ML20079Q879
| ML20079Q879 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 12/30/1983 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20079Q741 | List: |
| References | |
| NUDOCS 8402010409 | |
| Download: ML20079Q879 (4) | |
Text
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5, UNITED STATES 7%
'i NUCLEAR REGULATORY COMMISSION 7, h '.
C WASHINGTON, D. C. 20555
% %$ fl S,..... e SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO EXEMPTION FROM 10 CFR~50, APPENDIX R ALABAMA POWER COMPANY JOSEPH M. FARLEY NUCLEAR PLANT, UNIT N05. 1 AND 2 DOCKET N05. 50-348 AND 50-364 1.0 I,ntroduction By letter dated June 18, 1982, tM licensee requested an exemption from the technical requirements of Section III.G.2 of Appendix R to 10 CFR 50 to the extent.that it requires specified fire protection measures for the protection of safe shutdown cables and equipment located inside con-tainment for both units. ' In our evaluation of these exemptions, we stated that the licensee had not provided a fire hazards analysis which compared the level of safety provided by existing arrangements to that required by Appendix R to 10 CFR 50 and, therefore, recommeded the denial of these exemptions.
By letter dated July 27,1982, the licensee provided additional information.
The licensee identified three systems that did not meet the requirements of Section III.G inside containment for which exemptions were requested.
These three systems are the pressurizer power operated relief valves and block valves, reactor vessel head vent valves and instrumentation for the pressurizer pressure and level indication.
The licensee revised the exemption request to cover only these three items inside containment.
2.0 Discussion lG.
The cabling.of the Power Operated Relief Valves (PORV) and block valves E
of both trains are not separated by a horizontal distance of more than O
20 feet free of combustibles.
The pressurizer is equipped with two g
$x parallel vent paths each having a PORV and a block valve.
The PORV's
-eg are solenoid operated valvns, are normally closed, and fail by design
{
in a closed position.
The block valves are Imotor operated valves, are k
normally open, and fail by design in an 'as-is" position.
The PORV's d
and block valves provide for reactor coolant system depressurization
. and are essential to maintain the integrity of the reactor coolant pressure boundary.
Each PORV cable is routed in a separate enclosure.
The only energized cables within the enclosures containing the PORV cables are for control room indicating lights.
If a hot short occurred between the control room indicating light cable and PORV cable, the low power of the control room indicating light cable would not be sufficient to inadvertently open-the PORV's.
Since the PORV's would remain in the closed position, inadvertan't operation of the pressurizer block valves would not be significant.
An alternate means of depressurization is provided by the pressurizer auxiliary spray.
The. auxiliary spray cabling and equipment are separated by a horizontal distance of more than 20 feet free of combustibles from either of the cabling and equipment of the redundant PORV's and block valves; consequently, the auxiliary spray would be available to provide for depressurization of the reactor coolant system and no modulation or repositioning of the PORV's or block valves is necessary.
The cabling of the reactor vessel head vent valves are not adequately separated.
The reactor vessel head vent system consists of two parallel flow paths each having two normally closed, normally de-energized valves in series that fail closed by design.
One valve in each path is required to remain closed to maintain the integrity of the reactor coolant pressure boundary.
No modulation or repositioning of the valves would be necessary to achieve a safe shutdown during a containment fire.
Each head vent valve cable is routed in a separate enclosure.
As with the PORV's, the only energized cables within the enclosures containing the head vent valve cables are associated with control room indicating lights.
If a hot short occurred between the control room indicating light cable and the head vent valve cable, the low power of the control room indicating light cable would not be sufficient to inadvertantly open the head vent valves.
At two locations in the containment, redundant trains of pressurizer level and pressure instrumentation are not separated adequately.
There is at least one channel of primary system pressure indication whose cables are horizontally separated by more than 20 fee'. free of intervening combus'tible from the cable of its redundant counter-part.
Cables of pressurizer level indication are not separated adequately.
In the fire a'reas containing the pressufizer level cables, all cable insulation is qualified to IEEE-383-1976 and protected against pro-tractive faulted conditions by overcurrent devices.
Additionally, all cables are enclosed in conduit Fire protection is provided inside containment in the form of smoke
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detection, and manual hose stations.
3.0 Evaluation The protection for redundant trains of safe shutdown equipment inside containment does not meet'the technical requirements of Section III.G because twenty-feet of separation does not exist between redundant cables free of intervening combustibles. Due to.the cables and components specific configurations and locations within the contain-ment and due to the restricted access of these sub-areas durin.g plant operations, an' exposure fire involving the accumulation of significant quantities of transient combustible materials is unlikely.
Because the cables in these sub-areas inside containment are qualified to IEEE Standard 383 and are routed in conduit, it is our opinion that a fire of sufficient magnitude to damage redundant cables or
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components is unlikely.
' 4.0 Conclusion Based on the above evaluation, the existing protection for the contain-ment area of Units 1 and 2 provides a level of fire protection equivalent to the. technical requirements of Section III.G of Appendix R.
There-
-fore. the exemptions should be granted.for the specific systems in the Cont'aihment Buil'dihg as described herein.
Dated: December.30, 1983.
Principle Contributor: R. Eberly e
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