Event Notification Report for March 30, 2017

LOSS OF ALL CONTROL ROOM ANNUNCIATORS

"The Unit 1 DC Cook Nuclear Plant (CNP) Annunciator System failed on Thursday, March 30, 2017 at 0255 [EDT]. The failure resulted in a complete loss of all alarm function of the Annunciator System in the Unit 1 Control Room. Unit 2 was unaffected by this failure. At 0310 [EDT], an Unusual Event (UE) was declared due to System Malfunction S-6, Loss of Alarms or Indication, due to an unplanned loss of safety system annunciators and/or indications in the Control Room for greater than 15 minutes.

"The Unit 1 PPC [Plant Process Computer] and ERDS [Emergency Response Data System] remain functional and available.

"This notification is being made in accordance with 10 CFR 50.72(a)(1)(i) due to the declaration of an Emergency Classification specified in the licensee's approved Emergency Plan."

The licensee has notified the NRC Resident Inspector, the State and local agencies.

Notified DHS SWO, FEMA Ops Center, DHS NICC. Notified FEMA National Watch and Nuclear SSA via E-mail.

* * * UPDATE FROM MAX MILLER TO DONG PARK AT 0821 EDT ON 3/30/2017 * * *

"Unit 1 DC Cook Nuclear Plant Annunciator System has been returned to functional. Unusual Event Classification was terminated at 0817 EDT on 3/30/17."

The NRC Resident Inspector will be notified.

Notified R3DO (Cameron), NRR EO (Miller), and IRD (Grant). Notified DHS SWO, FEMA Ops Center, DHS NICC. Notified FEMA National Watch and Nuclear SSA via E-mail.

UNANALYZED CONDITION DUE TO POTENTIAL TORNADO GENERATED MISSILES

"During the evaluation of tornado missile vulnerabilities and the potential impacts to safety-related plant equipment, it was concluded that the following structures are vulnerable to tornado generated missiles:

"All five of the Unit 1 and Unit 2 Emergency Diesel Generator (EDG) fuel oil storage tanks have ventilation pipe extending approximately 5 feet above grade. In the event that a tornado missile impact occurs on the aforementioned ventilation piping, there is a possibility that the vent lines could crimp. This could prevent the tanks from venting and inhibit the transfer of fuel oil from the main fuel oil storage tanks to the day tank. Ultimately, this causes the emergency diesels to be inoperable.

"These conditions are reportable per 10 CFR 50.72(b)(3)(ii)(B) and 10 CFR 50.72(b)(3)(v)(D) for any event or condition that results in the nuclear power plant being in an unanalyzed condition that significantly degrades plant safety and also an event or condition that could have prevented fulfillment of a safety function needed to mitigate the consequence of an accident. This issue is being addressed in accordance with EGM-15-002, Revision 1, Enforcement Discretion for Tornado-Generated Missile Protection Noncompliance.

"The NRC Resident Inspector has also been notified."

SECONDARY CONTAINMENT TECHNICAL SPECIFICATION NOT MET

"On March 30, 2017 at 1710 EDT, with Reactor Building HVAC in service maintaining normal building pressure, Reactor Building pressure began to rise for an unknown reason. The Technical Specification (TS) for secondary containment pressure boundary was not met for approximately 50 seconds. Division 1 Standby Gas Treatment System was started and returned Secondary Containment pressure to the TS operability limit of 0.125 inches of vacuum water gauge (TS SR 3.6.4.1.1). The highest pressure observed on the Main Control Room indications was 0.105 inches of vacuum water gauge. During the event, Operations with the Potential to Drain the Reactor Vessel (OPDRV) were in progress. Actions to immediately suspend OPDRVs were taken.

"Investigation of the cause of the event is in progress. There were no radiological releases associated with this event.

"Declaring secondary containment inoperable is reportable under 10 CFR 50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function needed to control the release of radioactive material.

"The licensee has notified the NRC Resident Inspector."

* * * RETRACTION AT 1652 EST ON 5/15/17 FROM JEFF YEAGER TO JEFF HERRERA * * *

"The purpose of this notification is to retract a previous report made on March 30, 2017 (EN 52651). The notification to the NRC involved an event where secondary containment momentarily exceeded the Technical Specification (TS) requirements during refueling activities which had been designated as operations with the potential to drain the reactor vessel (OPDRVs). The notification was made under 10 CFR 50.72(b)(3)(v)(C) as an 'event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to ... control the release of radioactive material.' Subsequent to the initial notification, the event and the NRC guidance in NUREG-1022 pertaining to 10 CFR 50.72(b)(3)(v) were reviewed further. At the time of the event, Fermi 2 was shutdown (Mode 5. Refueling). In Mode 5, the pressures and temperatures that could cause a loss of coolant accident (LOCA) are not present. No movement of fuel was in progress such that the fuel handling accident (FHA) was also not applicable. Thus secondary containment was only required per TS 3.6.4.1 due to the ongoing OPDRVs. The Fermi 2 UFSAR does not describe OPDRVs as an accident that secondary containment is required to mitigate. Based on this information, secondary containment was not required to mitigate the consequences of an accident as described in the UFSAR during the event on March 30, 2017. Under these circumstances, the momentary exceedance of TS requirements for secondary containment is not considered a loss of safety function under 10 CFR 50.72(b)(3)(v) per the guidance in NUREG-1022. Therefore, EN 52651 is retracted and no Licensee Event Report (LER) under 10 CFR 50.73(a)(2)(v) is required to be submitted."

The NRC Resident Inspector has been notified.

Notified the R3DO (Cameron).

OFFSITE NOTIFICATION DUE TO ONSITE FATALITY

"At 1630 PDT on March 30, 2017, a non-work related fatality occurred on the Diablo Canyon Power Plant property. The individual's work location was outside of the Protected Area. The fatality was not related to the health and safety of the public. Specifically, a contractor for Pacific Gas and Electric (PG&E) was found in the Security Training Building unresponsive. The individual was promptly attended to by Diablo Canyon personnel. The individual was subsequently pronounced dead by the San Luis Obispo County Paramedics.

"PG&E has not observed any heightened public, media, or government concerns as a result of the fatality. Because the fatality is unrelated to Diablo Canyon Power Plant industrial or radiological health and safety, no news release is planned.

"Because the fatality was not work related, nor the result of an accident, no notification to other government agencies was made at the time. However, PG&E will make a notification to the California Occupational Safety and Health Administration. Thus this ENS notification is in response to a notification to another government agency in accordance with 10 CFR 50.72(b)(2)(xi).

"The NRC Senior Resident Inspector and Resident Inspector have been notified."