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LER-2019-002, Failure of Main Steam Isolation Valve Limit Switch Results in a Condition Prohibited by Technical Specifications
Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded; 10 CFR 50.73(a)(2)(viii)(A); 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition; 10 CFR 50.73(a)(2)(viii)(B); 10 CFR 50.73(a)(2)(ix)(A); 10 CFR 50.73(a)(2)(iv)(A), System Actuation; 10 CFR 50.73(a)(2)(x); 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor; 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)(A), Completion of TS Shutdown; 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications; 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability; 10 CFR 50.73(a)(2)(i)
	2932019002R00 - NRC Website
	v • d • e

Failure of Main Steam Isolation Valve Limit Switch Results in a Condition Prohibited by Technical Specifications
	ML19065A050
Person / Time
Site:	Pilgrim
Issue date:	03/04/2019
From:	Miner P; Entergy Nuclear Operations
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	2.19.014 LER 2019-002-00
	Download: ML19065A050 (7)
	v • d • e

--- Entergx 2.19.014 March 4, 2019 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 Entergy Nuclear Operations, Inc.

Pilgrim Nuclear Power Station 600 Rocky Hill Road Plymouth, MA 02360 Peter J. Miner Manager, Regulatory Assurance 10 CFR 50.73

Subject:

Licensee Event Report 2019-002-00, Failure of Main Steam Isolation Valve Limit Switch Results in a Condition Prohibited by Technical Specifications Pilgrim Nuclear Power Station NRC Docket No. 50-293 Renewed Facility Operating License No. DPR-35 The enclosed Licensee Event Report 2019-002-00, Failure of Main Steam Isolation Valve Limit Switch Results in a Condition Prohibited by Technical Specifications, is submitted in accordance with Title 1 O Code of Federal Regulations 50.73.

There are no regulatory commitments contained in this letter.

If you have any questions or require additional information, please contact me at 508-830-7127.

Sincerely, PJM/rb

Enclosure:

Licensee Event Report 2019-002-00, Failure of Main Steam Isolation Valve Limit Switch Results in a Condition Prohibited by Technical Specifications

cEZ 2-

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Letter No. 2.19.014 Page 2 of 2 cc:

NRG Region I Regional Administrator NRG Senior Resident Inspector - Pilgrim NRG NRR Project Manager - Pilgrim

Enclosure 2.19.014 Licensee Event Report 2019-002-00, Failure of Main Steam Isolation Valve Limit Switch Results in a Condition Prohibited by Technical Specifications

BNRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 03/31/2020 (04-2017) h!!Q://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3[)

the NRG may not conduct or sponsor, and a person is not required to respond to, the information collection.

.PAGE Pilgrim Nuclear Power Station 05000-293 1 OF4

4. TITLE Failure of Main Steam Isolation Valve Limit Switch Results in a Condition Prohibited by Technical Specifications

5. EVENT DATE

6. LER NUMBER

7. REPORT DATE

8. OTHER FACILITIES INVOLVED SEQUENTIAL FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR REV MONTH DAY YEAR N/A NUMBER NO.

N/A 01 03 2019 2019

- 002

- 00 03 04 2019 FACILITY NAME DOCKET NUMBER N/A N/A

9. OPERATING MODE

11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)

N D 20.2201 (bl 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)

D 20.2203(a)(1 l D 20.2203(a)(4)

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

D 50.73(a)(2)(ix)(A)

D 20.2203(a)(2)(il 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 so.36(c)(2)

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

D 73.71 (a)(s) 35 D 20.2203(a)(2)(iv)

D so.46(a)(3)(ii)

D 50.73(a)(2)(v)(C)

D 73.77(a)(1)

D 20.2203(a)(2)(v)

D 50.73(a)(2)(i)(A)

D 50.73(a)(2)(v)(D)

D 73.77(a)(2J(il D 20.2203(a)(2)(vi)

[81 50.73(a)(2)(i)(B)

D 50.73(a)(2)(vii)

D 73.77(a)(2J(ii)

