ML20034A047
| ML20034A047 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 04/10/1990 |
| From: | Varga S Office of Nuclear Reactor Regulation |
| To: | CONNECTICUT YANKEE ATOMIC POWER CO. |
| Shared Package | |
| ML20034A045 | List: |
| References | |
| NUDOCS 9004190225 | |
| Download: ML20034A047 (12) | |
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7590-01 UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION i
In-the Matter of
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. (CONNECTICUT YANKEE ATOMIC -
Docket No. 50-213 i
POWERCOMPANY)
(Haddam Neck Plant)
EXEMPTION I.
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The Connecticut Yankee Atomic Power Company (CYAPCO, the licensee) is the
-i holder of Facility Operating License No. DPR-61 which authorizes' operation of j
the Haddam Neck Plant. The license provides, among other things, that;the s
Haddam Neck Plant is subject to all rules, regulations and Orders'of the Commission now or hereafter in effect.
The plant is a single-unit pressurized water-reactor'at the licensee's site located in Middlesex County, Connecticut.
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On November 19, 1980 the Commission published a revised Section.10 CFR 50.48 and a new= Appendix R to 10 CFR Part 50 regarding fire protection-features-of nuclear power plants.
The revised Section 50~ 48 and Appendix R became effective on February 17, 1981.Section III of Appendix R contains 15 subsections, lettered A through 0, each of which specifies requirements for a particular aspect of the fire protection features at a nuclear power plant. More specifically the Section III.G of Appendix R requires the following:
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-i Section III.G.I.(a) of Appendix R requires that fire protection features
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be provided for structures, systems, and components important to safe shutdown, These features. shall be ~ capable of limiting fire damage so that cne train of.
systems necessary to~ achieve and maintain hot shutdown conditions from either the control room or emergency control station is free of fire damage.
Section III.G.2 of Appendix R 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 non-safety circuits c.f redundant trains by a fire barrier having a 3-hour' rating. Structural' steel.
forming'a part of or supporting.such 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 combustible or fire hazards, in addition, fire detectors and an automatic fire suppression system shall be installed in the fire area; or c.
Enclosure of. cable and equipment and associated non-safety circuits of one redundant train in a fire barrier having a 1-hour rating.
In-addition, fire detectors and an automatic fire suppression' system shall be installed in the fire area.
By letter dated October 27, 1989,.CYAPC0 requested exemptions'from the above requirements for four locations in the Haddam Neck Plant.
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By letter dated October 27, 1989 the licensee requested exemptions from
- Section III.G of Appendix R.:These exemptions-were requested based on a meeting:
t held on. August 30,'1988 on fire protection issues at the Haddam Neck Plant.. The staff noted in that' meeting that in-'at least three locations conditions existed 4
which impacted existing exemptions from Appendix R and that supplemental c-exemptions would be needed.
In addition,-the licensee. identified one additional area where an exemption is warranted. The following is a list of CYAPCO.'s exemption' requests:
1..
Auxiliary Feedwater Pump. Room. An exemption was requested-from the specific requirements of Section III.G.1~.(a) to'the extent that the motor operators for redundant auxiliary feedwater valves--in the-s auxiliary feedwater pump room-(Fire Area R-2) are vulnerable to fire damage.
2.
Men's Locker Room, Fire Area S-3 and Residual Heat Removal-(RHR) Pump Pit Area, Fire Area A-1.
In safety evaluation reports dated November 27, 1987 and November 14, 1984, the staff approved exemptions from-the technical requirements of Section III.G of Appendix:R 'to'10 CFR Part 50 in the above plant locations. The licensee has made modifications in these areas which change the physical configuration and protection of safe shutdown. cables. Therefore, the separation to cables is no longer in conformance with III.G.2 of Appendix R and exemptions were y
submitted for these two areas.
