ML030370157
| ML030370157 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood  |
| Issue date: | 02/14/2003 |
| From: | Anthony Mendiola NRC/NRR/DLPM/LPD3 |
| To: | Mulligan M New England Coalition on Nuclear Pollution |
| Mendiola, AJ, NRR/DPLM/LPD III-2, 415-10 | |
| Shared Package | |
| ML030410447 | List: |
| References | |
| Y020030016, Y020030017, Y020030018 | |
| Download: ML030370157 (5) | |
Text
February 14, 2003 Mr. Michael Mulligan New England Coalition on Nuclear Pollution 5 Woodlawn Lane Hinsdale, NH 03451
Dear Mr. Mulligan:
This is in response to your e-mails dated January 17, January 18, and January 20, 2003, addressed to Mr. Victor L. Dricks, Office of Public Affairs, Nuclear Regulatory Commission, regarding your safety concerns at the Braidwood and Byron Nuclear Stations. Your concerns are related to:
- 1. The sequential testing of main steam safety valves (MSSVs) instead of simultaneous testing.
- 2. The adequacy of Inconel x-750 disk material and the engineering basis for its selection.
- 3. The adequacy of MSSV testing, testing frequency and the acceptance criteria.
- 4. The effects of the rate of change in system pressure on MSSV setpoints.
- 5. The adequacy of the American Society of Mechanical Engineers (ASME) code requirements and the testing sample size.
We have reviewed your concerns and our response to your concerns is as discussed below:
Concern 1 - This was raised by you in your e-mail to Mr. Victor L. Dricks dated December 20, 2002, and were addressed in our letter to you dated January 9, 2003.
Concern 2 - You raised a question about the appropriateness of the use of the X-750 disk material in MSSVs since one of the Byron plant valves had high initial lift settings due to mettalic bonding. The Byron licensee has evaluated the safety significance of the actual setpoints experienced and have determined that the plant operated within all safety limits. In accordance with 10 CFR 50.59, the licensee is permitted to make certain changes to components, such as MSSVs without prior NRC approval provided the requirements in 10 CFR 50.59 are satisfied. The purpose of the change to the X-750 material is to improve setpoint performance. The setpoint performance of the new material is continuing to be evaluated through inservice experience. The 10 CFR 50.59 changes are subject to Nuclear Regulatory Commission (NRC) inspections and audits in accordance with Reactor Oversight Process. Licensees are also required to meet 10 CFR 50.65 (Maintenance Rule) to monitor the performance or condition of safety components against licensee established goals commensurate with safety taking into account industry-wide operating experience. Therefore, we did not substantiate this concern.
Concern 3 - You also raised questions about the adequacy of MSSV testing regarding when tests are performed and when valve setpoints may actually be out-of-specification. Testing is performed in accordance with ASME Code requirements. Test results provide information about the inservice condition of the valves and are used to identify needed corrective action,
M. Mulligan even if the tests are performed at the end of plant operating cycles. When MSSVs fail setpoint tests, they still possess their relieving capacity at the higher (or lower) setpoints experienced.
In addition, there is significant margin, both for overpressure protection and for structural integrity of safety components. Therefore, we did not substantiate this concern.
Concern 4 - With respect to change in system pressure on MSSV setpoints, MSSVs respond quickly at their setpoints relative to system pressure transients, and any effects due to the rate of pressurization are considered in overpressure analyses. Therefore, we did not substantiate this concern.
Concern 5 - The ASME code requirements are developed based on a consensus of industry practice. We recommend that you pursue any technical questions on code requirements with the ASME Code Committee.
Based on the above, we do not plan to take any further action on your concerns. Your concerns regarding the safety culture at NRC have been referred to the Office of Inspector General for its consideration.
Thank you for bringing these issues to the attention of the NRC.
Sincerely,
/RA by LRaghavan for/
Anthony J. Mendiola, Chief, Section 2 Project Directorate III Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos. STN 50-454, STN 50-455, STN 50-456, and STN 50-457
ML030370157 Incoming: ML030360357 (2/17/03 E-mail)
ML030360362 (2/18/03 E-mail)
ML030360366 (2/20/03 E-mail)
Package: ML030410447 OFFICE PM:LPD3-2 LA:LPD3-2 BC:EMCB SC:LPD3-2 NAME MChawla THarris DTerao LRaghavan for AMendiola DATE 2/13/03 2/13/03 2/13/03 2/14/03
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ANTHONY J. MENDIOLA RESPONSE TO MIKE MULLIGAN DATED: February 14, 2003 PUBLIC PD3-2 r/f SCollins/RBorchardt (RidsNrrOd)
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