ML20100B095
| ML20100B095 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 03/22/1985 |
| From: | Crouse R TOLEDO EDISON CO. |
| To: | Stolz J Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20100B099 | List: |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-2.B.1, TASK-TM 1123, TAC-57291, NUDOCS 8503260372 | |
| Download: ML20100B095 (2) | |
Text
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Docket No. 50-346 License No. NPF-3 Toteco
%mus EDISON Serial No. 1123 RICHAno P. CROUSE March 22, 1985 ve. %
Nucies 14191259-5221 Director of Nuclear Reactor Regulation Attention:
Mr. John F. Stolz Operating Reactors Branch No. 4 Division of Licensing
' United States Nuclear Regulatory Commission Washington, D. C.
20555
Dear Mr. Stolz:
'NUREG-0737, Item II.B.1, required the installation of reactor coolant system vents; subsequently the requirement was embodied in the Code of Federal Regulations as 10 CFR 50.44(c)(3)(iii).
In your Safety Evaluation of October 5, 1983 (Log No. 1384), regarding
- the installation of the reactor coolant system high point vents for the Davis-Besse Nuclear Power Station, Unit No. 1, it was identified that the vent system is an extension of the reactor coolant pressure boundary and must_ meet applicable inservice inspection requirements described by 10 CFR 50.55(g).
ASME Boiler and Pressure Vessel Code Section XI of the 1977 Edition through the Summer, 1978 Addenda, requires quarterly stroke testing of the high point vent valves. provides an alternative test based upon an April 22, 1977 letter from the Nuclear Regulatory Commission (NRC), providing NRC staff
. guidelines for excluding tests of certain valves during plant operation.
During plant operation, failure of the high point vent valves subjected to testing would cause a loss of system pressure boundary and vent radio-active material into the containment atmosphere.
Please. find attached five copies of the revised pages of the Inservice Inspection Valve Program. Any additions to the program that become neces-sary during the remainder of the 120 month interval, which do not meet the code testing requirements, will be implemented as needed. A fully docu-mented notification to the NRC will be placed on the docket subsequent to implementation of the changes.
Enclosed is.a check for $150, as required by 10 CFR 170.12(c).
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-Very truly yours, 8
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- "503260372 8503228BA'
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cc: DB-1 NRC Resident Inspector
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Pete Whold, NRC Region III THE TOLEDO EDISON COMPANY EDISON PLAZA 300 MADISON AVENUE TOLEDO, OHIO 43652
Dock 3t No. 50-346 License No. NPF-3 Serial No. 1123 March 22, 1985 Page 1 Alternative Test Number 30 Components: RC11, RC200, RC239A, SV4608A and B, and SV4610A and B, shown on P&ID Drawing No. M-030.
Function:
The Pressurizer vent valves vent to the Pressurizer Quench Tank. The hot leg vent valves vent to the_ containment atmosphere. The safety function of the Reactor Coolant System (RCS) high point vents is to restore core cooling by venting non-condensable gases from the RCS following an inadequate core cooling event. The RCS high point vents are also used to enhance core cooling, by lowering RCS pressure to increase High Pressure Injec-tion or Makeup flow, following an event that.causes loss of primary to secondary heat transfer. The Pressurizer vent may also be oper-ated in a cyclic manner to reduce RCS pressure following an event that causes loss of Pressurizer Spray.
ASME Section III Code Class:
1 LTesting Requirements: ASME Section XI, IWV Category B, active valves requiring quarterly stroking.
Basis for Alternative Testing: A loss of system function could occur if the valves failed in the closed position while cycling or partial stroking during normal plant operation.
This would result in a loss of the ability to vent _non-condensable gases in a post-accic'ent situation.
Cycling or partial stroking of hot leg vent valves during normal plant operation would vent reactor coolant to containment atmosphere, if the valves failed to seat properly.
If a leak should occur, this could lead to a plant shutdown due to exceeding Reactor Coolant System unidentified leakage of 1 gpm or 10 gpm identified leakage from the Reactor Coolant System, per Technical Specification 3.4.6.2.
In accordance with NRC staff guidelines issued to Toledo Edison on April 22, 1977, for excluding valve exercise tests, the above valves, when exercised (cycled), could put the plant in an unsafe condition and, therefore, should not be tested.
Alternative Testing: The high point vent valves will be full stroke tested during those entries into cold shutdown and at each cold shutdown lasting more than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, but not more frequently than once every three months.
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