05000333/LER-2017-004-01, Regarding Safety Relief Valves Out of Tolerance
| ML18089A040 | |
| Person / Time | |
|---|---|
| Site: | FitzPatrick  |
| Issue date: | 03/30/2018 |
| From: | Timothy Peter Exelon Generation Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| JAFP-l8-0033 LER 2017-004-01 | |
| Download: ML18089A040 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(v), Loss of Safety Function 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)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i) |
| 3332017004R01 - NRC Website | |
text
Exeton Generation JAFP-l 8-0033 March 30, 2018 United States Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555-0001 Exelon Generation company, LLC James A. FitzPatrick NPP P.O. Box 110 Lycoming, NY 13093 Tel 31 5-349-6024 Fax 31 5-349-6480 Timothy c. Peter Plant Manager JAF
Subject:
Dear Sir or Madam:
LER: 2017-004-01, Safety Relief Valves Out of Tolerance James A. FitzPatrick Nuclear Power Plant NRC Docket No. 50-333 Renewed Facility Operating License No. DPR-59 This report is being submitted pursuant to 10 CFR 50.73(a)(2)(i)(B) and 10 CFR 50.73(a)(2)(v)(D) as an Operation or Condition Prohibited by Technical Specifications and Event or Condition that Could Have Prevented Fulfillment of a Safety Function, respectively.
There are no new regulatory commitments contained in this report.
Questions concerning this report may be addressed to Mr.
Assurance Manager, at (315) 349-6562.
William Drews, Regulatory
Enclosure:
LER: 2017-004-01, Safety Relief Valves Out of Tolerance cc:
USNRC, Region I Administrator USNRC, Project Manager USNRC, Resident Inspector INPO Records Center (ICES)
/
Sincerely, Plant Manager TCPJWD/ds
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 0313112020 (04-2017)
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 and Information Collechons Branch (T LICENSEE EVENT REPORT (LER) 5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to Infocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, (See Page 2 for required number of digits/characters for each block)
NEOB-1 0202, (31 50-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid 0MB control number, the (See NUREG-1 022, R.3 for instruction and guidance for completing this form NRC may not conduct or sponsor, and a person is not required to respond to.
the information http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3/)
collechon.
- 3. PAGE James A. FitzPatrick Nuclear Power Plant 05000333 1 OF 4
- 4. TITLE Safety Relief Valves Out of Tolerance
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED SEQUENTIAL REV FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR NUMBER NO MONTH DAY YEAR N/A N/A FACILITY NAME DOCKET NUMBER 11 21 2017 2017 004 01 03 30 2018 N/A N/A
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)
El 20.2201(b)
[] 20.2203(a)(3)(i)
[] 50.73(a)(2)(ii)(A)
El 50.73(a)(2)(viii)(A) 1 El 20.2201(d)
El 20.2203(a)(3)(ii)
El 50.73(a)(2)(ii)(B)
El 50.73(a)(2)(viii)(B)
[1 20.2203(a)(1)
El 20.2203(a)(4)
[] 50.73(a)(2)(iii)
[] 50.73(a)(2)(ix)(A)
[] 20.2203(a)(2)(i)
[] 50.36(c)(1)(i)(A) j] 50.73(a)(2)(iv)(A)
[] 50.73(a)(2)(x)
JO. POWER LEVEL El 20.2203(a)(2)(ii)
El 50.36(c)(1)(ii)(A)
El 50.73(a)(2)(v)(A)
El 73.71(a)(4)
El 20.2203(a)(2)(iii) 50.36(c)(2) 50.73(a)(2)(v)(B) 73.71(a)(5) j 20.2203(a)(2)(iv) 50.46(a)(3)(ii) jJ 50.73(a)(2)(v)(C) 73.77(a)(1) 100
[] 20.2203(a)(2)(v)
[] 50.73(a)(2)(i)(A) 50.73(a)(2)(v)(D)
[J 73.77(a)(2)(i) 20.2203(a)(2)(vi) 50.73(a)(2)(i)(B)
El 50.73(a)(2)(vii) 50.73(a)(2)(i)(C)
El OTHER Specify in Abstract below or in NRC Form 366A
- 12. LICENSEE CONTACT FOR THIS LER LICENSEE CONTACT TELEPHONE NUMBER (Include Area Code)
Mr. William Drews, Regulatory Assurance Manager 315-349-6562MANU-REPORTABLE MANU-REPORTABLE
CAUSE
SYSTEM COMPONENT FACTURER TO EP1X
CAUSE
SYSTEM COMPONENT FACTURER TO EPIX B
SB RV T020 Y
- 14. SUPPLEMENTAL REPORT EXPECTED
- 15. EXPECTED MONTH DAY YEAR SUBMISSION YES (Ifyes, complete 75. EXPECTED SUBMISSION DATE)
NO DATE ABSTRACT (Limit to 7400 spaces, i.e., approximately 15 single-spaced typewritten lines)
The As-Found test results for the eleven Safety/Relief Valve (S/RV) pilot assemblies removed and replaced during the 2017 Refueling Outage at James A. FitzPatrick Nuclear Power Plant (JAF) identified ten (10) S/RV pilot assemblies that lifted outside of the allowable tolerance required by Technical Specification Surveillance Requirement 3.4.3.1. Nine (9) two-stage S/RVs were found out of tolerance high, and one three-stage was found out of tolerance low. The ten S/RV pilot assemblies are assumed to have been inoperable at some point in the operating cycle that preceded the 2017 Refueling Outage resulting in a condition reportable pursuant to 10 CFR 50.73(a)(2)(i)(B).
