ML20236D336
| ML20236D336 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 10/14/1987 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | IES UTILITIES INC., (FORMERLY IOWA ELECTRIC LIGHT |
| Shared Package | |
| ML20236D338 | List: |
| References | |
| NUDOCS 8710280149 | |
| Download: ML20236D336 (9) | |
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'a 7590-01 UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION In the Matter
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Docket No. 50-331
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IOWA ELECTRIC LIGHT AND
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POWER COMPANY
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Duane Arnold Energy Center
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EXEMPTION I.
The Iowa Electric Light and Power Company (the licensee) is the holder of Facility Operating License No. DPR-49 which authorizes operation of Duane Arnold Energy Center (DAEC/the facility).
The license provides, among other things, that the facility is subject to all rules, regulations, and Orders of the Nuclear Regulatory Commission (the Commission) now or hereafter in efcect.
The facility is a boiling water reactor located at the licensee's site in Linn County, Iowa.
II.
On November 19, 1980, the Commission published a revised Section 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.
One of the subsections, III.G, is the subject of the licensee's exemption requests.
8710280149 B71014 PDR ADOCK 05000331 F
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Section III.G.2 of Appendix R requires that one train of cables and I
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 eq'uipment and associated non-safety circuits of redundant trains by a fire barrier having a 3-hour
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Structural steel forming a part of or supporting such fire q
barriers shall be protected to provide fire resistance equivalent.to j
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.
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 l
shall be installed in the fire area.
Subsection III.G.3 of Appendix R requires that where Subsection III.G.2 cannot be met, alternative or dedicated shutdown capability should be providad.
Also, for areas where alternative or dedicated shutdown is provided, fire detection and a fixed fire suppression system shall be installed in the area, room, or zone under consideration.
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1 III.
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By letter dated September 28, 1984, the licensee requested exemptions from Subsection III.G.2 of Appendix R.
By letters dated October 31, 1984, October 21, 1986 and April 3, 1987, the licensee provided additional l
information regarding the exemption request.
In the April 3, 1987 letter, the licensee provided information relevant to the "special circumstances" finding required by revised 10 CFR 50.12(a) (see 50 FR 50764).
They combined the fire 1
zones into separate categories, described the exemption request in each category and then presented the special circumstances for each category as follows:
Fire Zones: Water tight unlabeled doors between Fire Zones 1-D and 2-B (watertight door No. 203) and 1-D and 1-A (watertight door No. 202).
Description of Exemption Request:
These doors are required to be both watertight and 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated.
Underwriters Laboratories (UL) approved the doors as 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated if gasket material is not used.
However, without the gaskets the doors are not watertight.
Although there is no known gasket material which is 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated, Iowa Electric replaced the gasket material with gaskets made of Ferratex #8201 material which is used in U. S. Naval scuttles, doors and hatches located in missile blast areas and also on fume-tight doors in fire bulkheads.
Special Circumstances of 10 CFR 50.12:
Iowa Electric believes that both special circumstances 10 CFR 50.12(a)(2)(ii) and (vi) apply to the requested exemption.
Use of Ferratex #8201 gaskets makes the doors equivalent to 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated doors and literal compliance with that rating is not necessary to achieve the underlying purpose of the rule (10 CFR 50.12(a)(2)(ii)).
Furthermore, the licensee has made a good faith effort to locate a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated gasket, but such material has not been developed (10 CFR 50.12(a)(2)(vi)).
Fire Zones:
1-C to 2-A/2-B; 1-D to 2-A/2-B; 2-A/2-B to 3-A/3-B, 3-C and 3-D; 2-D to 3-A/3-B; 3-A/3-B to 4-A/4-B; 7-E to 8-F, 8-G, 8-H and 8-J; 10-A to 11-A; 10-8 to 11-A; 10-D to 11-A; 11-A to 12-A; 16-A/16-B to 16-B/16-A; 16-F to 16-A and 16-B; 17-A/17-B to 17-B/17-A; 17-C/17-D to 17-D/17-C.
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. 7590-01 Description of Exemption Request:
Exemptions from the requirement to protect structural steel forming part of or supporting required fire l
barriers (exemption from Section III.G.2.a to 10 CFR Part 50, Appendix R) l were requested for the fire zones identified above.
l Special Circumstances of 10 CFR 50.12:
Iowa Electric has demonstrated by analysis in the referenced letter that the peak temperature of the structural steel would not exceed the critical temperature of 1100 l
degrees F when exposed to fires postulated in the DAEC Fire Hazards I
Analysis.