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Contair. ment Cable Vault. By letter dated November 14, 1984, the staff granted approval of an exemption in the containment cable vault area from the requi_rements of Section III.G.2.(c) of Appendix R.-
The licensee's justification for this exemption was based, in part, on their proposal to protect certain' cables in a 1-hour fire-rated cable
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wrap. This was necessary because while redundant shutdown circuits were' separated by 20 feet the intervening space contained combustible materials. The licensee now proposes-to use fire-rated cables instead
.of the 1-hour cable wrap. However, because certain redundant shutdown cables will still be separated by spatial separation with intervening combustibles, an exemption from Section III.G.2.(b)- for this area was -
requested.
The staff has reviewed the four exemption requests and has concluded that-1 an acceptable basis for granting these exemptions exists. The exemptions are discussed below.
1 ~. 0 Auxiliary Feedwater Pump Room (Fire Area R-2)
An exemption was requested from the specific requirements of Section III.G.1(a) of Appendix R to 10 CFR Part 50 for the motor operators for -
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redundant auxiliary feedwater valves in the auxiliary feedwater pump: room i
because they are vulnerable to fire damage.
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1.1 Discussion t
l Motor-operated valves (MOV) FW-MOV-35 and FW-H0V-160 are located in the L
l-auxiliary feedwater pump room. These valves are used to direct auxiliary l
feedwater flow to the steam generators along either the preferred path through the auxiliary feedwater regulating valves or along the alternate path,.directly-to the stean generators. The valves are aligned in their design hot shutdown-L position during normal plant power operations and would not be required to
. change position in the event of an Appendix R fire scenario..-
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l 1.2 Evaluation
.The technical requirements of Section III.G.I.(a) have not been satisfied-in this area because the: circuits 'and valve operators for redundant auxiliary feedwater. valves 'are not protected in a manner which precludes fire damage.
The subject valves are aligned in their desired hot shutdown position during normal plant operation. The' licensee has indicated that the design of the motor operators-for the valves is that they fail as is.
Consequently,-the staff's only concern is that a fire could damage!the circuit associated with 3
the automatic ~ operation of the valves in such a manner that a spurious signal could result in a realignment of the valve.. The licensee has performed a spurious signal analysis in accordance with the guidance issued in Generic
' Letter 81-12. The results of this analysis indicated that only a. hot short on all three phases of the circuits in proper sequence would cause a' spurious signal. The staff does not consider this a credible scenario except in the case of high-low pressure piping interfaces. Because these valves are not in a r
high-low pressure piping interface and the circuits are.in conduit, the staff l
concerns regarding spurious signals are considered resolved.
1.3 Conclusion Based on the above evaluation, the staff concludes that the existing. plant' condition achieves an equivalent. level of safety to that achieved by conformance with Section III.G.1 of the Rule. Therefore, the licensee's exemption request l
from the requirements of Section III.G.I.(a) in the auxiliary feedwater pump room (Fire Area R-2) should be granted.
t-2.0 Men's Locker Room, Fire Area S-3 l
RHR Pump Pit Area, Fire Area A-1 Exemptions were requested from the specific requirements of Section o
.III.G.2. for the above areas because the separation of the cables are not in strict conformance with Appendix R.
6-2.1 Discussion In. safety evaluation reports dated November 27, 1987 and November-14, 1984',
the staff approved exemptions from the technical requirements of Section III.G i
of Appendix R to 10 CFR Part 50. for the above plant locations. By letter dated ~
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October 27,1989, the licensee described modifications to be performed in these l
areas which change the physical-configuration and protection of' safe shutdown cables. Ccnsequently, these revised exemption reouests were submitted.
a.
Men's Locker Room With the construction of the new switchgear building, the power supply j
for Service Water Pump "D" will be moved from the old'switchgear room to the new switchgear building. Accordingly, the cable's for Pump "D" will be rerouted, and will now pass beneath the service building floor before entering the old -
duct bank. The cables will join in a new concrete junction box' located below the floor of the men's locker room.
In this junction box, a new-cable will be l
l spliced onto the existing "D" service water pump cable'and travel out to the i
intake structure in its own condudt in the duct bank. The only separation at i
this point to the intake structure will be the conduits in a concrete duct bank which.is considered a new junction box. This new route will eliminate the need to have all four service water cables in the same vertical cable chase, as i
presently configured.
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b.
