05000528/LER-2005-002

LER-2005-002,

Docket Numbersequential Revmonth Day Year Year Month Day Yearnumber No.
Event date:	02-17-2005
Report date:	04-18-2005
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
5282005002R00 - NRC Website

1. REPORTING REQUIREMENT(S):

This LER 50-528/2005-002-00 is being reported under 10 CFR 50.73(a)(2)(i)(B), Operation or Condition Prohibited by the Technical Specifications. Specifically, on February 17, 2005 at approximately 17:52 hours MST Unit 1 entered a specified condition (reactor coolant system (RCS)(AB) pressure > 1837 psia) with a safety injection valve (1JSIBHVO307)(INV) not in its correct position. This is contrary to LCO 3.0.4 which precludes entry into a MODE or other specified condition in the Applicability statement when an LCO is not met. LCO 3.5.3 requires two Emergency Core Cooling Systems (ECCS)(BP) to be Operable in Modes 1, 2, and in Mode 3 when pressurizer (AB) pressure is greater than or equal to 1837 psia or RCS cold leg temperature is greater than or equal to 485 degrees Fahrenheit.

This condition also existed on February 19 at approximately 04:02 and 14:36 hours MST when Modes 2 and 1 were entered respectively.

COMPONENT(S):

The function of the ECCS is to provide core cooling and negative reactivity to ensure that the reactor core (AC) is protected after certain accidents. Two redundant, 100% capacity trains are provided with each train consisting of High Pressure Safety Injection (HPSI)(BQ) and Low Pressure Safety Injection (LPSI)(BP) subsystems including 1JSIBHVO307. In MODES 1, 2, and 3, with pressurizer pressure greater than or equal to 1837 psia or with RCS cold leg temperature greater than or equal to 485°F, both trains are required to be OPERABLE to ensure that 100% of the core cooling requirements can be provided in the event of a single active failure.

Valve 1JSIBHVO307 is a motor operated 10 inch stainless steel globe valve that is normally operated from the main control room. This valve is used to throttle shutdown cooling (SDC) heat exchanger bypass flow during shutdown operations and to provide a safety injection injection flow path for the LPSI pump during accident conditions. The normal at power position for this valve is a throttled open position with a limit switch used to limit the open travel. Full open indication for this valve is a red (open) light on, the green (closed) light off and the adjacent analog valve position indicator indicating the valve is in a throttled position. Verification of correct valve position is required following completion of valve stroking operation when the ECCS is required to be operable.

3. INITIAL PLANT CONDITIONS:

On February 17, 2005 at approximately 17:52 hours MST, Unit 1 was in Mode 3, Hot Standby, and increasing reactor coolant system temperature and pressure to return the unit to power operation following a forced shutdown due to an electrical bus event.

There were no components or systems inoperable at the time of this event that affected this event other than the condition being reported.

4. CHRONOLOGY OF RELEVANT EVENTS:

On February 10, 2005, Unit 1 was in the process of cooling down to Mode 5, Cold Shutdown, for a forced outage caused by an electrical bus problem. As part of the procedure for placing the B train shutdown cooling system in a standby alignment (The A train of SDC was the train used to provide SDC flow), the B train SDC heat exchanger bypass valve, 1JSIBHVO307, was throttled closed to approximately 20% open from its normal full open position indication of approximately 38% open.

On February 15, 2005, activities were in progress to return Unit 1 to power operation. As part of the recovery of SDC from a standby to a normal operating lineup procedure, operations personnel were directed to ensure that 1JSIBHVO307 was open. (Red light on, green light out) The B train SDC alignment was completed at 17:41 hours.

On February 17, 2005, at 17:52, hours the unit was in Mode 3 and reactor coolant system pressure was increased above 1837 psia. Subsequently the unit entered Mode 2, Startup, and Mode 1, Power Operation, on February 19, 2005 at 04:02 and 14:36 hours, respectively.

On February 21, 2005, at approximately 00:30 hours, operations personnel discovered that valve 1JSIBHVO307 was not in its correct position when a dual light indication at the valve breaker indicated the valve was not in its full throttled open position. Further investigation revealed that the green closed light for the main control room position indication was burned out. The analog valve position indication indicated the valve was approximately 20% open. Licensed operators entered LCO 3.5.3 Condition A then opened the valve to its throttle stop position. As required by the Technical Requirements Manual, a test was performed to verify the position of the valve and the LCO was exited at 02:44 hours on February 21, 2005.

5. ASSESSMENT OF SAFETY CONSEQUENCES:

A risk analysis of this event concluded that the total change in risk, due to valve 1JSIBHVO307 being out of position, constituted a very low addition to risk exposure. For this analysis the low pressure safety injection function was assumed to be failed for the B train of safety injection for the duration that the valve was not in its technical specification required position (80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br /> 52 minutes).

In addition, the event did not result in any challenges to the fission product barriers or result in the release of radioactive materials. The condition would not have prevented the fulfillment of any safety function and did not result in a safety system functional failure as defined by 10CFR50.73(a)(2)(v).

The event did not result in a transient more severe than those analyzed in the updated Final Safety Evaluation Report Chapters 6 and 15. The event did not have any nuclear safety consequences, personnel safety impact, or appreciable economic significance.

6. CAUSE OF THE EVENT:

The cause of this event is under investigation. If the completed investigation report includes information which would substantively change the reader's perception of the event, an LER supplement will be submitted. Preliminary investigation results indicate the cause of the event to be cognitive personnel error by two licensed operators.

First, the hand switch for valve 1JSIBHVO307 has a placard located near-by indicating that the operator should consult 40DP-90P07, Operations Department Operating Guideline Instructions. This procedure requires a technical specification component condition record (TSCCR) be initiated to alert licensed personnel that testing is required, to ensure the valve is in its correct position, when the valve has been operated. The TSCCR was not initiated for this valve when it was throttled to approximately 20% open during SDC standby line-up initiation operations. The operator assumed the test would be performed when the system was restored to a normal operating lineup.

Secondly, the recovery from SDC to normal operating lineup procedure (400P­ 9SI02) has a step to open SIB-HV-307 and a separate step to initiate performance of the valve position verification test (73ST-1X112). The operator verified the valve was open (based on light indication). He was not aware that the valve had been stroked to 20% open per the SDC initiation procedure (400P-95101). He therefore incorrectly concluded the valve had not been operated/stroked and that no testing would be required to verify valve position.

7. CORRECTIVE ACTIONS:

On February 21, 2005 at 00:30 hours, the burhed out bulb was replaced and valve 1JSIBHVO307 was placed in its full throttled open position. At 02:44 hours the surveillance test was completed verifying the valve was in its correct position.

The SDC initiation procedure, 400P-9S101, will be revised to require a TSCCR be initiated, when a SDC heat exchanger bypass valve is operated, to alert the operators to the requirement to perform the position verification test.

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8. PREVIOUS SIMILAR EVENTS:

occurred when required reactor power instrumentation was not calibrated as required by surveillance requirements. The cause of the event was human performance error by control room licensed operators who did not recognize the change in acceptance criteria when power was reduced below 80 percent.

percent rated thermal power without meeting the Limiting Condition for Operation (LCO) for Axial Shape Index (ASI). The cause was determined to be that control room operators had incorrectly interpreted a provisional note in procedures.

interpreted a provisional note in LCO 3.7.5 that allows Mode 3 operation with the steam driven AFW pump inoperable and proceeded with a mode change to Mode 3 on two separate occasions in violation of LCO 3:0.4. "—