The S/RV design features an electric actuation capability that provides a diversified means of opening the S/RVs despite the out of tolerance condition. However, the electric lift function is considered a backup to the mechanical S/RVs and is not credited in the accident analysis. Therefore, the TS inoperability of the ten (10) S/RVs also resulted in a condition reportable pursuant to 10 CFR5O.73(a)(2)(v)(D).
The cause of the two-stage failures has been identified as corrosion bonding; the cause of the three-stage failure is attributed to calibration and subsequent setpoint drift. The safety consequences associated with this event are considered low due to the electric actuation capability.
NRC FORM 366 (06-2016)
=
Background===
The ASME Boiler and Pressure Vessel Code requires the reactor pressure vessel be protected from overpressure during upset conditions by self-actuated safety valves. As part of the nuclear pressure relief system, the size and number of SIRVs are selected such that peak pressure in the Reactor Coolant Pressure Boundary (RCPB) will not exceed the ASME Code limits.
The James A. FitzPatrick Nuclear Power Plant (JAF) used ten (10) two-stage and one (1) three-stage Target Rock Safety/Relief Valves (S/RV) [EIIS Identifier: SB] for emergency pressure relief during operating Cycle 22.
These valves are located on the main steam lines between the reactor vessel, and the first isolation valve within the drywell. Each S/RV discharges steam through a discharge line to a point below the minimum water level in the suppression pool.
The S/RVs can actuate by either of two modes: the safety mode or the relief mode. In safety mode (or spring mode of operation), the spring-loaded pilot valve opens when steam pressure at the valve inlet overcomes the spring force holding the pilot valve closed. Opening the pilot valve allows a pressure differential to develop across the main valve piston and opens the main valve. This satisfies the code requirement.
Each S/RV can be opened manually in the relief mode from the control room by its associated two-position switch. If one of these switches is placed in the open position the logic output will energize the associated S/RV solenoid control valve directing the pneumatic supply to open the valve. Seven of the installed S/RV solenoid control valves can also be energized by the relay logic associated with the Automatic Depressurization System (ADS).
During each refueling outage all eleven of the pilot assemblies are removed and replaced with vendor tested and certified components. The pilots that are removed are sent to a vendor facility for testing, refurbishment, and certification. The test results for pilot assemblies removed in 2017, during Refueling Outage 22, identified ten (10) S/RV pilot assemblies that were out of allowable tolerance. Nine (9) of the pilots (all two-stage) lifted at greater than the allowable setpoint range, and one (three-stage) lifted at less than the allowable setpoint range.
In order to address the concerns with corrosion bonding, JAF will commence replacement of two-stage with three-stage Target Rock S/RVs in the next Refueling Outage (RO). Industry experience has shown that the three stage S/RVs are less susceptible to corrosion bonding. The design of the three-stage S/RVs produces a greater mechanical force on opening, resulting in a greater likelihood of overcoming any potential effects of corrosion bonding that might occur.
Event Description
As-Found testing was performed on all eleven main S/RV pilot assemblies removed in 2017, during R022.
The testing was conducted by NWS Technologies. The TS setpoint for each S/RV is 1145 +1-34.3. During the initial lift test, ten of the eleven pilot assemblies failed to open within the allowable range (1110.7 to 1179.3).
Nine of the ten two-stage and the three-stage S/RV pilot failed high and low outside the allowable range, respectively. As-Found failed test results are tabulated below.Page 2 of 4U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 03131/2020 (04-2017)
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 LICENSEE EVENT REPORT (LER) lessons learned are incorporated into the licensing process and fed back to industry. Sendcomments
CONTINUATION SHEET regarding burden estimate to the FOIA, Privacy and Information Collections Branch (1-5 F53), U.S.
Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to
/
lnfocoIlects.Resourcenrc.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 0MB control number, the (See NUREG-1 022, R.3 for instruction and guidance for completing this form NRC may not conduct or sponsor, and a person is not required to respond to, the informahon collechon.
http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/srl 022Ir3I)
- 3. LER NUMBER YEAR SEQUENTIAL REV James A. FitzPatrick Nuclear Power Plant 05000 333 NUMBER NO.
