05000272/LER-2003-001, Regarding Plant Operation for Greater than 72 Hours with 13 Auxiliary Feedwater (AFW) Pump Inoperable
| ML032110396 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 07/18/2003 |
| From: | Waldinger L Public Service Enterprise Group |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LR-N03-0304 LER 03-001-00 | |
| Download: ML032110396 (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)(B), Loss of Safety Function - Remove Residual Heat |
| 2722003001R00 - NRC Website | |
text
PSEG Nuclear LLC P.O. Box 236, Hancocks Bridge, New Jersey 08038-0236 LR-N03-0304 O PSEG Nuclear LLC JUL 1 8 2003 U. S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 LER 272/03-001-00 SALEM GENERATING STATION - UNIT I FACILITY OPERATING LICENSE NO. DPR-70 DOCKET NO. 50-272 This Licensee Event Report entitled "Plant Operation For Greater Than 72 Hours With 13 AFW Pump Inoperable" is being submitted pursuant to the requirements of 1 OCFR50.73(a)(2)(i)(B) and I OCFR50.73(a)(2)(v)(B)&(D).
L. Waldinger Director - Site Operations Attachment BJT C
Distribution LER File 3.7 95-2168 REV. 7199
I
Abstract
On May 23, 2003, during the performance of surveillance testing on the 13 Turbine Driven Auxiliary Feedwater (TDAFW) pump {BA/-}, the TDAFW pump tripped. During the start of the 13 TDAFW pump, the steam admission valve (MS132) valve popped open. The popping open of the 1MS132 valve caused an in-rush of steam and mechanical agitation (shaking and vibration) of the steam line. This mechanical agitation resulted in the unlatching of the steam trip valve (1 MS52) for the 13 TDAFW pump causing the pump to trip.
The cause of the 13 TDAFW pump trip is attributed to the popping open of the 1MS132 steam valve due to the split block being loose, which created a mechanical agitation of the steam line that led to the unlatching of the 1 MS52 trip valve. Corrective actions consist of the tightening of the split block for the 1 MS132 valve and satisfactory re-test of the valve, and changes to the maintenance procedure for the MS1 32 valves regarding the tightening of split blocks.
This report is being made in accordance with IOCFR50.73(a)(2)(i)(B), any operation or condition which was prohibited by the plant's Technical Specification' and 1 OCFR50.73(a)(2)(v)(B) & (D), any event or condition that could have prevented the fulfillment of the safety structures that are needed to: remove residual heat and mitigate the consequences of an accidents NRC FORM 366 (7-2001)U.S NUCLEAR REGULATORY COMMISSION (64m)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION DOCKET (2)
I FACILITY NAME (1)
NUMBER (2)
LER NUMBER (6)
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TEXT (If more space is required, use additional copies of NRC Form 366A) (17)
PLANT AND SYSTEM IDENTIFICATION
Westinghouse - Pressurized Water Reactor Auxiliary Feedwater System (BA-)
- Energy Industry Identification System {EIIS) codes and component function identifier codes appear as (SS/CCC)
CONDITIONS PRIOR TO OCCURRENCE Salem Unit I was in Mode I at 100% power at the time of discovery. No additional equipment was out of service that contributed to this event.
DESCRIPTION OF OCCURRENCE On May 23, 2003, during the performance of surveillance testing on the 13 Turbine Driven Auxiliary Feedwater (TDAFW) pump (BAI-), the TDAFW pump tripped. During the start of the 13 TDAFW pump, the steam admission valve (1 MS1 32) valve popped open. The popping open of the I MS1 32 valve caused an in-rush of steam and mechanical agitation (shaking and vibration) of the steam line.
This mechanical agitation resulted in the unlatching of the steam trip valve (1 MS52) for the 13 TDAFW pump causing the pump to trip. Prior to running the TDAFW pump for testing, the trip latch for the 1 MS52 trip valve is tested and re-latched. Operators involved in the latching of the I MS52 valve during this test state that the latch was properly reset.
