05000395/LER-2019-001, Condition Prohibited by Technical Specification 3.4.6.1
| ML19105B284 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 04/15/2019 |
| From: | Lippard G South Carolina Electric & Gas Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 19-171 LER 2019-001-00 | |
| Download: ML19105B284 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(i) |
| 3952019001R00 - NRC Website | |
text
A SCANA COMPANY April 15, 2019 Document Control Desk.
U.S. Nuclear Regulafory Commission Washington, DC 20555 SOUTH CAROLINA ELECTRIC & GAS COMPANY Serial No.19-171 VCS-LIC/JRB RO Docket No. 50-395 License No. NPF-12 VIRGIL C. SUMMER NUCLEAR STATION (VCSNS) UNIT 1 LICENSEE EVENT REPORT 2019-001-00 CONDITION PROHIBITED BY TECHNICAL SPECIFICATION 3.4.6.1 Enclosed is Licensee Event Report (LER) 2019-001-00, for the Virgil C. Summer Nuclear Station. This report provides details concerning a past condition prohibited by Technical Specification 3.4.6.1. This report is submitted pursuant to 10 CFR 50. 73(a)(2)(i)(B).
The event described in this LER occurred greater than sixty (60) days ago. The timeliness of this report is being addressed in the VCSNS Corrective Action Program by condition report CR-19-01287.
Should you have any questions, please call Mr. Michael Moore at (803) 345-4752.
~incerely, Enclosure Commitments contained in this letter: None cc:
G. J. Lindamood - Santee Cooper C. Haney - NRC Region II S. A. Williams - NRC Project Mgr.
NRC Resident Inspector J. N. Bassett-INPO Marsh USA, Inc.
- i I
V. C. Summer Nuclear Station* P. 0. Box 88
- Jenkinsville, South Carolina* 29065
- F (803) 941-9776
- www.sceg.com
NRG FORM 366 U.S. NUCLEAR REGULA TORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 03/31/2020 (04-2018)
, the NRG may not conduct or sponsor, and a
- ii:"'
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 Dato
- 6. LER Number
- 7. Report Date
- 8. Other Facilities Involved Month Day Year Year I Sequential I Rev Facility Name Docket Number Number No.
Month Day Year 05000 Facility Name Docket Number 12 6
2018 2019 -
001 -
00 4
15 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) 1 D 20.2201(d)
D 20.2203(a)(3)(ii)
D 50.73(a)(2)(ii)(B)
D 50. 73(a)(2)(viii)(B)
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 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 during power ascension following a reactor trip on November 7, 2017. STP-114.002 work orders for November 10 and 11, 2017 were closed without being performed due to the plant transient. Therefore, the plant operated in a 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.
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 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. However, this event differed from the event described in LER 2007-003-01 due to the failure mechanism. LER 2007-003-01 captures failure of the RBCU condensate flow switches due to inorganic foreign material within the drain lines.
5.0 CORRECTIVE ACTIONS
Inspection and cleaning techniques were refined and utilized to restore both RBCU condensate flow switches during RF24. 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, and concluded that implementation of the new methodology provides reasonable assurance of flow switch operability.
Implementation of the expanded and refined inspection and cleaning techniques cleared the drain sensing line obstruction. Testing petiormed confirmed flow switch operability for both IFS01900A and IFS01900B, indicating that both would have operated as expected if the line had not been obstructed. Page 4
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