PNO-IV-03-054, Response to California Earthquake
| ML033570309 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 12/23/2003 |
| From: | William Jones NRC Region 4 |
| To: | |
| References | |
| PNO-IV-03-054 | |
| Download: ML033570309 (1) | |
December 23, 2003 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE -- PNO-IV-03-054 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information is as initially received without verification or evaluation, and is basically all that is known by the Region IV staff on this date.
Facility Pacific Gas and Electric Company Diablo Canyon Power Plant Units 1 and 2 Avila Beach, California 93424 Dockets: 50-275; 50-323 License Nos. DPR-80; DPR-82 Licensee Emergency Classification X Notification of Unusual Event Alert Site Area Emergency General Emergency Not Applicable
SUBJECT:
RESPONSE TO CALIFORNIA EARTHQUAKE DESCRIPTION:
On December 22, 2003, at 11:16 a.m. PST, a magnitude 6.5 earthquake occurred approximately 35 miles northwest of Diablo Canyon Power Plant. The licensee declared a notification of unusual event (NOUE) at 11:22 a.m. PST for the ground motion felt by the control room operators and measuring greater than 0.01g acceleration (0.04g was recorded on the Earthquake Force Monitor in the control room). Diablo Canyon Power Plant Units 1 and 2 remained at 100 percent power following the earthquake. The licensee performed walkdowns of the fire protection systems, both containment buildings, auxiliary buildings, the turbine building, and other areas. Additionally, walkdowns of the offsite power lines were conducted. No structural damage was identified during these walkdown activties. The 230kv offsite power supply was impacted by 2 failed switches at the Morro Bay switchyard, but offsite power was still available to Diablo Canyon Power Plant. The failed switches have been repaired by the licensee. Emergency evacuation routes remained available throughout the emergency planning zone although, Highways 41 and 46 did have some debris and buckling of the roadways. Fifty-six of the 131 emergency sirens were unavailable immediately following the earthquake, with nine emergency sirens within the emergency planning zone being unavailable because of a loss of power. All sirens, except for 3 located outside the emergency planning zone, have been returned to service as of 7 a.m. PST on December 23.
The licensee decided to remain in the NOUE for a minimum of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> based on aftershocks that have occurred and notification from the United States Geological Survey of probable aftershocks for the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following the initial earthquake. The resident inspectors responded to the control room at the time of the earthquake, independently monitored the plant response to the earthquake, and walked down plant equipment. A resident inspector has remained onsite since the earthquake and will continue to remain on site throughout the period the licensee remains in the NOUE.
The state of California has been informed.
The licensee issued a press release.
Region IV received notification of this occurrence by telephone from the NRC senior resident inspector at the Diablo Canyon Power Plant at 11:20 a.m. PST, on December 22, 2003.
Region IV has informed EDO/NRR/PA.
This information has been discussed with the licensee and is current as of 7 a.m. PST, December 23, 2003.
CONTACTS: William B. Jones (817) 860-8147 or David Proulx at (805) 595-2353