ML19320B901
| ML19320B901 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 07/07/1980 |
| From: | Naughton W COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8007150476 | |
| Download: ML19320B901 (4) | |
Text
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f~'N Commonwealth Edison
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) One First National Ptara. Chicigo, minois
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7 ' Addr:ss R ply to: Post Ofhca Box 767 v/ - Chicago, Illinois 60690 x
July 7, 1980 Mr. Harold R. Denton, Director Of fice of-Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC-20555
Subject:
Zion Station Units 1 and 2 Additional Information Regarding 10 CFR 50, Appendix J. Exmeption NRC Docket Nos. 50-295 and 50-304 Reference (a):
September 26, 1975 letter from G.
J.
Pliml to K. R. Galler.
-(b):
January 31, 1977 letter from D. E.
O'Brien to K.
R. Galler.
(c):
May'll, 1977 letter from R. L.
Bolger to K.
R. Goller.
Dear Mr. Denton:
In Reference (a), Commonwealth Edison Company requested certain exemptions from 10 CFR 50, Appendix J, for its Dresden, Quad-Cities and Zion Stations pursuant to 10 CFR 50, Section 50.12.
In Reference (b), Commonwealth Edison provided additional information regarding leak rate testing of the air lock seals at Zion Station.
In Reference (c), Commonwealth Edison requested additional valves to be exempted from the requirement to do type C leakage tests.
As a result.of numerous discussions'between Commonwealth Edison and NRC Staff personnel ' including conference calls on March 3 and April _23, 1980, Commonwealth Edison agreed to s0pply additional
'information-in support of-the above referenced requests.
This information follows.
With' regard to References-(a) and (b), the. modification-to install a_ flowmeter with'a high flow alarm on the penetration pressurization:(PP)_ piping to the personnel air lock door seals has been completed.
This flowmeter is sufficiently sensitive to detect a.high leakage condition on the seals well-before reaching the Zion Station Technical Specification limit oniPP leakage.
The setpoint of: theLalarm;on.the~ flowmeter is 0.r, SCFH.
Also,.there is a continuous supply _ o f-PP air to ther,e seals.
When either personnel
!800715 0Y7A
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. Commonwealth Edison Mr. Harold R. Denton, Director July 7, 1980 Page 2 lock. door is opened, the high flow alarm will annunciate.
After the door is closea, the seals will repressurize to 3 psig and the-high flow alarm will reset within 30 seconds.
With regard to 'eference (c), the following additional R
information is being supplied to supplement the request for exemption of-the. valves listed below from the requirement for Type C leakage rate testing.
1.
Valve A0V-CC9437:
This containment isolation valve on the component cooling water 1 return'line from the excess letdown heat exhanger isolates a closed system within the containment.
The closed system does not communicate directly with the reactor coolant system (RCS) pressure boundary or the containment atmosphere.
A portion of the system piping and equipment is inside the missile barrier and a portion is outside the missile barrier.
The outside portion is missile protected by the barrier and the inside portion is also shielded from missiles because of its enclosure within' concrete walls as can be seen on the attached drawings, M-128 and M-137.
As indicated in Reference (c), the component cooling water system pressure of 100 psig is well above the containment post accident peak pressure of 47 psig, and thus any leakage past valve A0V-CC9437 and a ruptured component cooling line-would be into the containment and not out.
Therefore, no safety-implications are involved.
Since the valve is normally in the closed position, no provisions for leak testing are provided, nor required for the above reasons.
2.
Valve'A0V-RC8033:
This containment isolation vhlve on the nitrogen supply line_to'the pressurizer relief tank isolates a closed system within the containment.
The closed system does not communicate directly with the RCS pressore boundary since the pressurizer safetyLand relief valves constitute the RCS pressure boundary as demonstrated by the system design classification change downstream of these valves, nor does it communicate directly with the containment atmosphere.
The system piping and equipment is located outside the missile barrier and is therefore missile. protected..As indicated in Reference (c), the nitrogen system pressure of 100 psig on the line to the PRT (pressurizer _ relief tank) is well above the post accident containment peak pressure of 47 psig, and thus any leakage past valve A0V-RC8033 would be into the' containment and not out.
Therefore, no-safety implications are involved.
Since the valve is-normally in the closed position, no provisions for leak J
-testing are provided, nor required for the above reasons.
I
)
_a
Commonwe:lth Edison Mr. Harold ~R..Denton, Director July'7, 1980
.Page 3
-3.
Valve A0V-S18880:
This containment isolation valve on the nitrogen supply line to the' safety injection accumulators isolates a closed system within the containment.
The closed system does not f-communicate directly with the RCS pressure boundary since the accumulator discharge-line check valves constitute the'RCS pressure boundary as demonstrated by the system design classification change downstream of these check valves, nor does it communicate directly with the containment atmosphere.
The system piping and equipment is located outside the missile barrier and is therefore missile protected.
As indicated in Reference (c), the nitrogen system pressure of 600 psig on the L11ne to the SI (safety injection) accumulators is well above the post accident contalment peak pressure of 47 psig, and thus any leakage.past valve A0V-SI8880 would be into the containment and not out.
Therefore, no safety implications are involved.
Since the valve is normally in the closed position, no provisions for leak testing are provided, nor required for the above reasons.
4 Valve FCV-FP08:
This containment isolation valve on the fire protection supply header iso'lates a closed system within the containment.
The closed system does not communicate directly with the RCS pressure boundary or the containment atmosphere.
The system piping and equipment is located outside the missile barrier and is therefore missile protected as can be seen on the attached drawings M-130, 132, 133, 141, 143, 144 and 146.
As indicated in Reference (c), this valve is in a closed position.
Any leakage past valve FCV-FP08 would be into the containment and not out since the fire protection header pressure of 100 psig is well above the containment post accident peak pressure.
T.herefore, no safety implications are involved.
Since the valve is not open to containment atmosphere, no provisions for leak testing are provided, nor required for the above reasons.
5.
Valves MOV-RH8701 and MOV-RH8702:
The requirement for leakage testing of these inboard RHR
-pump suction line containment isolation valves is of little valueLand' leakage is'of no consequence.
The RHR system is
-designed to operate during containment isolation and will take suction from the containment sumps during the recirculation
_ phase.
The water quality will be essentially the same as any l potential valve leakage.
Any leakage will either be contained within the RHR system or returned to the containment in the process.
As indicated in Reference (c), these valves which are designed.to handie LOCA fluid are on the RHR pump suction line and would normally be closed and filled with water under
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' Commonwealth Edison -
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Mr.: Harold R. Denton, Director-July 17,:1980 Pagel4 post accident conditions._LAny leakage past these valves, which are in series as containment isolation valves, would be returned
.to the RHR' pump suction,fand could remain within the closed RHR system.
To' leak test these valves-would require taking both RHR
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pump systems out?of service for several hours while the unit is Ishutdown, -a maneuver which Commonwealth Edison does not consider
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prudent with regard to-safety.
Please address any additional questions that you might have
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concerning this matter to this office ~.
One (1) signed original and thirty-nine (39) copies of this letter and one marked set of-drawing are provided for your use.
Very truly yours, 5a/
t William F. Naughton Nuclear Licensing Administrator.
Pressurized Water Reactors
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