ML20002C787
| ML20002C787 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 05/02/1974 |
| From: | Goller K US ATOMIC ENERGY COMMISSION (AEC) |
| To: | Sewell R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| Shared Package | |
| ML20002C788 | List: |
| References | |
| NUDOCS 8101100865 | |
| Download: ML20002C787 (5) | |
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UNITED STATES 4D, h ' V l* J L
ATOMIC ENERGY COMMISSION
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Docket rio. 50-155 I4ay 2,1974 Consumers Power Company ATTft: fir. Ralph B. Sewell fluclear Licensing Administrator 212 West liichigan Avenue Jackson,tiichigan 49201 Gentlemen:
On April 29, 1974, the licensee, Consumers Power Company, requested a temporary change in technical specifications for Facility License DPR-6.
The licensee requested that the requirement that the ventilation inlet valve close within 6 seconds be changed to require closure within 10 seconds.
During the refueling outage recently completed, the licensee replaced the 24" containment building ventilation supply valve with a new valve.
The old valve was replaced due to increasing leakage across the valve seat.
Both the old valve and the new valve are air operated, pressurized to open and to hold open. The valves are closed by spring action.
The new valve has a different air operator volume..The_ air operator is vented through two solenoid valves in series which have 1/4" internal vent passages.
The new valve with the larger air operator volume has been tested at the facility and while closure is accomplished within 10 seconds closure within 6 seconds cannot be achieved without undesirable changes in the valve. The licensee proposes to replace the existing solenoid valves during the summer refueling outage with solenoid valves having slightly larger internal vent passages to permit the new ventilation inlet valve to achieve the 6 second closure time.
However, delivery of such valves which comply with necessary code requirements cannot be made for several months.
Reinstallation of the original ventilation valve is an alternative to making this Technical Specification Change, however this is not desirable due to the leakage across that valve.
The large ventilation valve openings must be provided with rapid closures to prevent the release from containment of radioactive materials in the event of an accident.
For the Design Basis Loss of Coolant Accident conditions, which entail a loss of primary coolant to containment followed by release of core fission products to containment and subsequent leakage from contairment to the atmosphere, the period before fission products from the core (e.g., on the order to 50-100 seconds) are available for leakage in containment is quite long compared to valve closure times.
The change of valve closure time from 6 seconds to 10 seconds does not affect the integrity of containment with respect to containment of core fission products in the event of the loss of coolant accident.
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I Consu:ners Power Company ilsy 2,1974 cc w/encls:
cc w/encls and copy of CPC filing 4/29/74:
Mr. Paul A. Perry, Secretary Mr. D. John Beck Consumers Power Company Division of Intergovernmental Relations 212 West Michigan Avenue Executive Office of the Governor Jackson, Michigan 49201 Lewis Cass Building Peter W. Steketee, Esquire Vander Veen, Freihofer & Cook Mr. Gary Williams Union Bank Building, Suite 950 Federal Activities Branch Grand Rapids, Michigan 49502 Environmental Protection Agency 1 N. Wacker Drive Mr. Ronald C. Callen Chicago, Illinois 60606 Michigan Public Service Commission Law Building Lansing, Michigan 48913 George C. F.eeman, Jr., Esquire Hunton, Williams, Gay & Gibson 700 East Main Street Richmor.d, Virginia 23212 David S. 3rollier, Esquire Hunton, Williams, Gay & Gibson 700 East Main Street Richmond, Virginia 23212 Charles E. Bayless Of Counsel Consumers Power Company 212 West Michigan Avenue Jackson, Michigan 49201 Anthony Z. Roisman, Esquire Berlin, Roisman and Kessler 1712 N Street, H. W.
Washington, D. C.
