ML17328A685
| ML17328A685 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 04/26/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17328A684 | List: |
| References | |
| NUDOCS 9005020246 | |
| Download: ML17328A685 (13) | |
Text
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UNITED STATES NUCLEAR R EG ULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EYALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION INDIANA MICHIGAN POWER COMPANY DONALD C.
COOK NUCLEAR PLANT UNITS NOS.
1 AND 2 DOCKETS NOS. 50-315 AND 50-316
1.0 INTRODUCTION
On February 17, 1981, the fire protection rule for nuclear power plants, 10 CFR 50.48 and Appendix R to 10 CFR 50 became effective.
This rule required all plants licensed prior to January 1, 1979, to submit by March 19, 1981:
(1) plans and schedules for meeting the applicable requirements of Appendix R, (2) a design description of any modifications proposed to provide alternative safe shutdown capability pursuant to Section III.G.3 of Appendix R and (3) exemption requests for which the tolling provisions of Section 50.48(c)(6) were to be invoked.
By letter dated March 27, 1981, IMPC indicated that modifications were not required to provide alternative safe shutdown capability for D. C. Cook units 1
and 2.
An NRC inspection of the plants identified a number of concerns with the safe shutdown capability.
Subsequent to the inspection, IMPC, by letter dated March 31, 1983, submitted the results of it's reassessment of the safe shutdown capability to the requirements of Section III.G of Appendix R and a description of proposed modifications to provide alternative shutdown capability.
Additional information was provided by a letter dated August 22, 1983.
On November 22, 1983, the staff issued a safety evaluation on IMPC's reassessment of post-fire alternate safe shutdown capability for D. C. Cook.
The safety evaluation concluded that the alternate shutdown capability proposed for D. C.
Cook complies with the requirements of Section III.G and III.L of Appendix R.
Because of the degree of reliance on procedures for post fire safe shutdown at D. C. Cook, the staff requested IMPC to submit for NRC review (1) the most recent post fire safe shutdown procedures and (2) the proposed Technical Specifications for alternate safe shutdown capability.
By letter dated June 6, 1986, IMPC provided the procedures for post-fire remote emergency shutdown outside the control room.
The staff and its consultant from Brookhaven National Laboratory (BNL) conducted a review and walkdown of the emergency remote shutdown and associated repair procedures at D. C.
Cook during October 27-29, 1986.
Based on this review the staff issued a Safety Evaluation on January 28, 1987.
Although the Safety Evaluation identified procedural steps that required revision or amplification to provide additional guidance to the operators, it concluded that the procedures were generally workable.
9005020246 900426 PDR AXIOCK 050003iS P
PDC By letter dated Hay 30, 1986 IHPC submitted proposed technical specifications for alternate safe shutdown.
This application was further clarified and revised in submittals dated June 23, 1986, February 25, Harch 2, and June 16,
- 1988, and January 23, 1989.
The staff issued technical specifications for post fire safe shutdown on February 9, 1990.
IHPC submitted a revised report on safe shutdown capability by letters dated February 12 and Harch 20, 1987.
In their Harch 20, 1987 letter, IflPC requested that the basis of the pending NRC audit (summer of 87) be the final version of Revision I to the Safe Shutdown Capability Assessment (SSCA) rather than the Harch 1983 submittal.
Included with this information were revised exemption requests from the requirements of Section III.G of Appendix R to 10 CFR 50 and numerous fire hazards analyses which purport to justify non-fire rated features in plant fire barriers.
On July 7-17 and September 15, 1987, Region III conducted an audit of the technical status of outstanding fire protection and safe shutdown procedure issues.
As part of this audit, an inspector performed a followup review of those steps identified as requiring "revision or amplification" in the January 28, 1987, safety evaluation.
Although some of the concerns raised during the October 1986 audit were determined to have been satisfactorily
- resolved, several concerns related to safe shutdown procedures remained open.
By letter dated September 14, 1989, the staff requested clarification on several issues where IHPC's approach in their February 12, 1987, submittal was not in conformance with the staff 's guidelines (i.e.,
10 CFR 50 Appendix R, and Generic Letters 81-12 and 86-10).
The September 14, 1989, letter also requested that a
meeting be arranged at the Cook site to discuss open fire protection issues in detail.
On November 1-2, 1989, representatives of the staff met with IHPC staff at the Cook site to discuss, in detail, remaining staff concerns.
IHPC responded to these issues by letter dated February 21, 1990.