D 50.73(a)(2)(i)(C) 00THER Specify in Abstract below or in NRG Form 366A

12. LICENSEE CONTACT FOR THIS LER LICENSEE CONTACT rrLEPHONE NUMBER (Include Area Code)

[Mr. Peter J. Miner - Regulatory Assurance Manager

~08-830-7127 CAUSE SYSTEM COMPONENT MANU-REPORTABLE

CAUSE

SYSTEM COMPONENT MANU-REPORTABLE FACTURER TOEPIX FACTURER TOEPIX X

SB 33 N007 y

14. SUPPLEMENTAL REPORT EXPECTED

15. EXPECTED MONTH DAY YEAR D YES (If yes, complete 15. EXPECTED SUBMISSION DATE)

[8J NO SUBMISSION DATE ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines)

On January 5, 2019 during the performance of Main Steam Isolation Valve (MSIV) surveillance testing, control room alarm MSIV Not Full Open did not annunciate when MSIV A0-203-1 C was fully closed for stroke time testing. The MSIV Not Full Open alarm is expected when any MSIV position RPS limit switch opens. The cause was traced to failure of the MSIV position Reactor Protection System (RPS) limit switch LS6 to properly open and the associated logic system channel was placed in the tripped condition. On February 7, 2019, a detailed review of plant computer and annunciator system alarm data discovered that the MSIV position RPS limit switch LS6 did not open as expected when MSIV A0-203-1 C was closed on January 3; 2019 and the associated logic system channel was not placed in a tripped condition within the time constraints specified in Technical Specifications. The allowable action time to trip (de-energize) the RPS channel associated with failed limit switch LS6 on MSIV A0-203-1 C was exceeded because operations personnel did not correctly interpret the absence of the MSIV Not Full Open alarm upon closure of the MSIV on January 3, 2019. At the time of the event, the reactor mode selector switch was in the RUN position and the reactor was at 35 percent reactor thermal power.

This event had no impact on the health and/or safety of the public.

This report is submitted in accordance with Title 10 Code of Federal Regulations 50.73(a)(2)(i)(B); Operation or Condition Prohibited by Technical Specifications.

BACKGROUND YEAR 2019 SEQUENTIAL NUMBER

- 002 rThe Reactor Protection System (RPS) provides timely protection against the onset and consequences of conditions that threaten the integrity of the fuel clad and reactor coolant pressure boundary.

REV NO.

- 00 The Main Steam System conducts steam from the Reactor Pressure Vessel (RPV), via four steam lines,

hrough the Primary Containment to the Turbine. Each steam line has two, normally open, Main Steam Isolation Valves (MSIVs), one inside and one outside the Primary Containment. The MSIVs close automatically upon receipt of certain isolation signals.

The RPS MSIV closure signals are initiated from limit switches (valve position) located on each of the eight MS IVs. Each MSIV has two limit switches; one inputs to RPS trip system A while the other inputs to RPS trip system B. Each RPS trip system receives an input from four MSIV-closure channels, each consisting of two limit switches (one for the inboard MSIV and one for the outboard MSIV in the same steam line) in series with a sensor relay. The design permits closure of any two lines without a full scram being initiated. There are four limit switch contacts on each MSIV that provide valve stem position input for control room indication and inputs into the RPS. Limit switches 5 and 6 are closed only when the MSIV is fully open (>90 percent open) and supply the RPS circuitry.

It should be noted that prior to testing performed on January 5, 2019, there was an earlier failure of RPS limit switch LS5 on MSIV A0-203-1 C that was discovered on November 26, 2018 during testing. Upon discovery of the LS5 failure, the associated logic system channel was placed in a tripped condition. After discovering the failure of LS6 on MSIV A0-203-1 C on January 5, 2019, and placing the associated logic system channel in the tripped condition, both RPS MSIV closure channels associated with the "C" steamline MSIVs are in the tripped condition.

