05000293/LER-2011-007, From Pilgrim Nuclear Power Station Safety Relief Valve Declared Inoperable Due to Leakage

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From Pilgrim Nuclear Power Station Safety Relief Valve Declared Inoperable Due to Leakage
ML12062A054
Person / Time
Site: Pilgrim
Issue date: 02/23/2012
From: Dodds R
Entergy Nuclear Operations
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
LER 11-007-00
Download: ML12062A054 (7)
v • d • e


LER-2011-007, From Pilgrim Nuclear Power Station Safety Relief Valve Declared Inoperable Due to Leakage
Event date:
Report date:
Reporting criterion: 10 CFR 50.73(a)(2)(i)
10 CFR 50.73(a)(2)(vii), Common Cause Inoperability
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)(iii)
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)(i)(A), Completion of TS Shutdown
10 CFR 50.73(a)(2)(v), Loss of Safety Function
10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
2932011007R00 - NRC Website
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text

AEntergy Entergy Nuclear Operations, Inc.

Pilgrim Nuclear Power Station 600 Rocky Hill Road Plymouth, MA 02360 Ralph A. Dodds, III Director, Nuclear Safety Assurance February 23, 2012 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555

SUBJECT:

Entergy Nuclear Operations, Inc.

Pilgrim Nuclear Power Station Docket No.: 50-293 License No.: DPR-35 Licensee Event Report 2011-007-00, Safety Relief Valve Declared Inoperable Due to Leakage LETTER NUMBER: 2.12.013

Dear Sir or Madam:

The enclosed Licensee Event Report (LER) 2011-007-00, "Safety Relief Valve Declared Inoperable Due to Leakage" is submitted in accordance with 10 CFR 50.73.

This letter contains no commitments.

Please do not hesitate to contact Mr. Joseph R. Lynch, (508) 830-8403, if there are any questions regarding this submittal.

Sincerely, A Dkoaýý T-u Ralph A. Dodds, III : Licensee Event Report 2011-007-00, Safety Relief Valve Declared Inoperable Due to Leakage mz

PNPS Letter 2.12.013 Page 2 of 2 cc:

Mr. William M. Dean Regional Administrator, Region 1 U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406-1415 INPO Records 700 Galleria Parkway Atlanta, GA 30399-5957 Mr. Richard V. Guzman, Project Manager Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Stop O-8-C2 11555 Rockville Pike Rockville, MD. 20852 USNRC Senior Resident Inspector Pilgrim Nuclear Power Station Letter Number 2.12.013 Licensee Event Report 2011-007-00 Safety Relief Valve Declared Inoperable Due to Leakage (4 Pages)

"NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2013 (10-2010)

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

Reported lessons learned are incorporated into the licensing process and fed back to industry.

Send comments regarding burden estimate to the FOIA/Privacy Service Branch (T-5 F53), U.S.

Nuclear Regulatory Commission, Washington, DC 20555-0001, or by intemet e-mail to LICENSEE EVENT REPORT (LER) infocollects.resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503.

If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.

3. PAGE Pilgrim Nuclear Power Station 05000293 1 OF4
4. TITLE Safety Relief Valve Declared Inoperable Due to Leakage
5. EVENT DATE
6. LER NUMBER
7. REPORT DATE
8. OTHER FACILITIES INVOLVED RE FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR SEQUENTIAL V

MONTH DAY YEAR N/A NUMBER N

FACILITY NAME DOCKET NUMBER 12 26 2011 2011 007 00 2

23 2012 N/A

9. OPERATING MODE
11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) 20.2201(b) 20.2203(a)(3)(i) 50.73(a)(2)(i)(C) 50.73(a)(2)(vii)

N 20.2201 (d) 20.2203(a)(3)(ii) 50.73(a)(2)(ii)(A) 50.73(a)(2)(viii)(A) 20.2203(a)(1) 20.2203(a)(4) 50.73(a)(2)(ii)(B) 50.73(a)(2)(viii)(B) 20.2203(a)(2)(i) 50.36(c)(1)(i)(A) 50.73(a)(2)(iii) 50.73(a)(2)(ix)(A)

_ 20.2203(a)(2)(ii) 50.36(c)(1)(ii)(A) 50.73(a)(2)(iv)(A) 50.73(a)(2)(x)

10. POWER LEVEL 20.2203(a)(2)(iii) 50.36(c)(2) 50.73(a)(2)(v)(A) 73.71 (a)(4) 20.2203(a)(2)(iv) 50.46(a)(3)(ii) 50.73(a)(2)(v)(B) 73.71 (a)(5) 20.2203(a)(2)(v) 50.73(a)(2)(i)(A) 50.73(a)(2)(v)(C)

OTHER 100%

20.2203(a)(2)(vi) 50.73(a)(2)(i)(B) 50.73(a)(2)(v)(D)

Specify in Abstract below or in

EVENT DESCRIPTION

On December 26, 2011 at 10:46 EST while operating at 100% power, the near tailpipe temperature for safety relief valve (SRV) RV-203-3D increased from an ambient temperature in the range of 160°F to greater than 2000F. A review of thermocouples installed in RV-203-3D confirmed a pilot stage (first stage) leak resulting in the valve being declared inoperable and an unplanned LCO entry leading to a plant shutdown.

The Pilgrim Nuclear Reactor Pressure Vessel Relief System consists of four safety relief valves (SRVs) and two spring safety valves (SSVs). During Refueling Outage (RFO-1 8), in April/May, 2011, the four SRVs were replaced with Target Rock Model 0867F 3-stage SRVs.

