc;;e cmeria fOf g.is volume.ii tile i.uction or discharge or a pump), the Surv ance is not met. If it i$ detetmtiled by $UbseQuent evaluation that the CCnlammenl Spray System is not rendered inoperable by the aecumulated gas (i.e., the system is sufficieotly filled with water), the SUrvelllance may be dedared met Accumulated gas should be eltminated or bl'ought within the acceplall(;e criteria llmits.

Containment Spray System locabons susoep le to gas accurnutat10n are monitored and, If gas Is found, the gas volume is compared to the ae:ceptance criteria for the location_ Susceptible locations in the same system flow path which are subject to the same gas intrusion mechanisms may be verified by monitoring a representative sulnel of suscepbble locatiOfls. Monrtoring may not be praclical for localions that are inar.ceSS1b!e due lo radiological or envitonmenlal oondili<>ns. plant oonliguration, or personnel safety. For UleSe locations.

er live methods (e.g.* operating parameters.

remote monrtoring) may be used co monitor the susce.p ble loc.'lhon Monitoring 1$ not required for suscep ib locations \\\\'hen! the maximum potential accumulated gas void vo ume has been eva ated and d ermined lo not challenge system OPERABILITY.

The accuracy of the method used for moni1oong the susceptible locations and trending of lhe results should be sumaenl to assure system OPERABilliY during the Surve lance interval.

The 31 day freqlJency for Survei nee Requirement 4 6.2.1.a 1) takes into conslderaUon the gradual nalvre of gas accumulabon 111 the Containment Spray System piping and the procedural controls governing system operation.

""tn_s_e_rt""'1.-------.

oflltvei~~ Requirement 4.6,2 1.a.1) is modified by a Nate which e,;empts syi;tern vent now palh:; o _

er admini$lralive control The adminl$1rative control should be proceduratized and inckJde deaicaled irnf *dual al lhe system vent palh >Aho is In continuous communication \\-,ith the in the control room The,odivlclual will have a method lo ra

• ly close the system vent r o

• ect.

SUMMER - UNIT 1 B 314 6-3.J Amendment No. 204

Insert 1:

Serial No.22-034 Docket No. 50-395 : Page 2 of 2 Surveillance Requirement 4.6.2.1.d requires verification that each spray nozzle is unobstructed following activities that could cause nozzle blockage. Due to the passive design of the nozzle, confirmation of operability following activities that could result in nozzle blockage is considered adequate to detect obstruction of the nozzles. Normal plant operation and maintenance activities are not expected to trigger performance of this surveillance requirement. However, activities, such as an inadvertent spray actuation that causes fluid flow through the nozzles, a major configuration change, or a loss of foreign material control when working within the respective system boundary, shall be evaluated to determine if surveillance performance is required.

If determined that surveillance performance is required, the evaluation will determine the appropriate method for performing the surveillance. Examples of possible test methods include, but are not limited to, visual inspection, air or smoke or equivalent flow test, and draining and flushing the filled portions of the system inside containment.

Serial No.22-034 Docket No. 50-395 No Significant Hazards Consideration Determination Virgil C. Summer Nuclear Station (VCSNS) Unit 1 Dominion Energy South Carolina, Inc. (DESC)

No Significant Hazards Consideration Determination Serial No.22-034 Docket No. 50-395 : Page 1 of 2 The proposed amendment would change the Virgil C. Summer Nuclear Station (VCSNS),

Unit 1, Technical Specifications (TS) surveillance requirement (SR) for the Reactor Building (RB) Spray System. Currently, VCSNS TS SR 4.6.2.1.d, requires performing an air or smoke or equivalent flow test through each containment spray header and verifying each spray nozzle is unobstructed at least once every ten years. Dominion Energy South Carolina (DESC) proposes to replace the VCSNS TS SR 4.6.2.1.d with a new requirement to verify each spray nozzle is unobstructed following activities that could cause nozzle blockage. Additionally, the specific details limiting the testing method to an air or smoke test will be removed. VCSNS will revise applicable spray nozzle testing information in the TS Bases for SR 4.6.2.1 upon implementation of the proposed change and will instruct users to perform an evaluation to determine the appropriate test method based on the specific situation. Examples of possible test methods will also be provided, including, but not limited to, visual inspection, air or smoke or equivalent flow test, and draining and flushing the filled portions of the system inside containment.

DESC has evaluated the proposed amendment against the criteria set forth in 10 CFR 50.92, "Issuance of Amendment," and has determined that operation of VCSNS in accordance with the proposed amendment presents no significant hazards. The DESC evaluation against each of the criteria set forth in 10 CFR 50.92 is discussed below:

1. Does the proposed change involve a significant increase in the probability or consequences of an accident previously evaluated?

Response: No.

The spray nozzles and the associated RB spray system are designed to perform accident mitigation functions. The proposed changes do not impact the physical function of plant structures, systems, or components (SSCs) or the manner in which SSCs perform their design function. The proposed changes do not adversely affect accident initiators or precursors or alter design assumptions. The proposed changes do not alter or prevent the ability of operable SSCs to perform their intended function to mitigate the consequences of an initiating event within assumed acceptance limits. The proposed changes ensure that when maintenance or modification activities that could affect the spray nozzles are performed, measures are taken to ensure that no blockage of the nozzles has occurred.

Therefore, the proposed changes do not involve a significant increase in the probability or consequences of an accident previously evaluated.

2. Does the proposed change create the possibility of a new or different kind of accident from any accident previously evaluated?

Response: No.

The proposed changes will not impact the accident analysis. The changes do not involve a physical alteration of the plant (i.e., no new or different type of equipment will be installed), a significant change in the method of plant operation, or new operator actions.

Serial No.22-034 Docket No. 50-395 : Page 2 of 2 The changes do not make any physical modifications to the RB spray system, do not change setpoints, and do not change the method of delivering borated water to the RB spray nozzles. The proposed changes will not introduce failure modes that could result in a new accident, and do not alter assumptions made in the safety analysis.

Therefore, the proposed changes do not create the possibility of a new or different kind of accident from any accident previously evaluated.

3. Does the proposed change involve a significant reduction in a margin of safety?

Response: No.

Margin of safety is associated with confidence in the ability of the fission product barriers (i.e., fuel cladding, reactor coolant system pressure boundary, and containment structure), as well as the ability of the spray system to scrub iodine from a post-accident containment atmosphere, to limit the level of radiation dose to the public. The proposed changes do not involve a significant change in the method of plant operation, and no accident analyses will be affected by the proposed changes. Additionally, the proposed changes will not relax any criteria used to establish safety limits and will not relax any safety system settings. The safety analysis acceptance criteria are not affected by this change. The proposed changes will not result in plant operation in a configuration outside the design basis. The proposed changes do not adversely affect systems that respond to safely shutdown the plant and to maintain the plant in a safe shutdown condition.

Therefore, the proposed changes do not involve a significant reduction in a margin of safety.

Based on the above, DESC concludes that the proposed amendment does not involve a significant hazards consideration under the standards set forth in 10 CFR 50.92, and, accordingly, a finding of "no significant hazards consideration" is justified.

Conclusion Based on the considerations discussed above, (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.