05000255/LER-2002-001

LER-2002-001, NONCOMPLIANCE WITH TECHNICAL SPECIFICATION REQUIREMENTS FOR SAFETY INJECTION TANK T-82D

Docket Number
Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
2552002001R00 - NRC Website

EVENT DESCRIPTION

On November 11, 2002, at approximately 1339 hours0.0155 days <br />0.372 hours <br />0.00221 weeks <br />5.094895e-4 months <br />, with the plant operating at 100% power, operations noted apparent leakage from safety injection tank T-82D [UK; BP] via trending of multiple plant parameters. Subsequently, safety injection tank T-82D and associated piping were visually inspected for evidence of leakage. During this inspection, leakage was visually observed from the 3/4" piping side of the sock-o-let attaching the lower sensing line for level transmitter LT-0374 [LT; BP] to the main 12" downcomer from safety injection tank T-82D. This joint leak was non-isolable from safety injection tank T-82D. Safety injection tank T-82D was declared inoperable at 1345 hours0.0156 days <br />0.374 hours <br />0.00222 weeks <br />5.117725e-4 months <br /> on November 11, 2002, and Condition B of Technical Specification 3.5.1 was entered.

Palisades Technical Specification 3.5.1, "Safety Injection Tanks," requires four safety injection tanks to be operable in Modes 1 and 2. Condition B of Technical Specification 3.5.1 requires an inoperable safety injection tank be restored to operable status within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. In the event that the required action and associated completion time of Condition B are not met, Condition C provides further required actions to be in Mode 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

Nuclear Management Company, LLC requested enforcement discretion to extend the completion time for Technical Specification 3.5.1, Condition B, by 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, for a total of 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />, to allow for restoration of safety injection tank T-82D to operable status. The Nuclear Regulatory Commission verbally exercised discretion at 1332 hours0.0154 days <br />0.37 hours <br />0.0022 weeks <br />5.06826e-4 months <br /> on November 12, 2002. Nuclear Management Company reduced plant power to approximately 60% and performed the required repairs to safety injection tank T-82D, which was subsequently declared operable at 0906 on November 13, 2002.

This occurrence is reportable in accordance with 10 CFR 50.73(a)(2)(i)(B) as a condition prohibited by Technical Specifications, since safety injection tank T-82D was not restored to operable status within the 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> allowed by Technical Specification 3.5.1, Condition B.

CAUSE OF THE EVENT

The action completion time of Technical Specification 3.5.1, Condition B was knowingly exceeded under an approved Notice of Enforcement Discretion.

SAFETY SIGNIFICANCE

Extension of the allowed outage time was evaluated from a probabilistic risk standpoint. The risk associated with maintaining the reactor at power for an additional 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> with safety injection tank T-82D inoperable was determined to be lower than the risk associated with performing a reactor shutdown.

CORRECTIVE ACTIONS

Required repairs were made to restore safety injection tank T-82D to operable status.

A license amendment was not required because the plant was returned to compliance with the existing license in a short period of time.

PREVIOUS SIMILAR EVENTS

The root cause of the safety injection tank T-82D level-sensing line joint failure was determined to be high-cycle fatigue. The same joint failed in 1992. The root cause was believed to be a manufacturing defect. However, re-examination of the previous failure, along with the information from the recent failure, indicates that the failure mechanism for both failures was high-cycle fatigue.

PREVIOUS LERs None