The last time the 13 TDAFW pump was successfully run was on April 8, 2003. Since there is no evidence to determine the exact time that the 13 TDAFW pump was inoperable, it is being conservatively assumed that this pump has been inoperable for greater than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. In accordance with TS 3.7.1.2, action 'a' requires that, "with one auxiliary feedwater pump inoperable, restore the required auxiliary feedwater pumps to operable status with 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.-
This LER is being submitted pursuant to I OCFR50.73(a)(2)(i)(B) for many operation or condition which was prohibited by the plant's Technical Specifications," and I OCFR50.73(a)(2)(v)(B) & (D), any event or condition that could have prevented the fulfillment of the safety structures that are needed to:
remove residual heat and mitigate the consequences of an accident."U.S NUCLEAR REGULATORY CONMSSION (6-1998)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION DOCKET (2)
FACILITY NAME (1) fNUMBER (2).
LER NUMER (6)
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SALEM UNIT 1 05000272 03 0
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00 3 OF 4 TEXT (If more space is required, use additional copies of NRC Form 366A) (17)
CAUSE OF OCCURRENCE The cause of the 13 TDAFW pump trip is attributed to the popping open of the 1 MS1 32 steam valve due to the split block being loose, which created a mechanical agitation of the steam line that led to the unlatching of the I MS52 trip valve. The popping of the I MS132 valve appears to have been caused by the valve plug and cage binding during initial opening of valve. This binding only occurred when steam was applied to the valve. A steam vortex and pressure wave formed as the inrush of steam through the cage impacted the plug immediately after the pilot lifted. As a result, the valve plug and stem assembly could shift slightly to the side and be rotated if the valve stem is not properly restrained at the split block. The split block on the IMS 132 was found to be loose and required tightening. During the investigation of this event, it was determined that the maintenance procedure for Masonelian valve actuators does not provide any guidance regarding the tightening of the split block blot(s); thus, leaving the tightening of this connection to the skill-of-the-craft. Once properly tightened, the 1 MS1 32 valve operated smoothly and the pump was satisfactorily started.
PRIOR SIMILAR OCCURRENCES A review of LERs for Salem and Nope Creek for the previous two years did not Identify any similar occurrences of improper valve operation due to mechanical binding leading to the unavailability of safety related equipment.
SAFETY CONSEQUENCES
A review of operations logs identified five instances of removal of one of the two Motor-Driven AFW (MDAFW) pumps from service during the period between April 8 and May 23. With the 13 TDAFW pump inoperable, removing one of the MDAFW pumps from service only leaves one MDAFW pump to respond to an event. In accordance with Salem UFSAR Sections 15.2.8, Loss of Normal Feedwater," and 15.2.9, "Loss of Offsite Power to the Station Auxiliaries," these analyses assume that the auxiliary feedwater system will deliver 700 gpm of flow to the steam generators. One MDAFW pump is only capable of delivering 440 gpm, which is insufficient auxiliary feedwater flow to meet the assumptions of the analyses. Although, only one MDAFW pump would be available at the start of the event, emergency operating procedures direct the operators to restore the TDAFW pump to service if it failed to start. Guidance to perform the restoration of the TDAFW pump is contained in plant operating procedures. Upon restoration of the TDAFW pump, more than sufficient AFW flow would be available to mitigate these events. Following the trip of the 13 AFW pump, a review of procedures and a walkdown of the 13 TDAFW pump by operators determined that the pump could have been readily restarted.Us. NUCLEAR REGULATORY COMMISSION (6-1998)
LICENSEE EVENT REPORT (LER)
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00 4 OF 4 SAFETY CONSEQUENCES (contd)
During the period of April 8 to May 23, 2003, there were no actual events that required the operation of the AFW system. Salem Unit I continued to operate In Mode I during this entire period. Therefore there were no actual safety consequences associated with this event.
A review of this event determined that this condition was a Safety System Functional Failure (SSFF) as defined in Nuclear Energy Institute (NEI) 99-02.
CORRECTIVE ACTIONS
- 1. Tightened the split block for the 1MS132 steam admission valve and satisfactorily re-tested the valve.
- 2. Procedure SH.IC-GP.ZZ-0002(Q), Disassembly, Inspection, Reassembly and Testing of Masoneilan Model 37/38 Air Operated Actuators', is being revised to include instructions for tightening split blocks.
- 3. A walkdown of other safety related valves that utilize the split block connection was performed at both Salem and Hope Creek to ensure that the split blocks on these valves were not loose. In addition, the Salem Unit 2 2MS132 valve for the 23 TDAFW pump was verified to be at the correct torque value.
The above actions are being tracked in accordance with PSEG Nuclears corrective action program.
COMMITMENTS
The corrective actions cited in this LER are voluntary enhancements and do not constitute
commitments