ML14161A270
| ML14161A270 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 06/12/2014 |
| From: | Uhle J Office of Nuclear Reactor Regulation |
| To: | Rhodes J State of NY, Energy Research & Development Authority |
| DiFrancesco N, NRR/JLD, 415-1115 | |
| Shared Package | |
| ML14132A287 | List: |
| References | |
| G20110225, LTR-11-0166, LTR-14-0274-1 | |
| Download: ML14161A270 (3) | |
Text
June 12, 2014 Mr. John B. Rhodes New York State Energy Research and Development Authority 17 Columbia Circle Albany, NY 12203
Dear Mr. Rhodes:
On behalf of the Nuclear Regulatory Commission (NRC), I am responding to your letter dated April 27, 2014, in which you expressed concerns about the NRC prioritization and review schedule for the Indian Point Units 2 and 3 seismic hazard reevaluation submittals. As you are aware, we received the seismic hazard reevaluation reports for plants in the Central and Eastern United States in response to our request for information dated March 12, 2012. The licensee for Indian Point did report in the responses referenced in your letter that their reevaluated seismic hazards are higher than the safe shutdown earthquake previously evaluated as part of the licensing of the plants.
Please note that this submittal is only the first step in determining what additional evaluations and possible safety improvements might be warranted to support the longer term operation of nuclear power plants in the United States. The NRC is reviewing the reports to determine if we agree with the licensees assessments and proposed actions. It is important to note that while some of the reevaluated hazard reports, such as those for Indian Point, identify the potential for different ground motions than were assumed in analyses performed to support plant licensing, the ground motion does not by itself determine what, if any, additional risks are posed to the public from the nuclear power plant. As part of the reevaluated seismic hazard submittals, licensees whose hazards were higher than their safe shutdown earthquake were requested to provide either interim actions or an interim evaluation to justify their continued operation while they performed additional evaluations. The NRC staffs review of an industry screening analysis and licensees interim evaluations concluded that no immediate changes to plant structures, systems, or components were needed for the operating plants in the United States.
The NRC recently screened and prioritized all the plant submittals to determine which plants need to perform additional analysis, such as expediting the review and modification, if necessary, of important safety systems (Expedited Approach) or the full seismic margins analysis or seismic probabilistic risk assessment.
The results of the NRCs prioritization assessment for Indian Point Units 2 and 3 place both plants in priority Group 1; therefore the full seismic analysis is due in June 2017. Plants in this group have both a relatively large increase in seismic hazard and a relatively large new ground motion estimate. Therefore, Group 1 plants will benefit most from the results of detailed seismic risk analysis and have priority in using available seismic risk expertise.
While awaiting completion of the in-depth seismic risk analyses, licensees will be performing assessments and, as appropriate, plant modifications in accordance with NRC approved guidance related to the Expedited Approach. These evaluations will determine if interim actions are necessary while the licensee performs the full seismic margins analysis or seismic probabilistic
risk assessment. The interim actions could involve, for example, strengthening the seismic capabilities of components relied upon to maintain important core cooling functions. The evaluations associated with the Expedited Approach are to be completed by December 2014.
For awareness, the NRC and the licensee for Indian Point have scheduled a public meeting on June 19, 2014, to discuss differences in NRC and licensee-calculated ground motions. At this meeting, the licensee intends to present information related to a possible request to defer completion of the Indian Point Unit 3 risk evaluation until December of 2019 by crediting activities already completed at the plant. Note the June 19th meeting will not result in an immediate decision on the possible re-prioritization but will instead begin a dialogue with the licensee on the models, assumptions, and other factors that contributed to differences between NRC and licensee estimates for seismic hazards at the Indian Point site.
The NRC continues to have confidence that plants can operate safely while more analyses are done. This confidence is based on our understanding of external hazards, reactor design, construction, and the results from previous inspections and assessments. Nuclear power plants have the capacity to withstand earthquakes larger than those assumed as part of the licensing process. This additional capacity results from nuclear power plants being designed, with safety margins, to withstand the forces of a variety of internal and external events. Many of these events create larger forces and challenges to plant structures, systems, and components than would be caused by an earthquake at the specific plant locations. The NRC is satisfied that plants can continue operation without introducing undue risk to public health and safety pending the additional analyses and possible enhancements that might result from the planned short and long-term evaluations.
If you need any additional information, please contact Nicholas DiFrancesco at 301-415-1115 or via email at Nicholas.DiFrancesco@nrc.gov.
Sincerely,
/RA/
Jennifer Uhle, Deputy Director Reactor Safety Programs Office of Nuclear Reactor Regulations
ML14132A287 (Pkg.); ML14133A004 (Incoming); ML14161A27 (Resp.)
- via email OFFICE NRR/JLD/PMB: PM*
NRR/JLD: LA*
NRR/JLD/PMB: BC NRR/JLD: D NRR: DD NAME NDiFrancesco SLent MMitchell DSkeen (WReckly for)
JUhle DATE 06/10/2014 06/10/2014 06/10/2014 06/10/2014 06/12/2014