- RHR Pump Pit Area The staff's approval of the original exemption in the RHR pump pit area was based on credit for a partial height wall which separated redundant shutdown cables and components, and the rerouting of redundant RHR cables to enhance i
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physical separation. At this. time, the licensee proposes.to protect one division 1
of RHR pump cables by a 3-hour fire rated cable wrap, as described in their L
October 27, 1989 letter in lieu of rerouting cables. Additional modifications include installation;of curbing at the access to the pump rooms to. mitigate the effect of a lube oil spill and potential fire, and sealing the access hatchway from operating floor, elevation 21 feet 6 inches, i
o 2.2 Evaluation I
The technical requirements of Section-III.G' of Appendix R' have not been -
met in the subject areas because the redundant cables and components have not 4
been separated-and protected in accordance with the fire protection options 4
delineated in Appendix R._
i The' staff was initially concerned that a fire of sufficient magnitude.and; intensity could develop in these areas and damage b'oth shutdown trains.
'However, the men's locka area is protected by an automatic sprinkler system If a fire were to occur, the system would actuate to both control the fire and protect the shutdown circuits in the area.
Concurrently, an alarm would be-transmitted automatically-to the control room. The plant fire brigade would be dispatched and would put.out any residual combustion with available manual-fire fighting equipment.
In the RHR pump pit area, the in-situ combustible loading is minimal.<
i The most likely fire scenario is a lobe oil spill ar.d fire. The curb at the A
entrance to the cubicle would prevent oil from spreading.beyond the immediate' c
spill area.- If ignition of the oil occurs, it would be detected in its
- initial stages by plant operators or the existing fire detection system. An 1
alarm from the detection system would be transmitted automatically to the control room. The plant fire brigade would arrive within minutes to put out the fire manually. Pending arrival of the brigade, the RHR pump cubicle walls-1
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'would shield the redundant. pumps from direct flame impingement and radiant ene rgy.. The smoke and hot gases.from a fire would collect at the ceiling, and not encompass vulnerable cables or the redundant. pump'until well after the i
arrival of the brigade. The staff, therefore, concludes that the' existing _
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-fire protection-fcatures with the proposed modifications.in these two areas is sufficient to provide reasonable assurance that at least'one shutdown division-will remain free of fire damage.
2.3 Conclusion Based on the above evaluation, the staff concludes that the licensee's alternate-fire protection configuration provides an equivalent level of fire safety to that achieved by compliance with the requirements of Appendix R.
Therefore the licensee's request for exemption from the requirements of
.Section III.G of Appendix R to 10 CFR 50 in the subject areas should be granted.
3.0 Containment Cable Vault An exemption was requested from the requirements of:Section III'.G.2(b) for the above area.
3.1 Discussion By letter dated November 14, 1984,. the: staff granted an exemption.in the
' cable vault area from the. requirements of Section III.G.2(c) of Appendix R.
Specifically, redundant shutdown circuits were separated by 20 feet but the L.
intervening space contained combustibles. ihe licensee's. justification for the original exemption was based, in part, on a proposal to protect.certain shutdown cables in a 1-hour fire-rated cable wrap.
The licensee has now proposed to=
utilize fire-rated' cables in lieu of a 1-hour cable wrap.
However, because certain redundant shutdown cables will still be separated by spatial separation
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_ ith. intervening combustibles, an exemption for the area.is required.
w Fire-rated mineral insulated (MI) cables will be used to transmit one-set h
- (trainB)ofAppendixRsafeshutdownprocessmonitoringparametersthrough.
the cable vault. This set of safe shutdown parameters will be. utilized'during cable vault fires. ~ The MI' cable has-been successfully tested in accordance with ASTM Standard E119;for a 3-hour fire rating. This MI cable has been s
.previously approved by the staff.
-The transition-from containment to the cable vault will be made via special-welded penetrations which-incorporate the fire qualified HI cable. The routing of the -cable will be such that falling debris.resulting-from a cable
-vault fire will not affect the integrity of the MI cable. The MI cable will i
be. fastened to the' cable vault surfaces using unistrut and tub'ing clips. This fastening method has been qualified as part of the MI cable fire qualification.
