From: Stutzke, Martin
Sent: Monday, March 14, 2011 9:51 AM
To: Coyne, Kevin
Subject: PRA Info on Tsunamis and Aftershocks

The Diablo Canyon PRA considered a tsunami leading to flooding of the ASW pumps. Nothing in the San Onofre PRA on tsunamis.

Seismic PRAs do not consider damage from earthquake aftershocks. To do so, you’d need to predict the fragility of the plant SSCs following the main shock.

Marty
Martin A. Stutzke
Senior Technical Advisor for PRA Technologies
Division of Risk Assessment
Office of Nuclear Regulatory Research
U.S. Nuclear Regulatory Commission
(301) 251-7614

From: Mathew, Roy Iola
Sent: Tuesday, March 15, 2011 1:17 PM
To: Hiland, Patrick; Skeen, David; Wilson, George IY ((–
Subject: Station Blackout for US plants

Here is a write-up for station blackout, in case somebody is looking for it.

The NRC designated station blackout (SBO), which is a loss of all offsite and onsite ac power concurrent with a turbine trip, as Unresolved Safety Issue A-44 in 1980. In 1988, the Commission concluded that additional SBO regulatory requirements were justified and issued the SBO rule (Title 10 Code of Federal Regulations [CFR] Section 50.63 [10 CFR 50.63]) to provide further assurance that a loss of both offsite and onsite emergency ac power systems would not adversely affect public health and safety.

10CFR50.63 Requirement: Loss of all alternating current power.

Each light-water-cooled nuclear power plant licensed to operate must be able to withstand for a specified duration and recover from a station blackout as defined in Sec. 50.2.

As a result of the SBO rule all plants have (1) established SBO coping and recovery procedures; (2) completed training for these procedures; (3) implemented modifications as necessary to cope with an SBO; and (4) ensured a 4- 16 hour coping capability.

There are 44 Units that rely on Battery power to cope with a SBOý
There are 60 Units that have opted to use an alternate AC source

The NRC staff reviewed the responses from each licensee and issued a SER accepting the proposed coping methods

Related articles

• NRC – Dominion – Overview of North Anna Nuclear Power Plant Earthquake Response and Restart Readiness Demonstration Plan (enformable.com)
• March 14th, 2011 – Seismic PRAs do not consider damage from earthquake aftershocks – Need to predict the fragility of the plant SSCs following the main shock (enformable.com)
• November 1, 2011 Category 1 public meeting – NRC’s restart review and inspection of North Anna Nuclear Power Station following the earthquake of August 23, 2011 (enformable.com)
• Workers Evacuated After Incident at 3:10 Pm at San Onofre Nuclear Power Plant (enformable.com)
• April 4th, 2011 – station blackout and other malfunctions/failures from the earthquake, possibly even something close to a design basis accident? (enformable.com)
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• March 24th, 2011 – Limerick and TMI Report Finding I-131 in Rainwater Samples (enformable.com)
• April 1st, 2011 – It always concerned me – Japan/China building nuclear units in the most earthquake(resulting tsunami) prone areas of the world (enformable.com)
• March 23rd, 2011 – The EPA took RADNet down because they were getting data from ‘other’ sources (enformable.com)
• March 27th, 2011 – NRC Japan Team – Upon your return, please “reply All” to this email (enformable.com)
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• March 23rd, 2011 – Regarding the NRC “Screening Process” – Never hurts to reinforce what’s already been stated (enformable.com)
• March 16th, 2011 – The NRC Thought The Best Response After Fukushima Was to Verify What Licensees Were Already Required To Do (enformable.com)

• Tags: BWR, ENENews, Fukushima Daiichi, March 2011, Nuclear, Nuclear Regulatory Commission, RADNet, San Onofre Nuclear Generating Station, TEPCO