Therefore, protection of the structural steel is not necessary to achieve the underlying purpose of the rule (10 CFR 50.12(a)(2)(ii)).
Fire Zones:
Open hatch between 3-B and 4-8 (Fire Zone 3-B)
Description of Exemption Request:
An exemption was requested from the requirement (exemption from Section III.G.2.a to 10 CFR Part_50, Appendix R) to provide a rated fire barrier at the hatch between Fire Zones 3-8 and 4-B to separate redundant safe shutdown equipment.
Special Circumstar.ces of 10 CFR 50.12:
A rated fire barrier is not needed to achieve the underlying purpose of the rule because of the existence of deluge and partial zone suppression systems, low combustible l
loading and combustible distribution (10 CFR 50.12(a)(2)(ii)).
l Fire Zones:
1-A, 1-C, 2-D, 3-A, 3-B, 4-A, 7-A, 7-C
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Description of Exemption Requests:
Exemptions were requested for fire dampers located between Fire Zones 1-A and 1-C, 7-A and 7-C, 3-B and 4-A.
I Because of congestion and construction tolerances, the dampers cannot be
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installed totally "in accordance with the conditions of their listing and l
l the manufacturer's installation instructions" as required by NFPA 90A, l
Article 3-3.7.2.1.
l Exemptions were also requested from the requirements of Section III.G.2.a (also Section III.G.2.b for Fire Zone 1-A) of 10 CFR Part 50, Appendix R.
The exemption request proposed the use of the flexible wrap manufactured by B & B insulators under the trade name "Hemyc".
The use of the flexible "Hemyc" material provides protection equivalent to a complete 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> fire barrier.
l Special Circumstances of 10 CFR 50.12:
The ability of the fire barriers and fire dampers to function will be unimpaired by their installation.
Thus, requiring in-situ testing of the dampers to meet the literal reading l
of NFPA 90A, Article 3-3.7.2.1 is not necessary to achieve the underlying purpose of the rule.
The flexible "Hemyc" material has been shown, by extrapolation from 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> test data, to be equivalent to a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> fire barrier and its use achieves the underlying purpose of the rule (10 CFR l
50.12(a)(2)(ii)).
For Fire Zone 1-A, Iowa Electric has demonstrated that l
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exemption from full zone detection and automatic suppression is justified and requiring such is not necessary to achieve the underlying purpose of the rule (10 CFR 50.12(a)(2)(ii)).
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Based on the above information and analysis, the Commission's staff concludes that "special circumstances" exist for the licensee's requested l
exemptions.
See 10 CFR 50.12(a)(2)(ii) and (vi).
The following lists the specific exemption requests submitted by the l
licensee in their September 28, 1984 letter, supplemented by letters dated l
1 October 31, 1984 and October 21, 1986.
1.
o Reactor Building, Elevation 716 feet, 9 inches, Torus Area, Fire Zone IA.
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An exemption was requested from the specific requirements of Section III.G.2.a to the extent that it requires redundant safe l
shutdown cables and equipment be separated by a 3-hour rated fire barrier.
o Reactor Building, Elevation 757 feet, 6 inches, RHR Valve Room, Fire Zone 20.
An exemption was requested from the specific requirements of Section III.G.2.a to the extent that it requires redundant safe shutdown cables and equipment be separated by a 3-hour rated fire barrier.
o Reactor Building, Elevation 786 feet, Laydown Area and Reactor Water Cleanup (RWCU) Area, Fire Zones 3A/38.
An exemption was requested from the specific requirements of Section III.G.2.a to the extent that it requires redundant safe shutdown cables and equipment be separated by a 3-hour rated fire barrier.
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o Reactor Building, Elevation _716 feet, 9 inches, Torus Area, l
Fire Zone 1A.
j An exemption was requested from specific requirements of Section III.G.2.b to the extent that it requires automatic fire suppression and detection be installed throughout the fire area.
3.
o Door No. 202 (Between Fire Zone ID and Fire Zone 1A).
An exemption was requested from the specific requirement of j
l Section III.G.2.a to the extent that it requires redundant safe
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I shutdown cables and equipment be separated by a 3-hour rated fire barrier.
o Door No. 203 (Between Fire Zone 10 and Fire Zone 28).
An exemption was requested from the specific requirement of Section III.G.2.a to the extent that it requires redundant
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i safe shutdown cables and equipment be separated by a 3-hour j
q rated fire barrier.