The transition from MI cable to organ.ic cable wil_1 take place'within a I
1-hour fire rated enclosure. This enclosure and.the ccr.duit transition to the duct bank will have a 1-hour wrap and will carry _ the Appendix _ R. Train B instrument cables from the cable vault. This enclosure and-the cable runs from a
the. duct bank to the enclosure will be fire protected to meet Appendix R,Section III.G.2.c. This enclosure and the cable runs have also been evaluated with respect to falling debris resulting from a cable vault fire andlhave been i
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determined to retain their integrity.
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.The licensee's proposal to utilize 3-hour fire-rated.MI cable in lieu of-r r
L 1-hour fire-rated cable wrap as discussed in the subject letter is considered i
an enhancer:ent over the fire protection configuration approved in our LHovember 14, 1984 safety evaluation. Since no other significant change is l.
beinn proposed at thi; time, the staff concludes that the original _ justification
.for granting the exemption for containment cable vault remains valid.
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3.3 ' Conclusion Based on the-above review, and previously granted exemptions in this 1
area, the staff concludes that the licensee's alternate fire protection configuration provides an equivalent level of safety to that achieved by compliance with Appendix R to 10 CFR Part 50. Therefore,-the licensee's request for exemption from Section III.G.2'of Appendix R to 10 CFR.50 in the~ cable
-vault'should be granted.
IV.
Pursuant to 10 CFP,50.12(a)(21, the Commission will not consider granting 1
- an exemption unless soecial circr
.nces are present.. Item (ii) of the subject regulation includes special circumstances where application of the subject regulation would'not serve the underlying purpose of the rule or is not necessary c
to achieve the underlying purpose of the rule.
5 The underlying purpose of Section III.G is to provide adequate protection f
of: redundant components of safety-related equipment by-limiting damage -in the event ~of a fire at one safety-related component location so t' hat the performance of the other safety-related component is not affected. The licensee has installed automatic fire detection and suppression systems, made modifications to control oil spills, proposes to utilize 3-hour fire-rated cables in lieu of 1-hour
. cable wrap 'and provided analysis to resolve spurious ~ signal' actuation concerns I
- l in lieu of separation of the components as prescribed by Appendix R.
As: described in the evaluation section of each exemption request, the staff has concluded
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that the existing fire protection systems provide equivalent or superior fire N
protection to that which would be provided by meeting the literal separation requirements of Section III.G of Appendix R.
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In summarl', the staff has concluded that the alternative fire protection
_provided in shpport of the exemptions meets or exceeds the fire protection which would otherwise occur if ' literal compliance with the separation require-ments'were required. Therefore, the staff concludes that "special circumstances" exist for the licensee's requested-exemptions in that imposition of the literal ~
1 requirements of the regulat_ ion in these particular circumstances is not necessary-l to achieve the underlying purposes of Appendix R to 10 CFR Part 50.
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V.
Accordingly, the Commission has determined that, pursuant to 10 CFR i
50.12(a)(2)(ii), special circumstances exist in that existing levels fire protection systems satisfy.the underlying sections of Appendix R to 10 CFR Part 50.
Further, the staff has concluded that the requested exemptions are authorized by law and will not endanger life-or property or the common defense i
and security and are otherwise in the public interest. Therefore, the Commission hereby grants the exemption requests from the requirements of Section 111.G of Appendix R to 10 CFR-Part 50 described in Section III above.
Pursuant to 10 CFR 51.32, the Commission has determined that the issuance-t' of this exemption will.have'no significant impact on the environment (55 FR 13201).
A copy of the Commission's concurrent Safety Evaluation related to this---
action and the above referenced submittal by-the licensee is available for
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i public inspection at-the Commission's Public Document Room 1717 H Street,
.N.W., Washington, D.C. and at the. local public document room located at the i
Russell Library,123 Broad Street, Middletown, Connecticut 06457.
This exemption is effective upon issuance.
4-FOR THE NUCLEAR REGULATORY COMMISSION 1) t lh IN M ev ga' r
tor-Division of-Reactor Pr jects - I/II Office of Nuclear Re c or Regulation Dated at Rockville, Maryland this April 10, 1990 r
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