05000354/LER-2010-001
| Hope Creek Generating Station | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3542010001R01 - NRC Website | |
PLANT AND SYSTEM IDENTIFICATION
General Electric — Boiling Water Reactor (BWR/4) Safety Auxiliaries Cooling System (SACS)— EllS Identifier {CC}* Isolation Valve — EllS Identifier {ISV} Station Service Water System (SSW) — EEIS Identifier {BI}* *Energy Industry Identification System {El IS} codes and component function identifier codes appear as {SS/CCC}
IDENTIFICATION OF OCCURRENCE
Event Date: June 8, 2010 Discovery Date: June 8, 2010
CONDITIONS PRIOR TO OCCURRENCE
Hope Creek was in Operational Condition 1 at 100% core thermal power (CTP). No other structures, systems or components contributed to the event.
DESCRIPTION OF OCCURRENCE
On June 8, 2010, a review of the TS SR 4.7.1.1.b revealed that the SACS {CC} HX bypass valves (EG-HV 2457A/B {ISV} and EGTV-2517A/B {ISV}) may not have been adequately surveillance tested in accordance with the requirements of TS SR 4.7.1.1.b. A corrective action program notification (20466109) was written to document the concern. Due to the system configuration, these SACS HX Bypass valves were closed and declared inoperable while a review of design documents, procedures and.historical records was performed to determine whether or not these valves met the requirement to be included in the TS SR test population.
SR 4.7.1.1.b states that verification for SACS operability must be made "...at least once per 18 months by verifying that 1) Each automatic valve servicing safety-related equipment actuates to its correct position on the appropriate test signal(s)...".
The HCGS UFSAR (section 9.2.2.2) states "In the event of excessive temperature rise, the heat exchanger bypass valves are automatically closed to provide maximum cooling". Engineering calculations for SACS during design basis accidents assumes the bypass valves are closed to maintain SACS temperature less than 100 degrees F.
It has been determined that the 2457A/B and 2517A/B valves should be tested under SR 4.7.1.1.b.
Surveillance tests have been written and performed prior to restoring the EG-HV-2457A/B and EGTV 2517A/B valves to operation. An extent of condition review of other SACS valves is being performed.
The Hope Creek TSs were reviewed to determine if there are similar SRs in other systems. It was determined that there is only one other system with similarly worded surveillance Technical Specifications, the Station Service Water System (SSW) {BI} (SR 4.7.1.2.b.1). An extent of condition review of the automatic valves servicing safety related Service Water equipment is being performed.
� If additional valves are identified in the SACS and SSW system extent of condition reviews are identified as not being adequately included in the SR population, a supplement to this LER will be provided.
SAFETY CONSEQUENCES AND IMPLICATIONS
When the SR satisfaction was questioned for the 2457A/B valves and 2517A/B valves, both sets of valves were conservatively declared INOPERABLE and the valves were purposely failed closed, securing the HX
- bypass_flow. Engineering and Operations personnel reviewed plant data;design basis documents, surveillance tests, inservice test procedures and other data to determine if the 2457A/B and 2517A/B valves should be tested in accordance with TS SR 4.7.1.1.b, and/or if the existing testing performed on the 2457A/B and 2517A/B valves and associated circuitry was adequate to meet SR 4.7.1.1.b.
During the mid-to-late 1990s, Hope Creek Generating Station (HCGS) conducted a Technical Specification Surveillance Improvement Program (TSSIP) as a corrective action to LER 95-017. The TSSIP program reviewed TS SRs against existing procedures and processes to ensure compliance with the TS SRs. LERs were generated (95-035,95-034, 95-033 and supplements) to document areas where the SRs were not being met. Although LER 95-033-02 documented the SACS HX inlet valves as not being adequately tested for SR 4.7.1.1.b, no documentation could be located regarding the 2457A/B or the 2517A/B SACS HX bypass valves.
HCGS UFSAR section 9.2.2.2, SACS System Description, states "...the SACS loop coolant supply temperature is continuously monitored and controlled to the designed temperature range...In the event of excessive temperature rise, the heat exchanger bypass valves are automatically closed to provide maximum cooling...". Engineering calculations for the SACS during design basis accidents assumes the HX bypass line is isolated to maintain SACS temperature less than 100 degrees F.
A review of plant historical data from 07/01/2007 showed that the EG-HV-2457A and EG-HV-2457B valves each indicated closed whenever the SACS temperature in the respective loop rose to approximately 90 deg F. A sampling of the operating logs on dates that the valves indicated closed shows that the closures were automatic, and not manual, actuations. There were multiple closures each year for each valve. This provides a reasonable assurance that if the valves were called upon to respond to an accident condition, they would have fulfilled their design requirement by closing as the SACS temperature increased, and would be closed prior to SACS temperature reaching the design temperature of 100 deg. F.
A similar review for the EGTV-2517A/B valves was not possible due to lack of plant computer data points, but the past operability of the SACS system is assured due to the reasonable assurance of accident condition response by the EG-HV-2457A and EG-HV-2457B valves as discussed immediately above.
The inservice test program (IST) tests the closure of the 2457A/B valves using a local control switch. The 1ST program testing does not test the temperature trip function of the valves.
A review of this event determined that a Safety System Functional Failure (SSFF) did not occur as defined in Nuclear Energy Institute (NEI) 99-02.
CAUSE OF OCCURRENCE
The cause of this event was inadequate documentation and analysis of the surveillance procedures used to satisfy TS SR,4.7.1.1.b. The documentation and analysis occurred in the 1995 to,1997 timeframe during the TSSIP program that was instituted as a response to LER 95-017.
PREVIOUS OCCURRENCES
A review of Licensee Event Reports for the past three years at Hope Creek was performed to determine if a similar event had occurred. No similar events were noted.
CORRECTIVE ACTIONS
(1) Surveillance test procedures have been written to adequately test the EG-HV-2457A/B valves to the standard of TS SR 4.7.1.1.b.
(2) Surveillance test procedures have been written to adequately test the EGTV-2517A/B valves to the standard of TS SR 4.7.1.1.b.
(3) The surveillance test was successfully performed for the EG-HV-2457A/B valves prior to returning the valves to service.
(4) The surveillance test was successfully performed for the EGTV-2517A/B valves prior to returning the valves to service.
(5) An extent of condition review is being performed to validate the SACS automatic valves that service safety related equipment are included and tested to TS SR 4.7.1.1.b requirements.
(6) An extent of condition review is being performed to validate the SSW automatic valves that service safety related equipment are included and tested to TS SR 4.7.1.2.b.1 requirements.
COMMITMENTS
This LER contains no commitments.
FORM 366A (10-2010)