Section 2.0 documents the staff's evaluation of IHPC's response.
- 2. 0 ENLUATION
2.1.1 Issue
Appendix A (to BTP APCSB 9.5-1) Barriers.
The staff was concerned that as a
result of the IHPC's revised safe shutdown methodology, fire barr iers required by Section F of Appendix A would no longer be maintained and subject to surveillance under the provisions of the technical specifications (or plant procedures if tech specs are removed).
2~1. 2 2
IHPC responded in the February 20, 1990 that Appendix A barriers will be retained and that they, along with Appendix R barriers, will be encompassed by the technical specifications.
This issue will be addressed separately upon receipt of a Technical Specification (TS) amendment application or documentation of plant procedures providing an equivalent degree of protection.
The staff requests that IHPC respond to this open item by August 1, 1990.
2.1.3 Status
This issue is open pending submittal and approval of TS for Appendix A fire barriers.
2.2.1 Issue
NFPA Code Conformance.
The staff was concerned that fire protection features in the plant (sprinkler systems, detection
- systems, etc.) were not designed and installed in accordance with the applicable NFPA codes.
~2. 2. 2 This issue was raised with IMPC in a meeting at the plant on November 1
E 2, 1989.
IMPC responded that a code conformance appraisal had been performed but only for areas containing safe shutdown systems.
The staff responded that it would be necessary for IMPC to extend this review to all safety related areas of the plant.
The staff suggested that IMPC take the results from the initial review and focus the followup review on those areas where significant deficiencies were identified.
The staff also indicated that the results of this review would have to be evaluated and reflected in a safety evaluation.
2.2.3 Status
This issue is open pending submission of the results of IHPC's NFPA code review to the staff for evaluation.
2.3.1 Issue
Fire alarm system circuit supervision.
The staff was concerned that all circuits (including fire suppression system trip actuating circuits) were not electrically supervised in accordance with NFPA standard 72D.
~2.3.2 2
IMPC responded in the Novembe~
1989 meeting that all circuits were supervised in accordance with the referenced code with the exception of two circuits within the control room to the annunciator panels on the main control board.
The viability of these unsuperv'ised circuits is confirmed in conjunction with tests of the local alarm panels.
Written confirmation of this should be contained in the NFPA code conformance review.,
During the discussions of this issue the staff inquired if the alarm system had a "reflash" capability.
IMPC responded that although this capability did not at that time exist, a reflash capability would be installed by December, 1991.
On the basis that all but two circuits are electrically supervised in accordance with NFPA 72D and those two circuits are regularly tested to confirm operability the staff considers this issue resolved.
2.3.3 Status
Closed
Actuating sequence for Carbon Dioxide system.
The existing carbon dioxide systems discharge upon the actuation of a ~sin 1e fire detection system zone.
The staff was concerned that this would pose a risk to plant operators.
~2.2.2 R
INPC responded in the November 1989 meeting that the systems are isolated prior to human entry.
Because this procedure would prevent inadvertent actuation during occupancy of the protected
- area, the staff considers this response acceptable.
2.4.3 Status
Closed
2.5.1 Issue
Single Failure Potential for the fire water distribution system.
IMPC's 1987 report indicates that water to both automatic sprinkler systems and standpipe systems are fed from a "common supply header."
The staff was concerned that a
single break in the piping or inadvertently closed valve could render both systems inoperable.
~2.2.2 R <<
IVPC responded at the November 1989 meeting that these single failure points had all been identified and that a plant modification had been approved which would install additional isolation valves such that breaks in water supply piping could be isolated to enable any affected area to be reached by a fire hose deployed from an operable standpipe outlet or outside hydrant with not more than 200 feet of hose.
Il)PC has confirmed that an adequate quantity of water at sufficient pressure would be available.
Because this modification would effectively mitigate any potential break in the fire water supply piping, the staff considers this issue resolved.
2.5.3 Status
Closed
2.6.1 Issue
Supervision of Pre-action fire sprinkler system piping.
The staff was concerned that piping for the pre-action-type automatic sprinkler systems were not supervised such that a pipe break would cause a trouble alarm to register on the fire alarm system.
2~2.2 R
IYiPC responded in the November 1989 meeting that only the systems in the Auxiliary Drumming and Cask Handling areas were unsupervised.
In the February 21, 1990 letter, IttPC committed to provide supervision for the system in the Aux. Drumming area by September, 1990.
In the Cask Handling area the piping is high up in the ceiling and is not prone to mechanical damage.