2017 004 01 Table 1 As-Found Test Results In-service Pilot Serial First Test Acceptance Range Location Number (psig)
(1110.7 1179.3 psig)
O2RV-71A 1088 1184 UnsatHigh O2RV-71B 1080 1254 UnsatHigh 02RV71C(a) 51 1103 UnsatLow O2RV-71E 1235 1245 UnsatHigh O2RV-71F 1195 1183 UnsatHigh O2RV-71G 1194 1202 UnsatHigh O2RV-71H 1111 1228 UnsatHigh O2RV-71J 1192 1242 UnsatHigh O2RV-71K 1193 1239 UnsatHigh O2RV-71L 1056 1214 Unsat-High (a)Three.Stage
Cause
JAF has extensive internal Operating Experience with the S/RVs failing higher than the allowable setpoint.
Causal evaluations identified corrosion bonding as the cause for the upward setpoint drift on the two-stage S/RVs. The As-Found test results shown above in conjunction with the successful second lift of all two-stage valves support this conclusion. Corrosion bonding is a crevice corrosion phenomenon that occurs between highly polished metals in a wetted solution in close proximity to each other. This close proximity (usually a gap of between 0.1 and 100 iJm) creates a crevice-like condition between the two wetted surfaces setting up the conditions for crevice corrosion to occur. An oxygen rich environment is created by the accumulation of oxygen in the area of the pilot disc due to the breakdown of water into hydrogen and oxygen. Susceptible material in the tight geometry with exposure to oxygen and high temperatures are the conditions which cause corrosion bonding in JAF S/RVs. There is extensive industry experience with corrosion bonding in the Target Rock two-stage S/RVs pilot assemblies.
As stated above, the three-stage S/RV pilot valve failed the As-Found testing low. Disassembly and testing was performed by NWS Technologies to determine cause. NWS concluded that the three-stage S/RV pilot was originally calibrated within the lower half of the acceptance range in the OEM specification. Calibration within the lower half of the acceptance range resulted in a greater setpoint drift, which ultimately resulted in the S/RV pilot being outside the allowable range.Page 3 of 4U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 0313112020 (04-2017)
RE 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
i.,
LICENSEE EVENT REPORT (LER) lessons learned are incorporated into the licensing process and fed back to industry. Sendcomments CONTINUATION SHEET regarding burden estimate to the FOIA, Privacy and Information Collections Branch (T-5 F53), U.S.
Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to lnfocolIects.Resourcenrc.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 0MB control number, the (See NUREG-1 022, R.3 for instruction and guidance for completing this form NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3/)
- 3. LER NUMBER YEAR SEQUENTIAL REV James A. FitzPatrick Nuclear Power Plant 05000
333 NUMBER NO.
2017 004 01 External Edwin I. Hatch Nuclear Plant, Unit 1: LER-16-004 Safety Relief Valves As Found Not Meeting Tech Spec Surveillance Criteria, May 26, 2016 Edwin I. Hatch Nuclear Plant, Unit 2: LER-08-004 Safety Relief Valves Allowable Exceeded Due to Setpoint Drift, August 12, 2008
Corrective Actions
Future Corrective Actions Commence replacement of S/RVs with redesigned three-stage (R023)
Previous Corrective Actions Installed Stellite 21 discs in all eleven S/RV pilot assemblies during refurbishment at the vendor facility Installed the S/RV Electric Lift System recommended by the Boiling Water Reactor Owners Group Installed enhanced insulation on the S/RVs
Safety Significance
Nuclear Safety Actual Consequences There were no actual consequences to the general safety of the public, nuclear safety, industrial safety, or radiological safety associated with this event.
Potential Consequences The potential consequences of this event are associated with the over-pressurization of the Reactor Coolant Pressure Boundary. The S/RVs provide overpressure protection for the Reactor Coolant Pressure Boundary as required by the ASME Boiler and Pressure Vessel Code. Events similar to the one reported herein may be significant if design limits are challenged. The potential consequences of this event are considered low based on the operation and availability of the Electric Lift System.
Radiological Safety There was no radiological safety impact associated with this event.
Industrial Safety There was no industrial safety impact associated with this event.
References Issue Report No. 04077124, R22 SRV As-Found Testing Failures Issue Report No. 04082823, R22 3-Stage SRV As-Found Testing Failure JAF Technical Specifications
Similar Events
Internal JAF LER-1 5-002 Safety Relief Valve JAF LER-1 1-003 Safety Relief Valve JAF LER-09-005 Safety Relief Valve JAF LER-07-001 Safety Relief Valve Upward Setpoint Drift, June 1, 2015 Setpoints Outside of Allowable Tolerances, Setpoints Outside of Allowable Tolerances, Setpoints Outside of Allowable Tolerances, August 8, 2011 June 22, 2009 August 6, 2007 Settings Resulted in Test RangePage 4 of 4