ML18040A937
| ML18040A937 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 05/12/1989 |
| From: | Thadani M NRC |
| To: | Varga S NRC |
| Shared Package | |
| ML17156B270 | List: |
| References | |
| NUDOCS 8907120202 | |
| Download: ML18040A937 (1) | |
Text
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~O 4y*y4 UNITEDSTATES NUCLEAR REGULATORYCOMMISSION WASHINGTON,o. C. 20555 ihy 12, 1989 NOTE TO:
THROUGH:
FROM:
Steven A. Yarga Bruce A. Boger Malter R. BtItler Mohan C. Thadanf
SUBJECT:
MEETING WITH PENNSYLVANIA POMER AND LIGHT COMPANY Per your request of May 5, 1989, I have prepared the following suIIrnary of the subject meeting dealing with the PPLL's presentation to NRR of fts approach to risk management, its associated studies using the IPE methodology, and some significant results of its studies.
Viewgraphs of the presentation and a list of attendees is attached.
As you know, PPKL believes fn modelfng the use of all available
- hardware, realistic operato~ actions, and inexpensIve hardware modifications to deal with the severe accident sequences in its IPE studies.
Based on fts realistic approach (unlike the conservatfve approach generally used fn such analyses) the PPhL believes that it can develop detailed procedures and operator training to assure that all actions that can reasonably be taken (during postulated severe accident sequences) can be taken with high degrees of success.
Such success criteria are also incorporated in IPE studies.
PPKL believes that conservative assumptions can mask the potential corrective actions that can be taken for recovery from postulated severe accidents.
The PPRL studies using fts realistic approach to management of risk at Susquehanna and realistic Iredelfng in IPE methodology show some interesting results.
Following are some of the results which appear to have significance to some of the issues which the KRC fs presently actively trying to resolve.
1.
PPKL analysfs shows that by operating the RMCU system fn the blowdown mode, the plant can be stabilized from sequences which result in loss of contafnment heat removal capability.
Consequently, this action clfmfnates a significant fraction of accident sequences from thc contributors to the overall cora damage frequencies.
2.
ATN sequences can alaest alwgrs be successfully terminated fn hot shutdown (by using realistic success criteria and plant unfque features).
3.
The use of diverse water in3ectfon sources sharply reduces BXR core damage frequency.