ML20070T093
| ML20070T093 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 02/02/1983 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20070T090 | List: |
| References | |
| NUDOCS 8302080197 | |
| Download: ML20070T093 (9) | |
Text
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION APPENDIX R REVIEW
. C07.0NWEALTH EDIS0N COMPANY DRESDEN NUCLEAR POWER STATION, UNIT NOS. 2 AfiD 3 DOCKET NOS. 50-237 AND 50-249 1.0 Introduction I
By letter dated July 1,1982 the licensee requested 11 exemptions from the technical requirements of Section III.G of Appendix R to,
i 10 CFR 50.
By letter dated September 23, 1982 the licensee provided additional information.
Section III.G.2 requires that one train of cables and equipment necessary to achieve and maintain safe shutdown be maintained free of fire damage by one of the following means:
a.
Separation of cables and equipment and associated no'n gafety circuits of redundant trains by a fire barrier having a 3-hour I
rating.
Structural steel forming a part of or supporting such l
fire barriers shall be protected to provide fire resistance equivalent to that required of the barrier; b.
Separation of cables and equipment and associated non-safety circuits of redundant trains by a horizontal distance of more than 20 feet with no intervening combustibles or fire hazards.
In' addition, fire detectors and an automatic fire suppression system shall be installed in the fire area; or c.
Enclosure o~f cables and equipment and associated non-safety 3-circuits of one redundant train in a fire barrier having a
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1-hour rating.
In addition, fire detectors and an automatic fire suppression system shall be installed in fire area.
8302080197 830202 PDR ADOCK 05000237 F
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If these conditions are not met,Section III.G.3' requires alternative shutdown capability independent of the area of concern.
It also
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requires a fixed suppression system in the fire area of concern if it contains a large concentration of cables or other combustibles.
These alternative requirements are not deemed to be equivalent; however, they provide _ equivalent protection for those configurations in which they are accepted.
Because it is not possible to predict the specific conditions under which fires may occur and propagate, the design basis protective features are specified in the rule rather than the design basis fire.
Plant specific features may require protection different than the measures specified in Section III..G.
In such a case, the licensee must demonstrate, by means of a detailed fire hazards analysis, that' existing protection or existing protection in conjunction with pro-posed modifications will provide a level of safety equivalent to the technical requirements of Section III.G of Appendix R.
y In summary,Section III.G is related to fire protection features for ensuring that systems and associated circuits used to achieve and main-tain safe shutdown are free of fire damage.
Fire protection configur-ations must either meet the specific requirements of Section.III.G or an alternative fire protection configuration must be justified by a fire hazard analysis.
Our general criteria for accepting an alternative fire protection con-figuration are the following:
The alternative assures that one train of equipment necessary to actiieve hot shutdown from either the control room or emergency control stations is free of fire damage.
i The alternative assures that fire damage to at least one train of equipment necessary to achieve cold shutdown is limited such that it~can be repaired within a reasonable time (minor repairs with components stored on-site).
3 Fire retardant coatin9s are not used as fire barr'iers.
Modifications required to meet Section III.G would not enhance fire protect. ion' safety above that provided by either existing 'or proposed alternatives.
Modifications required to meet Section III.G would be detrimental to overall facility safety.
2.0 Discussion Exemptions are requested from the fixed fire suppression requirement in Section III.G.3.b of Appendix 'R' to 10 CFR 50 for fire zones for
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which alternate shutdown capability has been provided.
The equipment' locations requiring fixed suppression as defined in Section III.G.3.b for which an exemption is requested are:
s 1.
All panels located in the control room 2.
480V SWGR's 28 and 29 5.
480V MCC's 28-7 and 29-7 S.
2'50V MCC's 2A and 2B 7.
125V Distribution Panels 2A and 2B 8.
480V SWGR's 33-1 and 34-1 10.
480V SWGR's 38 and 39 11.
480V MCC's 38-7 and 39-7 12.
250V MCC's 3A and 3B 13.
