ML19242A315
| ML19242A315 | |
| Person / Time | |
|---|---|
| Issue date: | 07/02/1979 |
| From: | Colmar R Office of Nuclear Reactor Regulation |
| To: | Burger C Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7908010374 | |
| Download: ML19242A315 (3) | |
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JUL 2 1971 v.EMORANDUM FOR:
C. Burger, Research Program Manager, Structural Engineering Research Branch, Reactor Safety Research FRCM:
R. Co: mar, Plant Systems Branch, Division of Operating Reactors EUBJECT:
REVIEW OF EG&G CRAFT REPORTS ON TAP (A-1), WATER HAFF.E R I have reviewed the foliowing EG&G draft regorts submitted in ful-fil' ment of some of the subtasks of TAP A-1, Waternammer, and I nave the following ccm.ents.
At this stage of completion in this program, it is not possible to provide a comprehensive, in-depth, technical evaluation of these reports.
The current review is limited to such matters as the identification of any technical results requiring clarification, possible misrepresentations of NRC policy, consistency of technical ccnclusions, and other details such as the satisfactory fulfillment of the work statement and the general quality of the report.
1.
" A State-of-the-Art Literature Review of Waterha=er," Report No.
RE-A-79-044 by J. C. Watkins and R. A. Berry, April 1979 (EG&G).
The authors have presented a very extensive bibliography of works on the general subject of transient hydrodynamics but it is not clear now useful this material will be for NRC.
The authors have evaluated the features of the various hydraulic codes in general tenns but not in terms of their specific aoplicability or usefulness to the study of the waternammer prcolems.
It is not clear, for example, whether the general limitations of any par 'cular code would be too restrictive to apoly to waternammer problems. Moreover, it would have beer, useful to know how the codes may be ranked in terms of the suitability for the arcbiets of interest to use at NRC.
For examale, in the discussion cf tne (-Fix code, the authors did not identify the fact.nat tnis code as it presently exists was used unsuccessfully by EG&G to analyze the steam oubble collapse waterhamer in Task 4.4 of this same problem, TAP A-1.
a of the In adcition, the discussion of colu:m separaticn en cage report is poor, ir not incerect.
And, finally, the autnors' abili ty to use Englisn grammar, syntax, vocabulary, and writing style.s su: standard.
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. 2.
" Analysis Tool For Predicting Transient Hydrodynamics In Nuclear Piping Systems Contains Swing Check Valves" by R. A. Berry, Report No. RE-A-78-261, Rovember 1978 (EG&G).
In this report RELAP 5 was adapted to describe the systems hydrodynamics causing a swing check valve to close following a completa, instantaneous pipe break just upstream of the valve.
The object of this study was to formulate an analytical tool witn whic to calculate the waterhammer forces associated with the rapid check valve c asure following the pipe break.
A proper description of the hydrodynaL1, is complicated by the flashing, two-phase, choked flow condition that folias shortly af ter the pipe break.
Because the calculation of the hydrodynamics forces on the check valve is made difficult by the complicated pipe break flow, every opportunity to verify the results is important.
In this regard " typical pressure gradient" curve of figure 3 of the EG&G report is ambiguous and it is essential that this figure be clarified in order to increase our confidence in the results of the EG&G program.
Moreover, the sample calculation provided by EG&G is for a break which is located about 14 feet from the valve instead of upstream of the valve as required by the original work statement.
It is to be noted that the purpose and value of the sample calculation is primarily to provide a test of the code in order to establish that the results can be judged to be reasonable. A sample case in which the break is just upstream of the valve is the mos,t stringent and would be the best test of the code.
It is essential that this case be calculated as soon as possible and it is highly recommended that such a case be calcu-lated anc figure 3 be clarified before the report is released in order to assure us that the code results are reasonable.
3.
" Review and Evaluation of Actual and Potential Waterhammer Events in Nuclear Plants" by R. L. Chapman, O. M. Hanner, Jr., and M. E. Wells, Report No. CAAP-TR-042, February 1979.
This report was reviewed within PSB some time ago and the draft comments were sent to you recently under separate cover.
The report contains useful information but our comments suggest that the report could be improved significantly.
Among the principal improvements would be an evaluation of the available data, originating possible new scenarios by EG&G that mignt lead to i1 sights into possible new sources of damaging waternammer occurrences, and substantive recormendations by EG&G based on an evaluaticn of the safety signif,icance of these results.
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R. Colmar Plant Systems Branch Division of Operating Reactors cc:
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E. Adensam M. Aycock F. Cherny R. Giardina S. Hanauer G. Lainas S. MacKay C. Tan J. Zwolinski a
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