05000293/LER-2017-013

LER-2017-003, 1 OF 4

Pilgrim Nuclear Power Station
Event date:	11-26-2017
Report date:	01-25-2018
Reporting criterion:	10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident
2932017003R00 - NRC Website

LER 17-013-00 for Pilgrim Nuclear Power Station Regarding Reportable Conditions Involving Standby Gas Treatment System and Secondary Containment lnoperability Not Reported During the Previous Three Years

ML18033A326
Person / Time
Site:	Pilgrim
Issue date:	01/25/2018
From:	Miner P J Entergy Nuclear Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
2.18.001 LER 17-013-00
Download: ML18033A326 (7)

comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.

Pilgrim Nuclear Power Station 05000- 293 2017 - 00

BACKGROUND

The Pilgrim Nuclear Power Station (PNPS) Standby Gas Treatment System (SGTS) is part of the Secondary Containment System (SCS) and addresses the SGTS air filtration trains, including the ducting, the exhaust fans, the dampers, and the various filtration media. SCS is designed, in conjunction with other engineered safeguards and nuclear safety systems, to limit the release of radioactive material during normal plant operations within the limits of Title 10 Code of Federal Regulations (10 CFR) Part 20 and to limit the release of radioactive material so that off-site dose from a postulated design basis accident will be below the guideline values in 10 CFR Part 100.

The SGTS discharges processed gases to the Main Stack via underground piping. The Main Stack provides an elevated release point for the processed gases. The mission time for the SCS is 30 days.

PNPS Technical Specification (TS) 3/4.7.6.1 governs the operability requirements of the SGTS. The specification requires that with certain exceptions, the SGTS shall be operable during periods that include reactor power operation (RUN, STARTUP, and HOT SHUTDOWN modes), during movement of irradiated fuel assemblies in secondary containment, during movement of new fuel over the spent fuel pool, during CORE ALTERATIONS, and during operations with a potential for draining the reactor vessel (OPDRVs).

PNPS TS 3.7.C.1 requires secondary containment shall be OPERABLE when in the RUN, STARTUP, and HOT SHUTDOWN modes, during movement of recently irradiated fuel assemblies in the secondary containment, and during OPDRVs.

There are two principal accidents for which credit is taken for secondary containment operability. These are a loss of coolant accident and a fuel handling accident involving "recently irradiated fuel." The SCS performs no active function in response to each of these limiting events; however, its leak tightness is required to ensure that the release of radioactive materials from primary containment is restricted to those leakage paths and associated leakage rates assumed in the accident analysis and that fission products entrapped within the SCS will be treated by the SGTS prior to discharge to the environment.

EVENT DESCRIPTION

On November 26, 2017, with the Reactor in the Run Mode at 100 percent power, while reviewing procedures to be performed during a normal scheduled work week it was determined that if the procedure was performed as written would cause both trains of SGTS and SCS to be made inoperable. A follow up review determined that procedures have been performed several times within the past three years that caused both trains of SGTS and SCS to be made inoperable during scheduled testing of SGTS.

- 013 comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.

Pilgrim Nuclear Power Station 05000- 293 2017 - 00 This has been determined to be a reportable condition that has not been reported during the past three years involving the SGTS and SCS inoperability.

With both trains of SGTS and SCS inoperable in the Run mode this event is reportable per the requirements of 10 CFR 50.73(a)(2)(v)(C) and 10 CFR 50.73(a)(2)(v)(D), any event that could have prevented the fulfillment of the safety functions to control the release of radioactive material and mitigate the consequences of an accident.

A Root Cause Evaluation is underway and additional information will be provided at the conclusion of this ongoing investigation.

CAUSE OF THE EVENT

The direct cause of this event is still under investigation and will be provided in a supplement to this LER.

CORRECTIVE ACTIONS

An interim corrective action to place the identified procedures on administrative hold has been implemented.

SAFETY CONSEQUENCES

There were no consequences to the safety of the general public, nuclear safety, industrial safety, or radiological safety due to this event. The actual consequences were a loss of safety function for SCS and SGTS while performing the surveillance.

There was no adverse impact on the public health or safety.

REPORTABILITY

With both trains of SGTS and SCS inoperable in the Run mode, this event is reportable per the requirements of 10 CFR 50.73(a)(2)(v)(C) and 10 CFR 50.73(a)(2)(v)(D), any event or condition that could have prevented the fulfillment of the safety functions to control the release of radioactive material and mitigate the consequences of an accident.

- 013 comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555.0001, or by e-mail to NEOB-10202. (3150-0104), Office of Management and Budget. Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor. and a perbon is not required to respond to, the information collection.

Pilgrim Nuclear Power Station 05000- 293 2017 - 00

PREVIOUS EVENTS

A review was conducted of PNPS LERs issued in the past five (5) years. The review focused on LERs that involved similar events where the SGTS function was lost. This review identified similar events documented in:

1) LER 2017-004-00 "Secondary Containment Testing Led to Loss of Safety Function" 2) LER 2012-003-00 "Both Trains of Standby Gas Treatment System Inoperable"

REFERENCES

CR-PNP-2017-02900 CR-PNP-2017-11714 -013