20036 Chairman County Board of Supervisors Charlevoix County Charlevoix, Michigan 49720 Charlevoix Public Library 107 Clinton Street Charlevoix, Michigan 49720
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W." - 2 B74 P
l Docket No. 50-155 Consumers Power Company ATTH: Mr. Ralph B. Sewell Nuclear Licensing Administrator 212 West Michigan Avenue Jackson, Michigan 49201 Gentlemen:
On April 29, 1974, the licensee, Consumers Power Company, requested a temporary change in technical specifications for Facility License DPR-6.
The licensee requested that the requirement that the ventilation inlet i
valve close within 6 seconds be changed to requim closure within 10 seconds.
Ouring the refueling outage mcently completed, the licensee replaced the 24" containment building ventilation supply valve with a new valve.
The old valve was replaced due to increasing leakage across the valve seat.
Both the old valve and the nes valve are air operated, pressurized to open
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and to hold open. The valves are closed by spring action. The new valve 1
has a different air operator volune. The air operator is vented through two solenoid valves in series which have 1/4" internal vent passages.
The new valve with the larger air operator volume has been tested at the facility and while closure is accomplished within 10 seconds closure within 6 seconds cannot be achieved without undesirable changes in the valve. The licensee proposes to replace the existing solenoid valves during the surraer refueling outage with solenoid valves having slightly larger internal vent passages to permit the new ventilation inlet valve to achieve the 6 second closure time. However, delivery of such valves which comply with necessary code requirements cannot be made for several months.
Reinsta11ation of the original ventilation valve is an alternative to making this Technical Specification Change, however this is not desirable due to the leakage across that valve.
The large ventilation valve openings must be provided with rapid closures to prevent the release from containment of radioactive materials in the
.f 'T,, event of an accident. For the Design Basis Loss of Coolant Accident W
conditions, which entail a loss of primary coolant to containment followed
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nt and subsequent leakage fore fission pmducts DUPLICATE DOCUMENT nds) are available for g ','
valve closure times.
Entire document previously to 10 seconds does not entered into system under:
-containment of com lant accid FL
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ANO su No. of pages:
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Form AtC-5
Consumers Power Company pi 2 1974 During the early seconds following an assumed accident, the containment atmosphere consists of a mixture of air and steam flashed from the primary coolant along with a small amount of fission gases, radioactive fission and corrosion products which were carried by the primary coolant which has flashed into steam.
For small and intemediate sized breaks, the change from 6 seconds to 10 seconds in closure time has an insignificant affect on any release of radioactivity from containment.
For large breaks, the pressure may increase toward design Ifmits within 15 or more seconds and the total amount of air and later air and steam that could escape if the upstream check valve does not close, could be nearly double for a 10 second closure time, compared to 6 second closure time.
For the first few seconds, containment air of negligible radioactivity would escape but as containment pressure continued to increase and steam air mixing occurred, the anount of radioactivity escaping would be somewhat greater for a 10 second closure time compared to a 6 second closure time. However, this increased amount would represent only a small portion of the radioactivity computed to be released in the course of the accident, less than 15 based on the time required to damage fuel. Accordingly, the increase closure time has a negligible effect on accident consequences.
The change does not othentise affect facility o
.f2[h J @k Based on the above we have concluded that temporary change of the ventilation inlet valve closum time from 6 sounds to 10 seconds does not involve a significant hazards consideration and that there is reasonable assurance that the health and safety of the public will not be endangered by operation in the manner proposed.
Accordingly, Amendment No. 5 to Facility Operating License No. DPR-6 is enclosed revising the Technical Specifications thereto to authorize the requested temporary change relating to inlet ventilation valve closure requirement. A copy of a notice which is being forwarded to the Office of the Federal Register for publication relating to this actiona,'p::j also is enclosed for your information.
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ns signed by pricouer g#pS 9
r Karl R. Goller, Assistant Director
- 9) g' Q\\p ), k Directorate of Licensing for Operating Reactors
Enclosures:
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Amendment No. 5 to M
License No. DPR-6 2.
Federal Register Nottep M
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e.ws Form AEC-SIS LRes 9-53) AECM 0260
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