Event Notification Report for June 11, 2008

HPCS DECLARED INOPERABLE

"This report is being made pursuant to 10CFR50.72(b)(3)(v)(D), Event or condition that could have prevented fulfillment of a safety function needed to mitigate the consequences of an accident. During steady state operations, a Division 3 AC ground alarm was received, followed by a trip of the 2VD05C Division 3 switchgear room / Core Standby Cooling System (CSCS) Pump Room Supply Fan. Division 3 supplies power to the High Pressure [Core Spray] (HPCS), which is a single-train system. Although the system remained functional and capable of vessel injection following the failure, the HPCS system and its associated power supplies were declared inoperable based on long-term temperature considerations. At 1703, the circuit breaker for the HPCS injection valve, which is a Primary Containment Isolation Valve (PCIV), was opened and the valve deenergized in the closed position to comply with Technical Specifications. Disabling the injection valve affects the safety function of the system (HPCS), and this is reportable as an 8-hour ENS notification.

"The cause of the ventilation fan motor trip has been determined to be a motor fault. Replacement of the fan motor is in progress."

This event places the plant in a 14-day LCO per Technical Specification 3.5.1. Repairs are expected to be completed by 0700 on 6/12/08. The Reactor Core Isolation Cooling (RCIC) system is operable.

The licensee notified the NRC Resident Inspector.

AGREEMENT STATE REPORT - RECOVERED NUCLEAR MATERIAL

The state provided this information via e-mail:

"It was reported today by [Pennsylvania Department of Radiation Protection] staff, that an orphan radioactive source was found in a lot of equipment and materials that had been acquired years prior from a bankrupt firm. The source is in Lake City, PA, and was inspected today for radionuclide identification, external exposure rates, and possible leakage. The source is in storage and appears to be in a shielded configuration (~ 3 mR/h contact with the device; background outside the storage area), no leakage was detected. [The source is contained in an industrial density gauge.] Information is still being gathered, but it apparently has been in storage for years. It was identified as a Cesium-137 source, activity noted as 100 millicuries (mCi) in 1979, thus, with a 30 year half-life, is now about 50 mCi. BRP is working with the owner and external agencies and organizations (i.e., NRC, DOE and CRCPD) to ensure the source remains secure, and, proper transfer and/or disposal is performed in a timely manner. There are also some records of prior ownership available, which may possibly assist in cost recovery with this abandoned 'generally licensed' (GL) source. An initial NRC 'NMED report' will be filed shortly. "

* * * UPDATE AT 1730EDT ON 06/13/08 FROM D. ALLARD TO NRC OPS CENTER VIA EMAIL * * *

The state provided this information via e-mail:

"Working with CRCPD, a health physics service provider was hired to take the Oakes Machine Corp density gauge. The cabinet was opened and a KayRay Model 7062P, Cs-137 source housing was found; serial # 7825. It contained an original activity of 100 mCi (May1978). CRCPD has arranged for transfer to another licensed firm, who will recycle or dispose of the source. BRP will submit a NMED report to NRC."

Notified R1DO (Summers) and FSME (Mauer).

IDENTIFICATION OF A POTENTIAL ISSUE WITH ACCUMULATOR DRAIN VALVES

"On June 11, 2008 at 1405 PDT, licensed plant operators entered Technical Specification (TS) 3.0.3 on Units 1 and 2 due to identification of a potential ASCO solenoid valve failure that could initiate draining if the safety injection system accumulators following a small break Loss-of-Coolant-Accident (LOCA).

"ASCO Model 8316 and 8321 pilot-operated solenoid valves over 12 years old are susceptible to a potential shuttle ('insert' per vendor documentation) malfunction. The malfunction is that with greater than 12 years of service and a loss of minimum operating pressure differential (MPOD), the shuttle (or insert) could reposition and fail to return to the desired position. This MPOD related reposition could result following instrument air pressure loss and subsequent restoration to containment following a postulated small break LOCA. Diablo Canyon Power Plant (DCPP) Units 1 and 2 each have four susceptible ASCO solenoid valve locations used as drain valves for each of the four safety injection system accumulators per unit.

"DCPP is reviewing the performance of the ASCO solenoids based on a plant problem report and subsequent discussion with the vendor. The safety significance of this event is low as there was no actual accumulator drain valve failure. Although PG&E is still evaluating the potential degradation mechanism and failure mode of these valves, TS 3.03 was conservatively entered base on the potential for malfunction of these valves.

"On June 11, 2008, at 1610 PDT licensed plant operators exited TS 3.0.3 following isolation of the suspect accumulator drain lines. A licensee event report will be issued for this event.

"The NRC Resident Inspector has been notified."