05000362/LER-2004-002, Regarding Incomplete Postmaintenance Calibration of Logarithmic Power Level-High Channel a Results in Technical Specification Violations
| ML042300429 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 08/09/2004 |
| From: | Waldo R Southern California Edison Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LER 04-002-00 | |
| Download: ML042300429 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3622004002R00 - NRC Website | |
text
-
ar i
V1 SOUTHERN CALIFORNIA EDISONI An EDISON INTERNATIONVAL Company Dr. Raymond W. Waldo Station Manager San Onofrc August 9, 2004 U.S. Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555-0001
Subject:
Docket Nos. 50-362 Licensee Event Report No. 2004-002 San Onofre Nuclear Generating Station, Unit 3 Gentlemen:
This submittal provides Licensee Event Report (LER) 2004-002 for an incomplete post-maintenance calibration of Logarithmic Power Level-High Channel UA' which resulted in Technical Specification Violations.
Any actions listed are intended to ensure continued compliance with existing commitments as discussed in applicable licensing documents; this LER contains no new
commitments
If you require any additional information, please so advise.
Sincerely, LER No. 3-2004-002 cc:
B. S. Mallett, NRC Regional Administrator, Region IV C. C. Osterholtz, NRC Senior Resident Inspector, San Onofre Units 2 & 3 P.O. Box 128 San Clemente, CA 92672-0128 949-368-8725/PAX 88725 Fax 949-368-6183 waldorwasongs.sce.comr
1,
Abstract
During a recent plant outage, SCE repaired Channel *A' of Log Power by replacing a discriminator card and calibrating the channel. Channel "A' was placed in-service for the plant startup that was completed on 61612004. On 618/2004, plant personnel were reviewing calibration records and noticed that one portion of the calibration procedure had not been completed. Completing a startup without a valid calibration for Log Power Channel WAN violated TS 3.3.1, TS 3.3.2, and TS 3.0.4.
This event resulted from a misunderstanding of the actions necessary and sufficient to restore Channel *A7 to Operable status (individual personnel error). When performing the calibration, one step of the calibration procedure could not be completed as required. The individuals involved thought the step was not needed to restore Operability and closed the MO as ucomplete.' Closing the MO caused the Control room to believe that channel 'A' had been returned to Operability.
SCE has counseled/coached the individuals involved as appropriate. Additional corrective actions are under consideration.
This event had no safety significance because Log Power Channels WB, OC', and ND" were unaffected by this occurrence and were fully Operable.U.S. NUCLEAR REGULATORY COMMISSION (7-200t)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUAllON
- 1. FACILTY NAME
. DOCOWT NUMBER I.
UR NUMBER PACE 13_
San Onofre Nuclear Generating Station (SONGS) Unit 3 05000-362 lYAR 2004L R
NO 2 of 3 Plant:
San Onofre Nuclear Generating Station (SONGS) Unit 3 Event Date:
June 6, 2004 Discovery Date:
June 8, 2004 Reactor Vendor Combustion Engineering Mode:
Mode 3 - Hot Standby Power 0 percent
Background
SONGS Unit 3 Reactor Protection System (RPS) [JC] includes four channels ("A' through 'D") of Logarithmic Power Level-High trip (Log Power) to protect against an unplanned criticality from a shutdown condition. A reactor trip is initiated by the Logarithmic Power Level-High trip at a less than or equal to 0.93 percent of Rated Thermal Power (RTP) unless this trip is bypassed by the operator. The bypass is automatically removed when the logarithmic power level decreases below 1 E-4 percent of RTP.
Technical Specification (TS) 3.3.1, RPS Instrumentation-Operating, and TS 3.3.2, RPS Instrumentation-Shutdown, together require four Log Power and Operating Bypass Removal channels to be Operable in Modes 2, 3, 4, and 5 when any reactor trip circuit breaker (RTCB) [BKR] is closed and any control element assembly is capable of being withdrawn. If one channel of Log Power becomes inoperable in Modes 2, 3, 4, or 5, these TSs require the inoperable channel to be placed in bypass within one hour and to be returned to Operable status prior to entering Mode 2 following the next entry into Mode 5.
