05000281/LER-2002-004

LER-2002-004,

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
2812002004R00 - NRC Website

FACILITY NAME (1)

DOCKET

05000 - 281 05000 - LER NUMBER 6) PAGE (3) 2 o of 4 1.0 DESCRIPTION OF THE EVENT At 1815 hours0.021 days <br />0.504 hours <br />0.003 weeks <br />6.906075e-4 months <br /> on November 23, 2002 with Unit 2 at Hot Shutdown conditions, post-maintenance testing (PMT) was initiated on main steam stop valves #1 and #3 following valve limit switch adjustments. As part of the PMT, fuses FUDC-5 and FUDC-6 in the turbine solenoid trip circuit, as well as fuses FUDC2-1, and FUDC2-2 in the backup turbine solenoid trip circuit, were removed. With these fuses removed, Trains A and B of the turbine trip logic were defeated.

Technical Specification (TS) Table 3.7-1 Functional Unit 11 requires Turbine Trip instrumentation to be operable above the P-7 permissive (10% power); since the plant was at Hot Shutdown conditions, this requirement was not applicable. However, TS Table 3.7-3 Functional Unit 3.b requires a minimum of two operable channels of automatic actuation logic and actuation relay for Turbine Trip and Feedwater Isolation.

Associated TS Table 3.7-3 Operator Action 22 permits one less than the minimum channels to be inoperable for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or be in at least Hot Shutdown within the next six hours and reduce Reactor Coolant System (RCS) temperature and pressure to less than 350 degrees F and 450 psig within the following 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. With the plant conditions above 350 degrees F and 450 psig and with both trains of the turbine trip logic defeated, a condition prohibited by TSs existed and is being reported in accordance with 10CFR50.73(a)(2)(i)(B).

2.0 SIGNIFICANT SAFETY CONSEQUENCES AND IMPLICATIONS A required initial condition of the procedure being used to perform the PMT on main steam stop valves #1 and #3 is to verify that the main steam trip valves and trip valve bypass valves are closed. Therefore, steam flow to the turbine was isolated; however, with the turbine trip fuses removed, Trains A and B of the turbine trip logic were defeated.

The feedwater isolation portion of the circuit was not affected by the fuses being removed and remained operable.

The primary functions of the Turbine Trip and Feedwater Isolation required by TS Table 3.7-3 are to prevent excessive flow of feedwater into the steam generators and excessive RCS cooldown, as well as to prevent carryover of water into the steam lines and turbine. With Feedwater Isolation operable, feedwater flow to the SGs would have been isolated if required. With the main steam trip valves and trip valve bypass valves closed, isolation of the flow path to the turbine had been accomplished, effectively fulfilling the required function of the Turbine Trip.

Since the functions of the Turbine Trip and Feedwater Isolation signals were either effectively completed or could have been achieved if required, there were no significant safety consequences or implications associated with this event.

3.0 CAUSE The history of the procedure used to perform the PMT on the main steam stop valves was researched. A 1997 procedure revision added steps to remove the fuses for the turbine trip solenoids to latch the turbine in order to permit valve testing with the plant shut down.

A restriction to be below 10% power (P7 permissive) was identified as a limiting condition of the supporting safety evaluation. This restriction of less than 10% power (from TS Table 3.7-1) was included as an initial condition in the procedure revision. However, it is now recognized that a human error resulted in TS Table 3.7-3 being overlooked and not being considered in the preparation of the 1997 procedure revision and its supporting safety evaluation, both of which were prepared by licensee personnel. Thus, the 1997 procedure revision allowed a condition to exist that was not consistent with the requirements of TS Table 3.7-3 Functional Unit 3.b.

4.0 IMMEDIATE CORRECTIVE ACTION(S) During this evolution, a review of the procedure for the PMT was conducted by the on-shift Assistant Shift Supervisor, and it was determined that both trains of Turbine Trip were defeated while the fuses were removed. A Plant Issue/Deviation documenting the circumstances was issued.

5.0 ADDITIONAL CORRECTIVE ACTIONS An action associated with the Plant Issue/Deviation requested further review by the Operations Department to determine required actions. This review concluded that procedural changes are required to correct the oversight that occurred in the 1997 time frame. Procedure revisions have been initiated, and completion of the revisions is being tracked in the Corrective Action System.

6.0 ACTIONS TO PREVENT RECURRENCE The individuals involved will be coached, and the expectation to perform thorough and proper reviews will be reaffirmed.

7.0 SIMILAR EVENTS 1. LER 1/2-1998-003-00, titled No Procedural Guidance for Maintaining EDG Minimum Fuel Supply During LOOP, documented that the circumstances resulted from an oversight in the development of the original plant operating and emergency procedures.

2. LER 1-1999-001-00, titled Auxiliary Feedwater Pipe Support Missed Surveillance Due to Personnel Error, documented that the circumstances resulted from two supports being Inadvertently omitted from the ISI inspection drawings.

8.0 MANUFACTURER/MODEL NUMBER Not applicable.

9.0 ADDITIONAL INFORMATION Unit 1 was operating at 100% power at the time of this event.