Therefore, no supervisory capability is deemed necessary.
2.6.3 Status
Closed
2.7.1 Issue
Partial Automatic Fire Detection and Suppression Systems.
The staff requested information as to whether IflPC had justified, by internal analysis, the existence of automatic sprinkler systems and detection systems that did not provide
~corn lete protection for an individual fire area.
IHPC responded in the November
'89 meeting that fire hazards
- analyses, performed
-in accordance with the guidelines in Generic Letter 86-10, were performed for such conditions ard were kept on file in an auditable form.
These internal analyses will be subject to future staff inspections.
2.7.3 Status
Closed
2.8.1 Issue
Need for HVAC to support post-fire safe shutdown.
The staff noted that, except for certain electrical equipment such as the emergency diesel generators, HYAC is not identifi ed as being required to maintain the viability of safe shutdown equipment.
In Information Notice 84-09, the staff identified HVAC systems as being needed for post fire safe shutdown.
The staff requested additional information on this issue in a letter to It~PC dated September 14, 1989.
2~8.2 2
INPC provided a summary of the methodology and the results of an analysis which supports their conclusions in the February 21, 1990 letter.
However, the information was incomplete in that it did not:
- 1. Identify what plant areas were affected;
- 2. Identify what were the underlying assumptions of the analysis;
- 3. Indicate how the time-temperature curves were developed;
- 4. Provide details concerning the time period during which equipment was deemed functional without HVAC.
The staff, therefore, does not have sufficient information to confirm the validity of IHPC's analysis and conclusions regarding the need for HVAC.
The staff requests that INPC make available the above information during the upcoming fire protection audit.
2.8.3 Status
Open
2.9.1 Issue
Assumptions regarding component fire damage.
The staff requested clarification regarding which component types wer e assumed not to be capable of being damaged in a fire.
~2.2.2 R
IHPC responded in the February 21, 1990, letter by providing a comprehensive list of component types.
These included components such as heat exchangers, gate valves, check valves and others which the staff has historically iudged to be impervious to damage.
The staff, therefore, considers this response to be acceptable.
2.9.3 Status
Closed 2.10.1 Issue:
Diagnostic instrumentation.
The staff noted that in the 1987 revised safe shutdown methodology no diagnostic instrumentation was identified as being required for post fire safe shutdown.
This is contrary to information provided in Information Notice 84-09.
If1PC responded in the February 21, 1990, letter that this issue had been addressed in the original, 1983 version of the safe shutdown methodology and that the original methodology was reviewed and approved by the staff.
The staff does not challenge this fact.
Kowever, the current version of the post fire safe shutdown methodology was identified as a complete revision and should be a
stand-alone document, with all necessary information to enable the staff to confirm that the requirements of Section III.G. and III.L. of Appendix R are being met.
The issue of the comprehensiveness of the 1987 revision goes beyond the original concern about diagnostic instrumentation.
Lnti 1 the staff is assured that the D. C. Cook Fire Protection Program includes all elements identified in Generic Letter 88-12, this issue will remain unresolved.
2.10.3 Status:
Open 2.ll.l Issue:
hanual Operator Actions.
The staff noted that It1PC was taking credit for a number of manual operator actions to achieve safe shutdown.
The staff was specifically concerned that: l. operator actions were credited in the fire area 2 ff 2
f 2
2 2
ff, 22.
Rf plant condition may develop due to fire damage before operator actions are implemented in
~an fire area.
The staff requested specific information on this issue in a letter to IHPC dated September 14, 1989.
~2. 11. 2 R
IHPC's February 21, 1990, response presented the conclusions of a time and manpower study but did not support the conclusions with any detailed analysis.
This issue will receive additional scrutiny during the upcoming fire protection audit.
To support the audit, INPC should make available any detailed analyses that support their assumptions concerning manual operator actions to achieve safe shutdown.
2.]1.3 Status:
Open 2.12.1 Issue:
Hot shutdown Repairs.
The staff had two specific concerns:
- 1. that repairs for hot shutdown were being proposed, and 2. that shutdown procedures indicated that certain actions would on1y be taken after consultation with a corporate engineering support team.
The second concern focused on the potential delay associated with the consultation and the impact this delay might have on plant safety.
'~12.2 R
IHPC responded in the t(ovember 1989 meeting and in the February 21, 1990, letter that repairs were only proposed to achieve and maintain cold shutdown conditions.
