ML18051A624
| ML18051A624 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 09/29/1983 |
| From: | Toner K CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| TASK-15-02, TASK-15-2, TASK-RR NUDOCS 8310060047 | |
| Download: ML18051A624 (4) | |
Text
consumers Power company General Offices: 1945 West Parnall Road, Jackson, Ml 49201 * (517) 788-0550 September 29, 1983 Dennis M Crutchfield, Chief Operating Reactor Branch No 5 Nuclear Reactor Regulation US Nuclear Regulatory Commission Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT - SEP TOPIC XV-2 "SPECTRUM OF STEAM PIPING FAILURES INSIDE AND OUTSIDE CONTAINMENT (PWR)" -
COMMTTMENTS FOR EVALUATION AND MODIFICATION Consumers Power Company documented in a submittal dated March 31, 1982 a commitment to perform by the end of the Cycle 7 refueling outage appropriate modifications to make the Main Steam Isolation Valve (MSIV)/Main Steam System (MSS) configuration single-failure-proof with respect to a two-steam-generator blowdown event.
In a later submittal dated August 15, 1983, Consumers Power Company requested that the NRC grant a time extension of one operating cycle beyond the aforementioned commitment in which to make the modifications.
As stated in the August submittal, the time extension will provide Consumers Power Company the opportunity to finalize its probabilistic risk assessment (PRA) and cost-benefit analysis to determine more accurately the safety significance of the event as well as the most cost-effective modification to reduce the likelihood of such an event should modification prove necessary.
As documented in a transmittal dated September 14, 1983, the NRC Staff granted our request and recommended that Consumers Power Company provide additional evaluation and testing to supplement our PRA and cost-benefit analysis.
The purpose of this letter is to formally document our intentions by providing as an attachment a summary listing of future Consumers Power Company activities necessary to comply with our revised commitments and the Staff's recommendations.
Kerry A Toner Senior Licensing Engineer CC Administrator, Region III, USNRC NRC Resident Inspector - Palisades Attachment OC0983-0018A-NL02 8310060047 830929 PDR ADOCK 05000255 P
OC0983-0018B-NL02 ATTACHMENT Consumers Power Company Palisades Plant Docket 50-255 SEP TOPIC XV-2 "SPECTRUM OF STEAM PIPING FAILURES INSIDE AND OUTSIDE CONTAINMENT (PWR)" -
COMMITMENTS FOR EVALUATION AND MODIFICATION September 29, 1983 2 Pages
No
- 1.
- 2.
- 3.
SUMMARY
LISTING OF FUTURE CONSUMERS POWER COMPANY ACTIVITIES RELATED TO SEP TOPIC XV-2 PALISADES PLANT Activity Perform reliability testing of each existing MSIV while the plant is as close to full operating tempera-ture as practical.
Submit to the NRC final PRA and cost-benefit analysis which reveals the actual safety significance of the two-steam-generator blowdown event as well as the most cost-effective modification (if modification is proven necessary by the PRA) to reduce the likelihood of the event.
Submit to the NRC the following evaluations which serve to supplement activity No 2 above:
3.a An _evaluation of the thermal-hydraulic response of the steam generator secondary side during and after the two-steam-generator blowdown event.
3.b A determination of the number of cooldown cycles that would cause *the steam generator vessel, tubes or tube sheet to fail.
3.c A determination of the number of cooldown cycles that would occur during and after the event.
3.d Should it be determined that tube failure will occur, an evaluation of the impact on containmept failure including a description of the model utilized to analyze the consequences.
3.e _ A determination of the likelihood of a MSLB outside of containment and depending on the probability of such an event:
a) an evaluation of the means by which long-term cooling (LTC) would be accomplished taking into account that the spilled coolant would not be filling the sump to provide a LTC supply of water, and b) a description of the model utilized to analyze the consequences.
3.f An evaluation of the effect of various MSLB sizes on the plant response.
3.g An evaluation of the means by which the operator would prevent excessive cooldown that could pull a void on the primary system; especially if there exists a LOCA through the steam generators.
OC0983-0018C-NL02 1
Completion Date by the end of the Cycle 6 (1983) refueling outage by Sept 1, 1984 by Sept 1, 1984
No Activity 3.h An evaluation of the effect of the cooldown and repressurization on the primary system to determine whether or not pressurized thermal shock of the reactor vessel would occur.
3.i A description of any procedural revisions, found to be necessary during the aforementioned evaluations, to assure the secondary system decay heat removal func-tion and to avoid pressurized thermal shock of the reactor vessel.
- 4.
If shown necessary by the PRA identified in activity No 2 above, complete plant modifications to make the MSIV/MSS configuration single-failure-proof with respect to the two-steam-generator blowdown event.
OC0983-0018C-NL02 Completion Date by the end of Cycle 8 (1986) refueling outage 2