ML17249A343
| ML17249A343 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 11/30/1979 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17249A342 | List: |
| References | |
| TASK-05-13, TASK-5-13, TASK-RR NUDOCS 7912190062 | |
| Download: ML17249A343 (4) | |
Text
SAFETY EVALUATION REPORT, STEAM GENERATOR WATER HAMMER GINNA NUCLEAR PLANT DOCKET NO. 50-244 NOVEMBER 1979 yoiaxg0, (g6Z
- 1. 0 INTRODUCTION Steam generator water hammer has occurred, in certain nuclear power plants as a result of the rapid condensation of steam in a steam generator feedwater line and the consequent acceleration of a slug of water which upon impact within the piping system causes undue stresses in the piping and its support system.
The significance of these events varies from plant to plant.
Since a total loss of feedwater could affect the ability of the plant to cool down after a reactor shutdown, the NRC is concerned about these events occurring, even though an event with potentially serious consequences is unlikely to happen.
Because of the continuing occurrence of water hammer events, the
- NRC, in September
- 1977, informed all PWR licensees that water hammer events due to the rapid condensation of steam in the feedwater lines of steam generators represented a safety concern and that further actions by licensees for Westinghouse and Combustion Engineering designed nuclear steam supply systems are warranted to assure that an acceptably low risk to public safety due to such events is maintained.
Accordingly, these licensees were requested to submit proposed hardware and/or procedural.
modifications, if any, which would be necessary to assure that the feedwater lines and feedrings remain filled with water during normal as well as transient operating conditions.
At the same time, the NRC provided each PWR licensee with a copy of its consultant's
- report, "An Evaluation of PWR Steam Generator Water Hammer",
The means employed at the Ginna Nuclear Plant to reduce the potential for steam generator water hammer include J-tubes, automatic initiation of auxiliary feedwater flow, administrative controls to limit auxiliary feedwater flow and short horizontal piping adjacent to the steam generator.
- 2. 0 EVALUATION Our consultant,
- EG8G, Idaho Inc., prepared the attached evaluation of steam generator water hammer at the Ginna Nuclear Plant as part of our technical assistance program.
(Letter from J.A.
Dearien,
EG&G, to R.E. Tiller, DOE, dated October 17, 1979.)
We have reviewed this report together with the licensees submittals listed under item 4.0.
- 3. 0 CONCLUSION Based on our knowledge of water hammer phenomena, and our review of the licensees responses and the enclosed evaluation report, we concur with our consultants'onclusion that the means for reducing the potential for steam generator water hammer at this facility are adequate.
These means are, therefore, acceptable to the staff and no further action is required of the licensee with regard to steam generator water hammer.
4.0 REFERENCES
1.
G.E. Green, Rochester Gas and Electric Corp.
(RGE), letter to J.P. O'Reilly, NRC, "R.E. Ginna Nuclear Power Plant, Unit No. 1, Failure of Sensing Line on 'B'uxiliary Feedwater Pump, Abnormal Occurrence 73-6 and 73-7," August 1, 1973.
2.
K.W. Amish, RGE, letter to R.T. Colson, NRC, "Feedwater Piping Transient Evaluation," July 17, 1975.
3.
L.D. White, Jr.,
RGE, letter to R.A. Purple, NRC, "Secondary System Fluid Flow Instability, R.ED Ginna Nuclear Power Plant, Unit No. 1,"
October 31, 1975.
4.
K.W. Amish, RGE, letter,. to R.A. Purple, NRC, "Specific Changes Made at Ginna Relative to Water Hammer," January 30, 1976.
5.
L.D. White, Jr.,
RGE, letter to D. Ziemann,
- NRC, "Steam Generator Mater Hartmer Prevention,"
June 15, 1978.
ECFZCP Idaho, Inc.
Il P. O. Box 1625 Idaho Falls, Idaho 83401 October 17, 1979 her.
R.
F.. Tiller, Director Reactor Operations and Programs Division Idaho Operations Office -
DOE Idaho Falls, ID 83401 GINHA P01IER STATION STEAtl GENERATOR MATER HANtiER TECHNICAL EVALUATION (A6257) - JAD-210-79
Dear Hr. Tiller:
The attachment completes the assessment of the effectiveness of the existing means to reduce the potential for steam generator water hammer at the Ginna Power Station.
The assessment has shown that under conditions which are most conducive to water hammer in the feedwater system (specifically,
,uncovered and draining feedrings and feedwater piping subjected to admission of cold auxiliary feedwater),
the means to reduce the potential for water hammer at this facility are adequate to maintain sufficiently full feedrings and feedwater piping until feedring recovery occurs.
Therefore, since keeping the.feedrings and feedwater piping full of water is the criterion for this evaluation, we find that the means to reduce the potential for steam generator water hammer at this facility are adequate.
This transmittal constitutes partial fulfillment (one of the four plants to be reviewed) of Node LA4, of the A6257 PERT Chart dated September 25, 1979.
Very, truly yours, LMF:tn J.
A.
Dearien,
tlanager Code Assessment and Applications Program
Attachment:
As stated cc: PS.
D. I<acKay, NRC-DOR R. H. Kiehn, EG&G Idaho w/o attach.