ML022520032
| ML022520032 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 10/30/2002 |
| From: | Meserve R NRC/OCM |
| To: | Skinner P State of NY, Office of the Attorney General |
| Hopkins J , NRR/DLPM, 301-415-3027 | |
| Shared Package | |
| ML022520054 | List: |
| References | |
| CORR-02-0209, G20020507 | |
| Download: ML022520032 (2) | |
Text
October 30, 2002 Mr. Peter Skinner, Chief Scientist Office of the Attorney General State of New York Albany, New York 12224
Dear Mr. Skinner:
I am responding on behalf of the Nuclear Regulatory Commission (NRC) to your letter of August 14, 2002, to Dr. Edwin Hackett of the NRC Lessons Learned Task Force (LLTF) for Davis-Besse. You commented that the cavity in the Davis-Besse reactor pressure vessel head caused by boric acid corrosion could have been discovered earlier if better procedures were in place.
The NRC established the LLTF to conduct an independent evaluation of the NRCs regulatory processes related to issues associated with the reactor vessel head degradation in order to identify and recommend areas for improvement. Areas evaluated include the reactor oversight process, the regulatory process, generic communications, and other areas within the NRC framework. The LLTF report was issued publicly on October 9, 2002, and is available on the NRCs web site at:
http://www.nrc.gov/reactors/operating/ops-experience/vessel-head-degradation/news.html. A team of NRC senior managers is now reviewing the report and will make recommendations in November for Commission action.
You requested that an independent unit be established in the NRCs Office of the Inspector General (OIG) to investigate off-normal and other conditions before accidents occur.
The NRC staff has the responsibility to evaluate the operation of nuclear power plants and has ongoing programs to review and investigate off-normal conditions at these facilities. The OIG, by contrast, is responsible for conducting audits and investigations to ensure the integrity of NRCs programs and operations. The OIGs responsibilities do not include independent technical or engineering evaluations of licensee operations. Any expansion of the OIGs role would simply duplicate NRC staffs responsibilities.
Additionally, you questioned whether the NRC proactively dispatches... technical teams to investigate off-normal problems that may have been overlooked by the licensee and onsite inspectors. The NRCs Reactor Oversight Process (ROP) includes (1) inspections of licensee corrective action programs through biennial NRC team inspections that are part of the baseline inspection program; and (2) supplemental inspections that are performed when performance indicator thresholds are crossed or when risk significant findings arise from baseline inspections. The breadth and depth of these supplemental inspections varies according to the risk significance of the performance indicator results or baseline inspection findings.
Mr. P. Skinner In your letter, you also indicated that,... the stainless steel cladding inside the reactor vessel head prevented a severe loss of coolant accident, which could have progressed to a meltdown. Following the identification of the corrosion in the reactor vessel head at Davis-Besse, the staff performed analyses in which the break size was postulated to be approximately the size of the degraded area on the Davis-Besse reactor vessel head. In order to bound the consequences of a rupture of the degraded area, a complete failure of the control rods to enter the core was analyzed concurrent with the postulated break. The consequences were found to be similar to those of piping breaks analyzed in the plants Final Safety Analysis Report. The results showed that the reactor would shut down by core voiding and boric acid addition without core uncovery or overheating. The plants safety systems would have prevented a meltdown.
The NRC will consider the technical issues raised in your letter as we review our regulatory activities in light of the Davis-Besse reactor pressure vessel head corrosion. We take seriously our responsibility for protecting the public health and safety and we strive to monitor Davis-Besse and all other nuclear power reactors to ensure they operate in a manner that adequately protects public health and safety and the environment. Thank you for bringing your concerns to the attention of the NRC.
Sincerely,
/RA/
Richard A. Meserve