05000395/LER-2019-001-01, Regarding Condition Prohibited by Technical Specification 3.4.6.1

Regarding Condition Prohibited by Technical Specification 3.4.6.1

ML19231A343
Person / Time
Site:	Summer
Issue date:	08/19/2019
From:	Lippard G Dominion Energy South Carolina, South Carolina Electric & Gas Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
LER 2019-001-01
Download: ML19231A343 (5)

LER-2019-001, Regarding Condition Prohibited by Technical Specification 3.4.6.1

Event date:
Report date:
3952019001R01 - NRC Website

text

V. C. Summer Nuclear Station Bradham Blvd & Hwy 215, Jenkinsville, SC 29065 Mailing Address:

P.O. Box 88, Jenkinsville, SC 29065 Dominion Energy.com Document Control Desk August19, 2019 U.S. Nuclear Regulatory Commission Washington, DC 20555 SOUTH CAROLINA ELECTRIC & GAS COMPANY

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Dominion

iiiiii" Energy Serial No. 19-171A VCS-LIC/JRB RO Docket No. 50-395 License No. NPF-12 VIRGIL C. SUMMER NUCLEAR STATION (VCSNS) UNIT 1 LICENSEE EVENT REPORT 2019-001-01 CONDITION PROHIBITED BY TECHNICAL SPECIFICATION 3.4.6.1 Enclosed is Licensee Event Report (LER) 2019-001-01, for the Virgil C. Summer Nuclear Station. This report provides details concerning a past condition prohibited by Technical Specification (TS) 3.4.6.1. This revision to LER 2019-001-00 addresses NRC Finding 2019001-02 (CR-19-02144). This report is submitted pursuant to 10 CFR 50. 73(a)(2)(i)(B).

In a letter dated July 30, 2019 (ML19214A046), South Carolina Electric & Gas Company (SCE&G) requested a License Amendment to amend the V. C. Summer operating license to reflect the name change from SCE&G to Dominion Energy South Carolina (DESC). The amendment request is currently under review by the NRC.

Should you have any questions, please call Mr. Michael Moore at (803) 345-4752.

Sincerely, Georg A Lippard Site Vice President V.C. Summer Nuclear Station Enclosure Commitments contained in this letter: None cc:

G. J. Lindamood - Santee Cooper L. Dudes - NRC Region II S. A. Williams - NRC Project Mgr.

NRC Resident Inspector J. N. Bassett-lNPO Marsh USA, Inc.

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 03/31/2020 (04-2018)

Estimated burden per response ID comply with this mandato,y collection request: 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />.

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LICENSEE EVENT REPORT (LER)

Reported lessoos learned are incorporated into the licensing process and fed back ID industry. Send comments regarding burden estimate to the Information Services Branch

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(T-2 F43), U.S. Nudear Regulatory Commission, Washington, DC 20555-0001, or by e-mail I!

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{See Page 2 for required number of digits/characters for each block) lo lnfocollects.Resource@nrc.gov, and lo the Desk Officer, Office of lnfonnation and 0

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C Regulalo,y Affairs, NEOB-10202, (3150-0104), Office or Management and Budget, (See NUREG-1022, R.3 for instruction and guidance for completing this form c:.

.I Washington, DC 20503. If a means used to impose an information collection does not

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i-htti;i;//www.o[c,gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3/)

display a currently valid OMS control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.

3.Page V.C. Summer Nuclear Station, Unit 1 05000 395 1

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4. Title CONDITION PROHIBITED BY TECHNICAL SPECIFICATION 3.4.6.1

5. Event Date

6. LER Number

7. Report Date

8. Other Facilities Involved I

Sequential I Rev Facility Name Docket Number Month Day Year Year Number No.

Month Day Year 05000 Facility Name Docket Number 12 6

2018 2019.

001 01 8

19 2019 05000

9. Operating Mode

11. This Report is Submitted Pursuant to the Requirements of 10 CFR §: (Check all that apply)

D 20.2201{b)

D 20.2203{a){3){i)

D 50. 73{a)(2){ii)(A)

D 50. 73(a)(2)(viii)(A)

D 20.2201{d)

D 20.2203{a){3){ii)

D 50. 73(a)(2)(ii){B)

D 50. 73{a){2)(viii){B) 1 D 20.2203{a){1)

D 20.2203{a){4)

D 50. 73(a)(2)(iii)

D 50. 73(a)(2)(ix)(A)

D 20.2203{a){2)(i)

D 50.36{c)(1 ){i)(A)

D 50. 73{a)(2)(iv)(A)

D 50. 73{a)(2)(x)

10. Power Level D 20.2203{a){2)(ii)

D 50.36{c)(1 )(ii){A)

D 50. 73(a)(2){v)(A)

D 73.71{a)(4)

D 20.2203{a)(2)(iii)

D 50.36{c)(2)

D 50.73{a)(2)(v)(B)

D 73.71{a)(5)

D 20.2203{a){2){iv)

D 50.46{a){3){ii)

D 50.73{a){2){v){C)

D 73.77{a)(1) 100 D 20.2203{a){2)(v)

D 50. 73{a)(2)(i)(A)

D 50. 73{a){2){v){D)

D 73. 77(a){2){i)

D 20.2203{a)(2)(vi) 0 50.73{a){2){i){B)

D 50.73{a){2){vii)

D 73. 77(a){2){ii)

D 50. 73{a)(2){i){C)

D Other (Specify in Abstract below or in

2.0 EVENT ANALYSIS

During RF24, it was identified that biological growth in the RBCU condensate drain sensing lines was obstructing flow.

