ML16187A039

D. Lochbaum Email Pilgrim'S Inoperable EDGs

ML16187A039
Person / Time
Site:	Pilgrim
Issue date:	06/27/2016
From:	Lochbaum D Union of Concerned Scientists
To:	Diane Screnci, Neil Sheehan NRC Region 1
References
Download: ML16187A039 (1)

Text

ML16187A039 From: Dave Lochbaum [1]

Sent: Monday, June 27, 2016 9:02 AM To: Diane.Screnci@nrc.gov; Neil.sheehan@nrc.gov

Subject:

Pilgrim's inoperable EDGs Hello Diane and Neil:

By LER dated June 9, 2016 (attached), Entergy informed the NRC about both emergency diesel generators at Pilgrim being inoperable at the same time with the reactor operating at full power.

The LER stated that EDG B was removed from service for planned maintenance at 7pm on April 10, 2016.

More than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> later at 9:30 pm on April 11, 2016,, a worker noticed water leaking from the cooling water system for EDG A and running across the floor into the room's drain. EDG A was also declared inoperable, putting the plant into a condition where at least one EDG had to be returned to service within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or the reactor be shut down within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

Workers fixed the leak on EDG A and returned it to service at 10:59 am on April 12, 2016, or nesarly 40 hours4.62963e-4 days <br />0.0111 hours <br />6.613757e-5 weeks <br />1.522e-5 months <br /> after EDG B was removed from service.

Under the Corrective Actions section, the LER stated that fixes taken to prevent recurrence included "Procedure enhancement to inspect the opposite train EDG cabinets prior to performing scheduled maintenance on either EDG...".

This suggests that workers did not visually check EDG A before removing EDG B from service.

In that case, they did not verify that EDG A was likely to be operable before disabling its only backup.

How often do workers enter the room containing EDG A by procedure (e.g., once per 8-hour shift to record data on logs)?

Could the cooling water leak have been present before EDG B was removed from service?

If not likely, when is the last time it can be ascertained that EDG A was NOT leaking (i.e., when it was last known to be operable)?

If EDG A might have been leaking at the time workers took EDG B out of service, isn't it true that Pilgrim may have operated for longer than the maximum time permitted (24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> LCO plus 6 hour6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> shut down time) by the operating license?

Thanks, Dave Lochbaum UCS