To monitor these valves for leakage, Pilgrim installed thermocouples at the pilot (first stage), at the second stage, on the tailpipe near the valve (4.5' to 6' away), on the tailpipe far from the valve (-20' away) and at the pilot bellows. Procedure 2.2.23, "Automatic Depressurization System", provides guidance for interpreting the thermocouple outputs and determination of valve operability based in part on testing performed by Target Rock.

On December 26, 2011, the Control Room received alarm "Relief/Safety Valve Leaking (C903L-A2)". The pilot stage temperature decreased by 65 0F from its baseline temperature and the second stage temperature decreased by about 1 0°F. Based on the Target Rock data, this indicated that there was leakage that required repair of the SRV.

The safety relief valve was subsequently declared inoperable and the Limiting Condition for Operation (LCO) for Technical Specification (TS) 3.6.D was entered. Due to the valve being declared inoperable, the station was required to be shutdown and reactor coolant pressure below 104 psig within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> per T.S. 3.6.D.2.

ROOT CAUSE OF EVENT:

The SRVs were purchased new, installed, and tested for the first time in May 2011 during RFO-18. As such, to determine the root cause, disassembly and inspection of the pilot at Wyle Laboratories must be completed. A joint team of Wyle Laboratories, Target Rock, and Entergy engineering are working together to disassemble and inspect the pilot to determine the root cause of the leakage.

At this time the most probable root causes are problems during the initial manufacturing and/or assembly of the pilot at Target Rock prior to installation at the site.

Wyle Laboratories, Target Rock, and Entergy will identify any errors in the manufacturing or assembly of the pilot during disassembly and inspection of the valve and complete the root cause evaluation with that information.

CONTRIBUTING CAUSES OF EVENT:

There are no contributing causes identified at this time.U.S. NUCLEAR REGULATORY COMMISSION (10-2010)

LICENSEE EVENT REPORT (LER)

CONTINUATION SHEET

1. FACILITY NAME
2. DOCKET
6. LER NUMBER
3. PAGE SEQUENTIAL REV YEAR Pilgrim Nuclear Power Station 05000293 NUMBER NO.

3 OF 4 2011-007 00 EXTENT OF CONDITION:

The identified condition is a leaking SRV pilot. Based on a review of plant data, the only pilot to exhibit signs of leakage is RV-203-3D. The leaking pilot has been replaced. No additional pilots have this condition at this time.

Any corrective actions that are identified to prevent reoccurrence of leaking SRV pilots will be applied to all four SRVs.

CORRECTIVE ACTIONS

The following corrective actions were completed.

The pilot stage of RV-203-3D was removed. The pilot from another valve assembly which was verified to be leak tight was used.

Additional corrective actions, if required, will be implemented based upon the results of the testing, inspection, and evaluation of the leaking pilot from RV-203-3D by a joint team of Wyle Laboratories, Target Rock, and Entergy Engineering.

ASSESSMENT OF SAFETY CONSEQUENCES

The leaking SRV and the plant shutdown to repair the SRV in accordance with Technical Speciation 3.6.D.2 posed no threat to the public health and safety.

All leakage from the valve was collected in plant systems, primarily the torus, and processed in accordance with normal station practices.

Pilgrim designed the SRVs and the installed temperature monitoring, to provide sufficient indication of SRV leakage so that appropriate actions can be taken to ensure that the plant is maintained in a safe condition.

Procedure 2.2.23 provides the instructions and guidance for interpreting and responding to SRV temperature indications. Based on these instructions, the plant was shutdown before the leakage could increase to the point that the valve might self-actuate. Because the leakage established by procedure did not affect the SRV set pressure or capacity, the SRV would have been able to respond if needed to meet its core cooling or reactor pressure vessel overpressure protection functions.

PREVIOUS OCCURRENCES

There are no previous first stage leakage occurrences with these safety relief valves since all four Safety Relief Valves were newly installed in April/May, 2011, during Refueling Outage 18.

However, the industry has experienced leakage with other Target Rock Model safety relief valves at other plants.

OE26394 & OE26892 - Planned Shutdown due to a Safety Relief Valve Leak - Peach Bottom Unit 3U.S. NUCLEAR REGULATORY COMMISSION (10-2010)

LICENSEE EVENT REPORT (LER)

CONTINUATION SHEET

1. FACILITY NAME
2. DOCKET
6. LER NUMBER
3. PAGE YEAR SEQUENTIAL REV Pilgrim Nuclear Power Station 05000293 1

NUMBER NO.

4 OF 4 2011-007 00 0E33766 - Three Stage Safety Relief Valve Pilot Leakage just below, Normal Operating Pressure - Plant Hatch OE32805 - Safety Relief Valve Temperature Phenomenon - Fitzpatrick OE34730 - Target Rock 3 Stage Main Steam SRV Bore to Seat Misalignment - Limerick 2 OE19219 - Plant Shutdown Due to Increasing Tailpipe Temperature - Duane Arnold ENERGY INDUSTRY IDENTIFICATION SYSTEM (EIIS) CODES:

COMPONENTS CODES Valve, Relief RV SYSTEMS Main Steam SB

REFERENCES:

Condition Report CR-PNP-2011-5870, Safety Relief Valve RV-203-3D, Pilot Leak Root Cause Evaluation Report

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