Previous cleaning efforts did not include removal of RBCU condensate drain valves that collected debris and acted as flow choke points. The restricted flow of condensate created an environment that promoted algae growth. As a result, this algae and other debris within the drain sensing lines impacted flow to the RBCU condensate drain flow switches, causing inoperable flow switches (both IFS01900A and IFS01900B) during CY24, as described below. With the installation of the new RB chiller system in preparation for RF23, the industrial cooling water supplied to the RBCU coils is now colder than the original design, resulting in increased moisture removal by the RBCUs. This larger volume of condensate is thought to be a contributor to the increased amount of algae growth over the past cycle.

I VCSNS completed RF23 on June 1, 2017 and entered normal power operations. On September 16, 2017, RBCU condensate flow switch 'A' (IFS01900A) was declared inoperable and removed from service. IFS01900A had experienced a locked in HI alarm without condensate flow present due to algae and other debris in the RBCU drain sensing line, which could not be corrected during power operation. VCSNS credited IFS01900B to meet TS LCO 3.4.6.1 for the remainder of the cycle.

RBCU condensate flow switch 'B' (IFS01900B) was discovered inoperable on October 29, 2018, during RF24.

IFS01900B was found to not respond when flow was introduced to the switch using the demineralized water system, due to algae and other debris present in the RBCU drain sensing line. A past operability determination was performed and on December 6, 2018, it was concluded that the switch could not have been relied on to actuate during the previous cycle.

Therefore, it was conservatively determined to consider IFS01900B inoperable during the past cycle (June 1, 2017 to October 6, 2018).

As a result of the past operability determination for IFS01900B and the concurrent inoperability of IFS01900A, VCSNS did not have an operable RBCU condensate flow rate monitor, as required by TS LCO 3.4.6.1, from September 16, 2017 to October 6, 2018.

Evaluation of station compliance with LCO 3.4.6.1 and associated TS Actions initially determined that the required actions were implemented by normal operations procedures, including Surveillance Test Procedure STP-114.002, Operational Leakage Calculation. However, further review determined that VCSNS did not comply with TS 3.4.6.1 Action c for short periods of time between September 16, 2017 and October 6, 2018. Consequently, the plant operated in a I

condition prohibited by TS, which is reportable under 10 CFR 50. 73(a)(2)(i)(B).

During RF24, VCSNS Unit 1 implemented new cleaning and maintenance practices, restored operability of both IFS01900A and IFS01900B, and has exited TS 3.4.6.1 Action c.

Since the submittal of LER 2019-001-00, IFS01900B has been removed from service. During performance of a routinely-performed Reactor Building Cooling Unit Functional and Iodine Removal System Test on May 25, 2019, IFS01900B came into alarm, but did not clear when the test was complete as was expected. This condition was documented in CR-19-01939. While IFS01900A is still operable, VCSNS has elected to conservatively implement TS 3.4.6.1 Action c requirements until operability of IFS01900B is restored.

VCSNS is pursuing opportunities to improve reliability during RF25.

3.0 SAFETY SIGNIFICANCE

There was no quantified risk impact from this event. The Probabilistic Risk Assessment does not model the RBCU condensate drain flow switches or credit the function. Two diverse methods of leak detection were operable at the time of the missed action. Channel checks of the RB atmospheric radiation monitor were performed approximately I every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> with satisfactory results. RB sump level instrumentation was available without interruption.

4.0 PREVIOUS OCCURRENCE There have been no other instances of TS violations related to leak detection systems in containment during the past three (3) years.

It is noted that this event is similar to LER 2007-003-01, which documents a previous TS violation due to clogging of IFS01900A and IFS01900B due to inorganic foreign material within the drain lines. CR-19-02143 is evaluating the ineffectiveness of the corrective actions associated with the event documented by LER 2007-003-01 in preventing this event.

5.0 CORRECTIVE ACTIONS

VCSNS implemented corrective actions during RF24 following discovery of the obstructed condensate drain line and is investigating opportunities for improved reliability to be implemented during RF25.

During RF24, inspection and cleaning techniques were refined and utilized to restore both RBCU condensate flow switches. Station procedure MMP-460.038, Revision 1 "Inspection, Cleaning, and Lubrication of Reactor Building Cooling Units XAA0001A/B and XAA0002A/B" has been updated to include the added cleaning techniques of the flow switches. MMP-460.038, Revision 1 added a new section, Section 7.3 and Attachment II for cleaning RBCU drain lines. This technique includes ensuring the inside of all piping around IFS01900A and IFS01900B is scrubbed to remove the buildup, soaked with hydrogen peroxide, and flushed with demineralized water multiple times. The lines are then inspected to verify cleanliness and to ensure that there are no obstructions remaining.

In addition to the refined techniques used, the pipe cleaning boundary upstream of the flow switches has been expanded to areas that were not previously included in the inspection or cleaning. This includes physical and chemical cleaning of the drain line trap and sensing lines that direct flow to the RBCU condensate flow switches.

Plant engineers developed the new expanded cleaning boundary and techniques.

I Implementation of the expanded and refined inspection and cleaning techniques cleared the drain sensing line obstruction. Testing performed confirmed flow switch operability for both IFS01900A and IFS01900B, indicating that both would have operated as expected if the line had not been obstructed.

In preparation for the upcoming RF25 outage (Spring 2020), VCSNS is investigating opportunities to improve RBCU I

condensate flow monitoring. Page 4

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