~ i 2
2 <<1 2, 1
Assessment Group (IAG) would only take place after hot shutdown was achieved.,
Therefore, deliberations would not affect critical shutdown functions.
The staff considers these responses to be acceptable.
2.12.3 Status:
Closed 2.13.1 Issue:
Hot shutdown panel isolation.
The staff was concerned that a fire in the local shutdown indication panel area might result in damage to the normal shutdown capability in the control room.
~2.22.2 R.
IHPC responded in the February 21, 1990, letter that the LSI panels are redundant to each other and have the capabi lity to be repowered from the opposite, non-fire-affected unit.
Also, LSI indications are physically and electrically independent of the control room as described in the above-referenced letter.
On this basis, the staff's original concerns have been resolved.
2.13.3 Status:
Closed 2.14.1 Issue:
Unresolved exemption requests.
Based on the information presented in INPC's 1987 revised shutdown description (Table ] -1) it appeared that several areas were not in compliance with Appendix R and required exemptions.
The staff requested a status on these exemptions.
~2.14.2 R
IHPC responded in the November 1989 meeting that these areas/conditions were encompassed by exemptions previously granted by the staff in safety evaluations dated 6/16/83 and 8/27/85.
The staff concludes, therefore, that there are no pending exemptions.
2.14.3 Status:
Closed 2.15.1 Issue:
Revised combustible loadings.
The staff noted that in some areas described in the 1987 revised report the combustible loading increased significantly. The staff was concerned that the existing fire protection features in these areas may not be sufficient to mitigate the hazards associated with the increased combustible lnadings.
~2.55.2 R
This issue was discussed in the November 1989 meeting.
The revised combustible loadings reflect a new, more conservative approach to quantifying combustibles within individual areas and did not reflect additional hazards.
For example, the fire load associated with light diffusers and oil in pumps are now included.
These combustible materials had always been present in the areas.
On this basis, the staff concludes that the existing fire protection features for the affected areas remains adequate.
2.15.3 Status:
Closed 2.16.1 Issue:
Water through hatchways.
The staff requested information to confirm that water from fire hoses or sprinkler systems would not flow through hatchways and damage redundant safe shutdown systems below.
IMPC responded that this issue had been addressed in an October 16,
- 1987, submittal to the staff.
The IMPC's February 21, 1990 letter reiterated that only cabling, redundant to equipment and/or cabling 'located above a hatch, is contained in the elevation below the hatch.
IMPC therefore concluded that water impingement shou'Id have no impact on the cabling used at Cook Nuclear Plant and that water flow down through the hatches does not pose a potential impact on safe shutdown capability.
On this basis, this issue is resolved.
2.16.3 Status:
Closed 2.17.1 Issue:
Fire Protection Modifications.
The staff requested clarification that IMPC intends to complete all pending fire protection modifications in accordance with the criteria of the relevant NFPA codes and standards.
~2.22.2 R
IMPC responded in the February 21, 1990, letter that, in general, modifications are designed and installed in accordance with industry standards and manufacturer's recommendations.
However, under certain circumstances, literal conformance cannot be achieved.
At such times, engineering evaluations are performed to justify an alternate course of action.
These evaluations are kept on file for future audit.
The results of IMPC's NFPA Code conformance review will be submitted to the staff for evaluation.
2.17.3 Status:
This issue is considered open until the staff's evaluation of the NFPA code review is complete (see item 2).
2.18.1 Issue:
Common Enclosure Associated Circuits.
The staff requested clarification as to IMPC's method for preventing loss of safe shutdown capability due to fire damage to associated circuits by "common enclosure".
(see Generic Letter 81-12)
~2.22.2 R
IMPC provided responses to this issue in the November 1989, meeting and in the February 21, 1990, letter.
IMPC approach has two facets.
The first is providing coordinated circuit protection devices to assure that a fire induced fault is isolated.
The second is to provide fire barriers to limit the spread of fire along the cables themselves.
Conduit and cable penetrations of these barriers are sealed in accordance with IMPC's barrier seal program.
External seals are fire rated consistent with the rating of the barrier itself.
Internal conduit seals are provided as delineated in a letter to the staff dated October 20, 1988.
The internal seal program is consistent with the guidance provided in Appendix A to BTP APCSB 9.5-1 and is, therefore, acceptable.
The combination of fire barriers and circuit isolation to mitigate common enclosure failures is in conformance with Generic Letters 81-12 and 86-10 and is, therefore, acceptable.
The adequacy of circuit isolation will be confirmed during the upcoming Appendix R compliance inspection.
