ML17261A147
| ML17261A147 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 11/08/1979 |
| From: | White L ROCHESTER GAS & ELECTRIC CORP. |
| To: | Ziemann D Office of Nuclear Reactor Regulation |
| References | |
| TASK-05-04, TASK-RR NUDOCS 7911140293 | |
| Download: ML17261A147 (2) | |
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ROCHESTER GAS AHD ELECTRIC CORPORATIOH
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89 EAST AVEHUE, ROCHESTER, H.Y. 146'9 4
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November 8, 1979 Director of Nuclear Reactor Regulation Attention:
Dennis L. Ziemann, Chief Operating Reactors Branch
$ 2 U. S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
System Pressure Test Restriction for Steam Generators and Associated Feedwater and Hain Steam Piping R.
E. Ginna Nuclear Power Plant N1 Docket No. 50-244
Dear Mr. Ziemann:
Zn association with the replacement of the feedwater piping elbows to the steam generator's nozzles during July of this
- year, we performed a system pressure test (hydrostatic test) at a pressure equal or greater than 110% of the lowest mechanical relief valve setpoint of the system.
The test was performed as part of the repair program,
- however, the intent was to use this test as the required (Section Xl Article IWC-5000) 10 year system hydrostatic test.
The hydrostatic test pressure was reduced from that required by Article IWC-5000, which is a pressure of 1.25 times the lowest pressure setting of the safety valves, due to the procedural restriction we have established of never exceeding a 800 psig pressure drop from the secondary side to the primary side of the steam generator tube sheet.
The 800 psig pressure drop restriction was established early in the plant life due to the experiences of some plants with primary side tube sheet cladding separation.
Ginna steam generators have never experienced any problems with cladding separation, and we feel that the administrative pressure restriction has helped insure the integrity of the cladding.
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V ROCHESTER GAS AND ELEC CORP.
'o>TE November 8, 1979 Dennis L. Ziemann
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Performance of the secondary side hydrostatic test on the steam generators and associated piping requires a very complex, procedure which pressurizes the primary side to a pressure just under the overpressurization criteria without heating up the primary system.
Following this procedure allows for pressurization of the secondary side to a pressure just over 110% of the lowest setting (1085 psig) of the safety valves.
In order to achieve the code require 1.25% of the lowest setting of the safety valves would require the primary system to be heated up to a minimum of 160'F which would result in a problem with heat balance and a potential operational problem during this procedure.
Incorporating this much complexity into a test procedure and the administrative controls necessary to assure a proper and safe test is a situation that plant management would prefer to minimize.
Therefore, we are requesting relief from the Section XI, Article IWC-5000 pressure requirement of 1.25 times the lowest setpoint pressure of the safety valves.
In lieu we would request the acceptance of the 1.10 times this pressure which we utilize and still assure our cladding integrity.
Along with this system pressure test, the steam generators are subjected to the normal volumetric and surface exami-nations required by Section XI of the Code.
The associated feedwater and main steam piping is in an augmented inservice inspection program due to the high energy break criteria which continues to assure its integrity. If at any time a secondary side leak develops due to a problem with the steam generators or their associated piping, the leak detection systems in containment would provide assurance that early corrective action could be taken.
If you have any further questions on our request, please contact us.
Very truly yours, L. D. White, Jr.
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