125V Distribution Panels 3A and 3B A brief description of each equipment location follows:
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4 All Panels Located in the Control Room
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The Dresden Unit 2 and 3 and Dresden Unit 1 control rooms form'a combined control room that is separated from the remainder of the respective plant areas by a concrete and concrete block wall that has a 3-hour fire rating.
The floor and ceiling are of concrete construction.
The control room has a fire detection system, hose station, and fire extinguishers.
An alternative safe shutdown system is also available for the control room. The room is continuously manned and the fire load in the control room is low.
4KV SWGR's 23 and 24 This equipment is located in fire zone 8.2.6.a - turbine building mezzanine floor at elev. 538'.
This fire zone is separate from e
other fire zones by spatial separation and by a concrete floor and ceiling supported on exposed' structural steel.
The floor and ceiling have numerous penetrations for stairwells, equipment removal hatches and pipe and electrical penetrations.
The pipe and electrical pene-trations are sealed. The combustible loading in the location of the switchgear is light and consists primarily of cable insulation, l
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uniformly d'istributed.
Detection, portable fire extinguishers an'd manual' hose stations are provided in the area.
i 4KV SWGR's 23-1 and 24-1 This equipment is located in fire zone 1.1.2.3 - reactor building mezzanine floor at elevation 545'-6'.'
This fire zone is separated from the adjoining fire zones in the reactor building (Zone 1.1.2.2 -
ground floor elevation 517 feet - 0 inch and Zone 1.1.2.4 - main floor elevaton 570 feet - 0 inch) by both spatial separation and a l
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5 structural concrete floor and ceiling.
The floor and ceiling have penetrations for stairways, equipment access ways, piping penetrations, and electrical penetrations.
Fire stops are provided on all electricar penetrations.
The 4-kV switchgear 23-1 and 24-1 are separated by a partial fire wall with an open accessway through it.
The combustible loading in this zone is light and consists primarily of cable insulation.
A detection system, portable fire extinguishers, and manual hose stations are provided in the area.
480V SWGR's 28 and 29 and 250V MCC's 2A and 2B This equipment is in fire zone 1.1.2.4 reactor building main floor elev. 570'.
This fire zone is separated from the adjoining fire zones in the' reactor building (Zone 1.1.2.3 - mezzanine floor o
elevation 545 feet - 6 inches and Zone 1.1.2.5 - reactor' floor elevation 589 feet - 0 inch) by both spatial separation and a structural concrete floor and ceiling.
The floor and ceiling ~have penetrations for stairways, equipment access ways, piping penetra-tions, and electrical penetrations.
The combustible loading in j
this zone is light.
Portable fire extinguishers and manual hose l
stations are provided in. the zone.
A fire detection system is
- provided in the vicinity of the 480V switchgear.
480V MCC's 28-7 and 29-7 This equipment is located in fire zone 1.1.2.2 - reactor building
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ground floor elev. 517'-6".
This fire zone is separa'ted from the l-adjoining fire zones in the reactor building (Zone 1.1.2.1 - base-ment floor elevation 476 feet - 6 inches) by b'oth spatial separation and a structural concrete ceiling and floor.
The floor and ceiling i
6 have penetrations for stairways, equipment access ways, piping penetrations and electrical penetrationsc' Fire stops are provided for all electrical penetrations.
The combustible loading in the 2
zone is moderate, approximately 31,400 BTU /FT, and is concentrated in the vicinity of the MCC's.
Portable fire extinguishers and manual hose stations are provided in the area.
An early warning detection system is provided for the two MCC's.
125V Distribution Panels 2A and 2B and 125V Distribution Panels 3A and 3B This equipment is located in fire zone 7.0 - station battery rooms.
Both stations battery rooms are enclosed by concrete and concrete block walls which possess a 3-hour fire rating.
The floor and ceil-e ing of the rooms are constructed of concrete supported by exposed structural steel.
