ML021440118
| ML021440118 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 06/11/2002 |
| From: | Anthony Mendiola NRC/NRR/DLPM/LPD3 |
| To: | Blanch P - No Known Affiliation |
| Sands, S, NRR/DLPM/PD3-2, 415-3154 | |
| Shared Package | |
| ML021440588 | List: |
| References | |
| TAC MB5058, Y020020142 | |
| Download: ML021440118 (3) | |
Text
June 11, 2002 Mr. Paul M. Blanch 135 Hyde Rd.
West Hartford, CT 06117
Dear Mr. Blanch:
Thank you for your E-mail correspondence to the Nuclear Regulatory Commission (NRC) dated May 11, 2002. Your E-mail forwarded a message from W. R. Corcoran of Nuclear Safety Review Concepts, regarding General Design Criterion (GDC) 32 and the difficulty Davis-Besse had in inspecting the reactor pressure vessel (RPV) head.
The GDC were established in February of 1971 (36 FR 3256) and were intended to provide guidance in establishing the principal design criteria for water cooled nuclear power plants.
Davis-Besse was designed, constructed, and built previous to the development of the GDC in 10 CFR Part 50, Appendix A and thus was not required to meet the criteria. The actual design of Davis-Besse was evaluated against the GDC in effect and was determined to conform with the intent of the criteria. GDC 32 indicates, components which are part of the reactor coolant pressure boundary shall be designed to permit (1) periodic inspection and testing of important areas and features to assess their structural and leaktight integrity, and (2) an appropriate material surveillance program for the reactor pressure vessel. With respect to Criterion 32 and inspection of the reactor coolant pressure boundary, this is achieved in accordance with the requirements of American Society for Mechanical Engineers Boiler and Pressure Vessel Code,Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components. At Davis-Besse, access for inspecting the top of the reactor vessel head is accomplished through 18 rectangular openings or weep holes that are 5x7 inches in size. These openings are at the bottom of the service structure attached to the vessel head. Visual inspections of the vessel head have typically been accomplished using small video cameras inserted into the weep holes. Based on this information, the staff had concluded that Davis-Besse had access to perform inspections, as described above, and thus met the intent of the GDC 32.
As discussed in your E-mail, the licensee initiated a modification in March of 1990, to install additional access ports in the service structure to facilitate inspection and cleaning of the vessel head. This modification was canceled in 1992, because the licensee determined that the current inspection techniques were adequate. This request for modification of the service structure was reinitiated in May of 1994 to install openings in the control rod drive mechanism service structure to allow thorough inspection and cleaning of the reactor vessel head. The modification was approved in July of 1994, but remained unfunded until November of 1998, when it was scheduled for implementation in 2002. This modification would have provided better access for inspections and allowed for complete cleaning of the RPV head area.
P. Blanch In conclusion, I would like to thank you for your correspondence and to let you know NRC is closely monitoring the Davis-Besse issue.
Sincerely,
/RA/
Anthony J. Mendiola, Chief, Section 2 Project Directorate III Division of Licensing Project Management Office of Nuclear Reactor Regulation
ML021440118 Incoming: ML021440556 Package: ML021440588 OFFICE PM:LPD3-2 LA:LPD3-2 BC:EMCB
- SC:LPD3-2 NAME SSands CRosenberg for THarris WBateman AMendiola DATE 06/11/02 06/11/02 05/28/02 06/11/02