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o Equipment Hatch Between Fire Zone 3B and Fire Zone 48.
An exemption was requested from the specific requirement of Section III.G.2.a to the extent that' it requires redundant safe shutdown cables and equipment be separated by a 3-hour rated
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5.
o Fire Dampers FD-010 and FD-012 (Between Fire Zone 1A and Fire Zone 1C).
An exemption was requested from the specific requirement of Section III4G.2.a to the extent that it requires redundant safe shutdown cables and equipment be separated by a 3-hour rated' fire barrier.
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o Fire Damper FD-021 (Between Fire Zone 7A'and Fire Zone'7C).
An exemption was requested from the specific requirement.of Section III.G.2.a to the extent that it requires redundant safe shutdown cables and equipment be separated by a 3-hour rated fire barrier.
o Fire Damper FD-111 (Between Fire Zone 3B and Fire Zone 4A).
An exemption was requested from the specific requir' ment of e
Section III.G.2.a to the extent that it requ' ires redundant safe shutdown cables and equipment be separated by a 3-hour rated i.
6.
o Protection of Exposed Structural Steel for Rated Barriers.
An exemption was requested from the specific requirements of.
Section III.G.2.a to the extent that it requires structural steel forming part of or supporting fire barriers be protected to provide fire resistance equivalent to that l
required of the barrier.
In summuy, the exemptions were requested for separating redundant' trains-by 3-hour rated fire barriers and for providing automatic. fire suppression and detection systems.
The exemptions for 3-hour rated fire barriers separating l
redundant trains. included valve motor operators and flexible conduit not l
protected for 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />, watertight doors, and an open equipment hatch and fire dampers not installed in the configuration as they.were fire tested.
Fire Zone 1A does not contain automatic fire suppression and detection systems throughout the zone.
Structural steel forming a part of or supporting required fire barriers in certain areas'is not protected to'a fire resistance equivalent to that of the' barriers.
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-- 8 7590-01 The licensee has provided alternative and/or acceptabl'e levels'of fire l
protection for areas'containing redundant safe shutdown systems not separated from each other.
Fire pt otection in areas with more than a negligible l
combustible load and containing safe shutdown equipment'or cables consists of fire detectors and/or automatic fire suppression systems, and portable l
i extinguishers and hose stations.
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I The Commission's staff finds that there is reasonable assurance that'a fire in these areas would be of low magnitude, promptly detected, and l
extinguished.
The low combustible loading in each area ensures that redundant.
safe shutdown equipment located in the adjoining areas will not be damaged i
before the fire brigade can extinguish the fire.
Based on the review of the licensee's analysis, the Commission's. staff concludes that the installation of 3-hour fire rated enclosures'around safe.
j shutdown valve motor operators and the installation of an automatic fire suppression and detection system throughout. Fire Zone 1A would not significantly increase the level of fire protection in these zones.
Furthermore, the identified fire dampers and doors, equipment ~ hatch, and unprotected structural steel provide a level of fire protection equivalent to the technical requirements of Section III.G of Appendix R. ' Additional' details-concerning the. exemptions are provided in the Safety Evaluation issued l
concurrently.
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. 7590-01' IV.
Accordingly,'the Commission has_ determined that, pursuant to 10 CFR 50.12(a), (1) these exemptions as described in.Section~'III:are authorized by-law, will not present an undue risk to the public health and safety, and are consistent with the common defense and security; and (2) special circumstances 10 CFR 50.12(2)(ii) and (vi) are present as discussed in III above.
Therefore, the Commission hereby grants the aforementioned' exemptions-from the requirements of Section III.G of Appendix R to 10 CFR Part 50 as-described in Section III above.
Pursuant to 10 CFR 51.32, the Commission has determined that granting these exemptions will have no significant impact on the environment (52 FR 37855).
A copy of the concurrently issued Safety Evaluation related to this action is available for 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 Cedar Rapids Public Library, 500 First Street, SE, Cedar i
Rapids, Iowa 52401.
A copy may be obtained upon written request addressed to the U.S. Nuclear Regulatory Commission, Washington, D.C. 20555, Attention:
Director, Division of Reactor Projects.- III, IV, V and Special Projects.
This Exemption is effective upon issuance.
FOR THE NUCLEAR REGULATORY COMMISSION j
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l Denni rule.le 1 rec or Division of Reactor P jects - III,.IV, V
& Special Projects Dated at Bethesda, Maryland this 14th day of October 1987 1
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