The combustible loading in the battery rooms consists of battery casings and cable insulation.
Portable fire extinguishers and manual hose stations are provided in the vicinity
. of the battery rooms.
Early warning detection systems are provided
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inside the battery rooms.
4KV SWGR's 33 and 34 The equipment is located in fire zone 8.2.68 - turbine building mezzanine floor, elevation 538'.
This fire zone is separate from other fire zones by spatial separation and by a concrete floor and ceiling supported on exposed structural steel.
The floor and ceil-ing have numerous penetrations for stairwells, equipment removal hatches and pipe and electrical penetrations.,The pipe and elec-trical penetrations are sealed.
The combustible loading in the zone is light.
Portable fire extinguisher detection and manual hose stations,are available in the zone.
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7 4KV SWGR's 33-1 and 34-1 This equipment is located in fire zone 1.1.1.3, reactor building mezzanine floor-ele'v. 545' - 6".
This fire zone is separated from the adjoining fire zones in the reactor building (Zone 1.1.1.2 -
ground floor elevation 517 feet - 6 inch and Zone 1.1.1.4 main floor elevation 570 feet - 0 inch) by both spatial separation and structural concrete floor and ceiling.
The floor and ceiling are penetrated by stairways, equipment access ways, piping penetrations, and electrical penetrations.
Fire stops are provided on all elec-trical penetrations.
The combustible loading in the location of the 4KV SWGR is light, and consists primarily of cable insulation.
Portable fire extinguishers and manual hose stations are provided in the zone.
An early warning automatic fire detection system is installed in the vicinity of 4-kV switchgear 33-1 and 34-1.
480V SWGR's 38 and 39 and 250V MCC's 3A and 3B e
This equipment is located in fire zone 1.1.1.4 - reactor building main floor, elev 570'.
This fire zone is separated from the djoin-ing fire zones in the reactor building zone 1.1.1.3 - mezzanine floor elevation 545 feet - 6 inches and Zone 1.1.1.5 reactor floor elevation 589 feet - 0 inch) by both spatial separation and a l
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structural concrete floor and ceiling.
The floor and ceilina have penetrations for stairways, equipment access ways, piping l
penetrations, and electrical penetrations.
Fire stops are pro-vided for all electrical penetrations.
The combustible leading i
in the zone is light.
Portable extinguishers, manual hose stations and a detection system are provided.
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480V MCC's 38-7 and 39-7
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This equipment is located in fire zone l'.1.1.2 reactor building ground floor, elev. 517'-6".
This fire zone is separated from the adjoining.two zones in the reactor building (Zone 1.1.1.1 - basement floor elevation 476 feet - 6 inches and Zone 1.1.1.3 - mezzanine floor elevation 545 feet - 6 inches) by both spatial separation and a structura1 concrete ceiling and floor.
The floor and ceiling have penetrations for stairways, equipment access ways, piping penetrations and electrical penetrations.
Fire stops are provided on all electrical penetrations. The combustible loading in the zone is light.
Portable fire extinguishers, manual hose stations, and a detection system are provide,d.
3.0 Evaluation All of the fire zones for which exemptions have been requested
.z3 represent a similar configuration, i.e. combustible loading is light, there is alternate shutdown capability, smoke detection, a'nd manual fire suppression equipment is available.
There is, therefore, reasonable assurance that a fire in any of.these areas would-be promptly detected and extinguished.
The low combust,ible loading in these areas ensures that safety related equipment in adjacent areas will~not.be threatened.
The installation of a fixed fire suppression system will not significantly increase the level of fire protection in these areas.
4.0 Conclusion Based on'our evaluation, we find that the existing fire protection in conjunction with alternate shutdown capability in the areas for which an exemption has been requested provides a level of fire pro-tection equivalent to the technical requirements of Section III.G.3 of Appendix R, and therefore, the exemptions should be granted.
9 5.0 Acknowledgement The following individual contributed to this evaluation:
R. Eberly Date: February 2, 1983
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