2.18.3 Status:
Closed 2.19.1 Issue:
Circuit Failure Modes.
IMPC's assumptions regarding fire induced circuit failures
( three phase cable-to-cable faults are not considered credible} are not consistent with the guidance issued in Generic Letter 86-10.
~2.12.2 R<<
IMPC responded in the February 21, 1990, letter that these assumptions were part of the original 1983 safe shutdown methodology which was reviewed and approved by the staff.
Because of this prior approval, modifications necessary to bring the plant into conformance with Section III.G. of Appendix R have been deemed by the staff to be a backfit.
Because three phase cable-to-cable faults are a low probability event the staff believes that a plant specific backfit analysis would only confirm the low safety significance of this issue.
Consequently, this issue is considered resolved.
2.19.3 Status:
Closed 2.20.1 Issue:
Fire damper testing.
The staff requested additional information concerning performance testing of certain field fabricated dampers identified in Section 9.7 of the 1987 revised safe shutdown report.
~2.2D.2 R
IMPC responded in the February 21, 1990, letter that these dampers are subjected to surveillance testing in conjunction with the plant Technical Specifications.
In addition, in response to a request by Region III inspectors in a February
- 1989, inspection, these
- dampers, as well as others installed in required fire barriers are being evaluated to determine their ability to close under air flow conditions.
2.20.3 Status:
This open item will be addressed by the inspection team during the upcoming fire protection audit.
2.21.1 I s sue:
Hatch surveillance.
The staff was concerned that hatches which form part of a required fire barrier are not subject to surveillance under the Technical Specifications.
~2.23.2 2
IHPC responded in the November 1989 meeting that the hatches are inspected daily, but not under the T.S.
This issue is similar to the Appendix A fire barrier issue previously identified (See 2.1.3).
INPC should respond to this issue by August 1, 1990.
2.21.3 Status:
Open 2.22.1 Issue:
Hatch integrity.
The staff requested information as to what evidence existed that hatchways in rooms protected by a gaseous fire suppression system would not adversely impact the ability of the system to reach and maintain design concentrations.
~2.22.2 R
Il!PC responded that acceptance tests had been performed on these systems and that the test results confirm that design concentrations can be maintained, despite the presence of a hatch.
On this basis, this issue is considered resolved.
2.22.3 Status:
Closed 2.23.1 Issue:
Multiple high impedance faults.
IHPC has not performed a high impedance fault analysis in accordance with the criteria delineated in Generic Letters 81-12 and 86-10.
2~23.2 R
In the February 21, 1990, letter, It1PC presented justification for their position that multiple high impedance faults are not considered credible.
The staff will scrutinize this position during the upcoming fire protection audit.
2.23.3 Status:
Open 2.24.1 Issue:
Region III. T.I.A. concerning circuit failure modes.
By memo dated f1ay 17, 1989, the region requested clarification as to whether INPC's assumptions regarding possible damage to circuits associated with valves that are not high-low interfaces.
~2.24.2 R
IHPC's position is that multiple shorts of proper polarity are not credible for non-high-low interface circuits.
This position is consistent wsit i the guidance contained in Generic Letter 86-10 and is, therefore, acceptable.
2.24.3 Status:
Closed 2.25.1 Issue:
Region III. T. I.A. concerning Tygon tubing.
The Region expressed concern that IHPC's use of the subject tubing represented an unacceptable hazard.
~2.25.2 2
The staff reviewed the circumstances under which the tubing is utilized and concludes on the basis of the limited use and its structural characteristics that no significart hazard exists.
2.25.3 Status:
Closed
- 3. 0 CONCLUSION The staff's evaluation of IHPC's February 21, 1990, response to unresolved issues related to post-fire safe shutdown methodology is summarized in Section 2.0.
Sixteen of the twenty-five issues are considered closed.
Four of the remaining open items (8, 11, 20, and 23) will be addressed by the NRC inspection team during the upcoming fire protection audit.
Two of the open items involve incorporation of TS for Appendix A fire barriers (1) and hatch surveillances (21).
The staff requests that IfiPC respond to open items 1 arid 21 by August 1, 1990.
Items 2 and 17 will remain open pending submission of the results of INPC's NFPA code review.
It1PC has previously stated that the results of their NFPA code review would be available by mid-summer, 1990.
The last open item (10) should be resolved on a schedule negotiated with the Project Hanager.
Principal Contributor:
Conrad hcCracj:en, SPLB
e e
A L