ML19211C554
| ML19211C554 | |
| Person / Time | |
|---|---|
| Issue date: | 08/08/1979 |
| From: | Teh-Chiun Su Office of Nuclear Reactor Regulation |
| To: | Thadani A Office of Nuclear Reactor Regulation |
| References | |
| REF-GTECI-A-09, REF-GTECI-A-39, REF-GTECI-CO, REF-GTECI-SY, TASK-A-09, TASK-A-39, TASK-A-9, TASK-OR NUDOCS 8001110672 | |
| Download: ML19211C554 (3) | |
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UNITED STATES 8
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WASHINGTON, D. C. 20555
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AUG 8 E79 MEMORANDUM FOR:
A. Thadani, Task Manager, A-9, Reactor Systems Branch, DSS FROM:
T. M. Su, Task Manager, A-39, Containment Systems Branch, DSS
SUBJECT:
PRELIMINARY QUESTION LIST FOR GE REPORT ON STWS Per your request on August 1,1979, I have prepared the preliminary question list for the GE report titled " Assessment of BWR Mitigation of ATWS, May 1979." A copy of the list is enclosed.
Please note that the enclosed question list is intended only for discussion purposes during the coming meeting with GE on August 10.
It does not, however, represent the result of our final review on that report. Based on the current review schedule, we expect to complete our review by early September,1979. We will provide you the results of our evaluation by that time.
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T. M. Su, A-39 Task Manager Containment Systems Branch Division of Systems Safety
Enclosure:
As Stated cc:
S. Hanauer W. Butler J. Kudrick L. Ruth 1736 254 go01118
Preliminary Question List Relating.to. Sections 5.2.2 and 5.2.3 of GE Report on ATWS 1.
Provide a detailed description of ti.e methodology used to calculate ATMS SRV loads.
Information should includc the following:
a.
All assumptions used in the methodology; b.
The initial conditions such as SRV line temperature SRV line volume, suppression pool temperature, and suppression chamber pressurei c.
Data base and the associated interpretation and justification for the use of the data for ATWS conditions.
2.
It is noted tha'. the Caorso test results were used directly for the ATWS SRV loads for both Mark II and Mark III containments.
It should be recognized, however, the Caorso plant has its own plant unique conditions related to SRV design such as SRV line volume, submergence, pool area per quencher etc.
In addition, the Caorso primary systems and containment conditions during the tests were not near the ATWS conditions. Therefore, we believe that the Caorso test results should not be used without justification.
Furthermore, the complete information on the Caorso tests will not be made available for staff review until the end of this year. A generic approach for the use of the test results has not been proposed either by GE or the Mark II owners group. Based on this status, until the above information is provided, the current statistical approach described in NED0-21061-P (Mark II Containment Dynamic Forcing Functions) or NED0-ll314-08 for Mark III containment should be used.
Provide the calculated results for Mark II and III ATWS SRV loads.
1736 255
3.
Provide justification for establishing the temperature difference of 14*F betweenlocalandbulkpoolteNperature.
It should be noted that the Monticello T-Quencher tests on February,1978 were performed under certain specific operational conditions and plant unique geometry. The test results should not be used in a generic sense.
Justification is required for the application of this data base for Mark I. design.
4.
The service water temperature and initial pool temperature of 75'F were used in the calculation of pool temperature response to ATWS events. The ration &l used to justify these temperatures, i.e., the T-quencher has the capability to condense steam up to saturated local temperature, has not been substantiated. Therefore, additional information is required to justify the use of temperature below design levels.
5.
Provide the Caorso data base which was used to establish the ll*F temperature difference for Mark II and III containments.
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