05000423/LER-2001-002
| Event date: | 05-09-1999 |
|---|---|
| Report date: | 06-18-2001 |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(i) |
| 4232001002R01 - NRC Website | |
1. Event Description On February 7, 2001, a concern was raised regarding compliance with Millstone Unit No. 3 (MP3) TS 4.6.3.1 requirements for post-maintenance testing on CIVs. A historical review was initiated and on February 15, 2001 it was identified that adequate post-maintenance testing had not been performed in accordance with TS 4.6.3.1 (isolation time test) for CIV 3CCP*MOV45A, a Millstone Unit No. 3 (MP3) reactor plant component cooling water [CC] supply header isolation [ISV] valve. Given the historical nature of this condition and the fact that current OPERABILITY had been verified for all MP3 CIVs, the historical review for MP3 was concluded. At the time of the event, the unit was in Mode 5.
On February 15, 2001, it was determined that incomplete post-maintenance testing had been performed for maintenance activities which occurred on May 5, 1999 for 3CCP*MOV45A. This valve, which also functions as a Containment Isolation Valve (CIV), did not receive a post-maintenance isolation time test as required by MP3 Technical Specification (TS) 4.6.3.1.
On February 23, 2001, during the investigation of the extent of condition for the MP3 event, it was determined that a Millstone Unit No. 2 (MP2) CIV also did not receive adequate post-maintenance testing as required by TSs. This CIV, a Steam Generator Blowdown [WI] Control Valve (2-MS-220A) [FCV], also did not receive a post- maintenance isolation time test as required by MP2 TS 4.6.3.1.1.b. after maintenance activities which were completed on July 16, 1999 while Millstone Unit No. 2 was in Mode 1 at approximately 100% power.
MP3 TS 3.6.3, "Containment Isolation Valves," Surveillance Requirement (SR) 4.6.3.1 and MP2 TS 3.6.3.1, "Containment Isolation Valves," SR 4.6.3.1.1.b both require in Modes 1, 2, 3 and 4 that each isolation valve be demonstrated operable prior to returning the valve from service after maintenance, repair, or replacement work is performed on the valve or its associated actuator, control, or power circuit [JX] by performance of a cycling test and verification of isolation time.
MP3 CIV 3CCP*MOV45A was identified as not receiving a required post-maintenance test following maintenance activities which were performed on May 5, 1999 during a MP3 refueling outage. This CIV was cycled after Motor [MO] Control Center (MCC) breaker [BKR] preventative maintenance had been completed, but an isolation time test was not performed prior to entry into Mode 4 (June 24, 1999) and reactor startup. For the MP2 CIV (2-MS- 220A) an isolation time test was not performed after a packing adjustment was performed on the CIV. For both the MP2 CIV and the MP3 CIVs it was not identified in the post-maintenance testing documentation that the applicable TS required verification and documentation of each valve's isolation time.
Therefore, both the MP2 and MP3 events are being reported in accordance with 10 CFR 50.73(a)(2)(i)(B), any operation or condition prohibited by the plant's Technical Specifications.
In the initial issuance of this Licensee Event Report three MP3 CIVs (3MSS*MOV74B, 3MSS*MOV74D, and 3RSS*MOV23B) had been reported as violations of TS SR 4.6.3.1. However, upon further review of these events it was determined that these three valves do not change state (normally maintained in their accident analysis position) during accident conditions. Therefore, the requirements of TS 4.6.3.1 for an isolation time test do not apply to these three valves.
2. Cause The cause of this event was an incomplete component database used in identifying post-maintenance testing requirements for CIVs. The facility component database does not list all Technical Specification post-maintenance testing for equipment governed by Technical Specifications.
3. Assessment of Safety Consequences Validating primary containment integrity ensures that the release of radioactive materials from the containment atmosphere will be restricted to those leakage paths and associated leak rates assumed in the accident analyses.
This restriction, in conjunction with the leakage rate limitation, will limit the site boundary radiation doses to within the limits of 10 CFR 100 during accident conditions.
Retest of the MP3 CIV (3CCP*MOV45A) and the MP2 CIV (2-MS-220A) indicates that each CIV would have closed within the required time to satisfy accident analysis assumptions, indicating that each valve was capable of performing its required safety function. Therefore, these events were not safety significant.
4. Corrective Action As a result of these events, the following actions have been, or will be, performed.
1. Isolation time testing was performed and verified acceptable for the identified MP2 and MP3 Containment Isolation Valves.
2. Interim guidance on the requirements of TS 4.6.3.1 for MP3 and TS 4.6.3.1.1.b for MP2 was given to individuals involved in processing work orders for stroke time testing of Containment Isolation Valves.
3. The component database utilized for work planning will be upgraded to include additional information on TS CIV test requirements for post-maintenance activities.
An investigation was conducted and corrective actions are being addressed in accordance with the Millstone Corrective Action Program.
5. Previous Occurrences results, it was determined that inadequate post-maintenance testing had been performed on a Pressurizer Relief Line Flow Control Sample Air Operated Valve (AOV). By replacing the valve operator air supply solenoid, which is an auxiliary to the parent AOV (2-RC-003), the valve closing stroke time performance characteristics were affected, necessitating a retest of the valve stroke time in accordance with the facility Technical Specification Surveillance Requirements. A retest of the valve stroke time was not performed in a timely manner. The cause of this event was an inadequate man-machine interface and a lack of training on post-maintenance test requirements which led to the development of a deficient work package. To correct this deficiency training was performed on both identification of post-maintenance test requirements and on expectations for review and approval of work package post-maintenance test requirements. Additionally, upgrades to the facility electronic database system were planned to help ensure the work order development process reflects quality controlled program indicators.
Energy Industry Identification System (EIIS) codes are identified in the text as [XX].