EVENT DESCRIPTION

On January 5, 2019 during the performance of MSIV surveillance testing, control room alarm MSIV Not Full Open did not annunciate when MSIV A0-203-1C was fully closed for stroke time testing. The MSIV Not Full Open alarm is expected when any MSIV position RPS limit switch opens. The cause was traced to failure of the MSIV position RPS limit switch LS6 to properly open and the associated logic system channel was placed in the tripped condition. On February 7, 2019, a detailed review of plant computer and annunciator

~ystem alarm data discovered that the MSIV position RPS limit switch LS6 did not open as expected when MSIV A0-203-1C was closed on January 3, 2019 at 0917 hours0.0106 days 0.255 hours 0.00152 weeks 3.489185e-4 months and the associated logic system channel was not placed in a tripped condition within the time constraints specified in Technical Specifications.

he January 3, 2019 event occurred during power operation while at 35 percent reactor power. The reactor mode selector switch was in the RUN position.

Page 2 of 4 (04-2017)

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LICENSEE EVENT REPORT (LER)

CONTINUATION SHEET (See NUREG-1022, R.3 for instruction and guidance for completing this form http://www.nrc.gov/reading-rm/doc-collections/nureqs/staff/sr1022/r3/)

, the NRG may not conduct or sponsor, and a person is not required to respond to, the information collection.

3. LEA NUMBER YEAR Pilgrim Nuclear Power Station 05000-293 2019

CAUSE OF THE EVENT

SEQUENTIAL NUMBER

- 002 REV NO.

- 00 On January 3, 2019, both "C" steamline MSIVs were closed during normal low power operations as directed by operating procedure. RPS MSIV closure logic system testing was not being performed. Upon closure of MSIV A0-203-1C the MSIV Not Full Open alarm did not annunciate. The allowable action time to trip (de-energize)

~he RPS channel associated with failed limit switch LS6 on MSIV A0-203-1 C was exceeded because operations personnel did not correctly interpret the absence of the MSIV Not Full Open alarm upon closure of

~he MSIV on January 3, 2019.

CORRECTIVE ACTIONS

MSIV A0-203-1 C RPS limit switches are located in the Primary Containment and are not accessible during plant operations. It is our intention to initiate troubleshooting of the condition should an outage of sufficient duration and scope occur.

!Any further corrective actions will be documented in the corrective action program.

SAFETY CONSEQUENCES

rThere were no actual consequences to safety of the general public, nuclear safety, industrial safety, or radiological safety for this event since the MSIV closure scram function within the RPS is designed to accommodate single failure within the logic system and therefore was capable of performing its intended safety

~unction during this event.

REPORT ABILITY The NRC Operations Center was notified of the condition discovered on January 5, 2019 in accordance with [Title 10 Code of Federal Regulations (CFR) 50.72 (b)(3)(v) "Any event or condition that could have prevented

~he fulfillment of the safety function of structures or systems that are needed to: (A) Shut down the reactor and maintain it in a safe shutdown condition" at 1730 hours0.02 days 0.481 hours 0.00286 weeks 6.58265e-4 months via Event Number 53815. This 10 CFR 50.72 notification was subsequently retracted on February 11, 2019 based on an Engineering Evaluation that concluded that the MSIV position RPS logic was capable of performing its intended safety function.

Subsequent evaluation determined that the failure of limit switch LS6 on MSIV A0-203-1 C is reportable under 1 O CFR 50.73{a)(2)(i)(B) as a condition prohibited by Technical Specifications since the Technical Specification Required Action of Note 1 for Table 3.1.1, Condition a. to place the affected channel in a tripped condition, did not meet the Completion Time of 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months .

PREVIOUS EVENTS There have been no events reported in the last three years related to failure of MSIV limit switches.

Page 3 of 4 (04-2017)

U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 3/31/2020

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f....... +d' LICENSEE EVENT REPORT (LER)

CONTINUATION SHEET (See NUREG-1022, R.3 for instruction and guidance for completing this form http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/@)

, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.

3. LER NUMBER Pilgrim Nuclear Power Station REFERENCES Condition Report CR-PNP-2019-00084 Condition Report CR-PNP-2019-00090 Condition Report CR-PNP-2019-00838 YEAR 05000-293 2019 SEQUENTIAL NUMBER

- 002 REV NO.

- 00 Page 4 of 4

05000293/LER-2019-002, Failure of Main Steam Isolation Valve Limit Switch Results in a Condition Prohibited by Technical Specifications

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