On January 26, 2004, Action Request 040101660 was written when Unit 3 Log Power Channel 'A failed a TS surveillance because it was reading about one decade lower than the other three channels. Operators bypassed this channel until no longer required by TS 3.3.2, RPS Instrumentation-Shutdown, and TS 3.3.1, RPS Instrumentation-Operating.
On June 4, 2004, at 0445 PDT, plant operators manually tripped the Unit 3 reactor due to degraded circulating water pump [P] suction caused by heavy influx of sea grass across the traveling screens [SCN] during very low tide conditions. Unit 3 remained in Mode 3 until it was returned to full power operation about two days later. That event was reported to the NRC in LER 3-2004-001.
Description of the Event Although not required by the TS, SCE used the June 4, 2004 outage as an opportunity to repair Log Power Channel OA.' Plant technicians (utility, non-licensed) replaced a discriminator card and performed the TS-required channel calibration procedure. Control Room (utility, licensed) personnel returned the channel to Operable status at 2305 PST on June 5, 2004 and then proceeded with an orderly plant startup. Unit 3 entered Mode 2 at 0023 PST on June 6, 2004 and Mode 1 at 0317 PST on the same date.
On June 8, 2004 (discovery date), plant personnel (utility, non-licensed) reviewing Log Power channel OA" maintenance records noticed a conflict between the 'work done' section of the maintenance order (MO) and the steps signed as
'complete' in the calibration procedure. After investigating the conflicting information, it was determined that part of the calibration procedure was not performed in accordance with the procedural requirements. Control Room personnel were informed and declared this channel inoperable.
Completing a plant startup without placing a TS-inoperable Log Power Channel in bypass within one hour resulted in the following TS violations:
IU.S. NUCLEAR REGULATORY COMMISSION (7-201)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION
- 1. FACLITY NAME 2 DOCKET NMBER I.
LER NUMBER PAGE p3 Yan NoSEQUENTIAL San Onofre Nuclear Generating Station (SONGS) Unit 3 05000-362 j
- 1~
WNSER
_3 of3 12004 1-002-0
- 1. TS 3.3.2 requires four channels of Log Power to be Operable whenever the plant is in Modes 3, 4, or 5 and with one or more reactor trip circuit breakers (RTCB) closed and any control element assembly capable of being withdrawn. Action "A7 requires an Inoperable channel of Log Power to be placed in bypass within one hour, which was not done.
- 2. TS 3.3.1 requires four channels of Log Power to be Operable when any RTCB is closed. Action OX requires an inoperable channel of Log Power to be placed in bypass within one hour, which was not done.
- 3. TS 3.0.4 requires an LCO to be met prior to entry into a Mode or other condition specified in the LCO applicability statement. TS 3.0.4 was not met because operators changed plant Mode without having Log Power Channel WA in bypass.
SCE is providing this report in accordance with 10 CFR 50.73(a)(2)(i)(B).
Cause of the event
This event resulted from a misunderstanding of the actions necessary and sufficient to restore Channel OX to Operable status (individual personnel error). When performing the calibration, part of the calibration procedure was not completed as required. The individuals involved thought the step was not needed to restore Operability and closed the MO as 0complete." Closing the MO caused the Control Room to believe that channel OA had been returned to Operability.
Corrective Actions
SCE has counseled/coached the individuals as appropriate. Additional corrective actions are under consideration.
Safety Significance
This event had no safety significance. Log Power Instrumentaton Channels 'B, MCO, and D" were unaffected by this occurrence and were fully Operable. As noted in the background section of this report, the TS allows continued operation with one channel of Log Power in bypass.
Additional Information
In the past three years, SCE has not reported any other occurrences placing an RPS channel in service with an incomplete TS calibration.