ML20052F903
| ML20052F903 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 05/04/1982 |
| From: | Harold Denton Office of Nuclear Reactor Regulation |
| To: | PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| Shared Package | |
| ML20052F904 | List: |
| References | |
| NUDOCS 8205140126 | |
| Download: ML20052F903 (31) | |
Text
7590-01 UNITED STATES NUCLEAR REGULATORY COMMISSION In the Matter of
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PHILADELPHIA ELECTRIC COMPANY, ET AL )
Dockets Nos. 50-277 and 50-278 (Peach Boti.om Atomic Power Station,
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Units 2 and 3)
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EXEMPTION I.
The Philadelphia Electric Company (the licensee) and three other co-owners are the holders of Facility Operating Licenses Nos. DPR-44 and DPR-56 which authorize operation of the Peach Bottom Atomic Power Station', Units 2 and 3 (Peach Bottom or the facilities).
These licenses provide, among other things, that they are subject to all rules, regulations and Orders of the Nuclear Regulatory Commission (the Commission) now or hereafter in effect.
The facilities are boiling water reactors located at the licensee's site in York County, Pennsylvania.
II.
OnNovember 19, 1980, the Commission published a revised Section 10 CFR 50.48 and a new Appendix R to 10 CFR 50 regarding fire protection features of nuclear power plants (45 FR 76602).
The revised Section 50.48 and Appendix R became effective on February 17, 1981. Section 50.48(c) established the schedules for satisfying the provisions of Appendix R.
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 these 15 subsections, III.G, is the subject o' this Exemption. Subsection III.G specifies detailed requirements for fire protection of the equipment used for safe shutdown by means of separation and barriers (III.G.2).
If the requirements for separation and barriers could not G205140126 820504 PDR ADOCK 05000277 F
P8 2/3 7590-01 be met in an area, alternative safe shutdown capability, independent of that area and equipment in that area, was required (III.G.3).
Section 50.48(c) required conpletion of all modifications to meet the provisions of Appendix R within a specified time from the effective date of this fire pmtection rule, February 17, 1981, except for modifications to pro-vide alternative safe shutdown capability. These latter modifications (III.G.3) require NRC review and approval. Hence, Section 50.48(c) requires their completion within a c.ertain time after NRC approval. The date for submittal of design descriptions of any modifications to pmvide alternative safe shut-down capability was specified as March 19, 1981.
Philadelphia By letter dated March 20, 1981, as amended February 18, 1982 6 Electric Company requested exemptions from 10 CFR 50.48(c) with respect to the requirements of Section III.G of Appendix R as follows:
(1) Extend fmm March 19, 1981, to June 30, 1982, the date for submittal of plans and schedules to achieve compliance with III.G.2 required by 5 50.48(c)(5);
(2) Extend from March 19, 1981, to June 30, 1982, the date for filing addi-tional exemptions from Section III.G pursuant to 650.12(a) and 50.48(c)(6);
(3) Extend from March 19, 1981, to June 30, 1982, the date fo'r submittal of design descriptions of alternative or dedicated shutdown systems to comply with Section III.G.3, if such are necessary; and (4) Extend from February 17, 1981, to June 30, 1982, the date from which the installation schedules established in 650.48(c)(2) and (3) are calculated.
When this fire protection rule was approved by the Commission, it was understood that tL time required for each licensee to reexamine those pre-viously-approved configurations at its plant to deter nine whether they meet the requirements of Section III.G of Appendix R to 10 CFR 50 was not well known and would vary depending upon the degree of confomance. For each item of nonconformance that was found, a fire hazards analysis had to be performed to
PB 2/3 7590-01 detemine whether the existing configuration provided sufficient fire pro-tection.
If it did, a basis had to be formulated for an exemption request.
If it did not, modifications to either meet the requirements of Appendix R or to provide some other acceptable configuration, that could be justified for an exemption, had to be designed. Where the fire protection features alone could not ensure protection of safe shutdown capability, alternative safe shutdown capability had to be designed as required by Section III.G.3 of Appendix R.
Depending upon the extensiveness and number of'the areas involved, the time required for this reexamination, reanalysis and redesign could vary from a few months to a year or more. The Commission decided, however, to require one, short-term date for all licensees in the interest of ensuring a best-effort, expedited completion of compliance with the fire protection rule, recognizing that there would be a number of licensees who could not meet these time restrairts but who could then request appropriate relief throl;gh the exemption process.
Licensees for 44 of the 72 plants to which Appendix R applies (plants with an operating license issued prior to January 1,1979) have requested such schedular relief.
The licensees for the remaining 28 plants made submittals to meet the schedular requirements of 50.48(c). All of these submittals, however, were deficient in some respects.
In general, much of the infomation requested in a generic letter (81-12) dated February 20, 1981, to the licensees of all 72 plants, was not provided. Therefore, additional time is being used to conplete those submittals also.
III.
Prior to the issuance of Appendix R, the Peach Bottom Units had been reviewed against the criteria of Appendix A to the Branch Technical Position
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l PB 2/3 7590-01 9.5-1 (BTP 9.5-1).
The BTP 9.5-1 was developed to resolve the lessons learned from the fire at Browns Ferry Nuclear Plent.
It is broader in scope than Appendix R, formed the nucleus of the criteria developed further in Appendix R and in its present, revised form constitutes the section of the Standard Review Plan used for the review of applications for construction permits and operating licenses of new plants. The review was completed by the NRC staff and its fire protection consultants and a Fire Protection Safety Evaluation (FPSER) ws: issued with License Amendments Nos. 53 dated May 23, 1979. A few items remained unresolved.
Further discourse between the licensee and the NRC staff resulted in resolution of these items as l
documented in four supplements to the FPSER. The FPSER and its supplements supported the issuance of amendments to the operating licenses of the Peach Bottom Units which required modifications to be made to plant physical features, systens, and administrative controls to meet the criteria of Appendix A to BTP 9.5-1.
All of these modifications have been completed. Therefore, the Peach Bottom Units have been upgraded to a high degree of fire protection already and the extensive reassessment involved in the request for additional time is to quantify, in detail, the differences between what was recently approved and the specific requiraments of Section III.G to Appendix R of l
I each Bottom Units 2 and 3 - FPSER Supplements P
No. 1 - August 14, 1980 No. 2 - September 15, 1980 No. 3 - October 10, 1980 No. 4 - November 24, 1980
PB 2/3 7590-01 Based on the above considerations, we find that the licensee has cons pleted a substantial part of the fire protection features at Peach Bottom Units 2 and 3 in conformance with the requirenents of the fire protection rule and is applying significant effort to complete the reassessment of any remaining modifications which might be necessary for strict conformance with Section III.G. We find that because of the already-completed upgrading Lf these facilities, there is no undue risk to the health and safety of the public involved with continued operation until the completion of this reassessment on June 30, 1982. Therefore, an exemption should be granted to allow such time for completion. However, becadse we have found that most submittals of this reanalysis to date from other licensees have not been complete; that is, not all of the information requested by generic letter 81-12 dated February 20, 1981, was provided, we are adding a condition to this Liemption that requires all such infor: nation to be submitted by the date granted.
IV.
w-Accordingly, the Commission has determined that, pursuant to 10 CFR 50.12, t
an exemption is authorized by law and will not endanger life or property or l
the common defense and security and is otherwise in the public interest and
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PB 2/3 7590-01 hereby grants the following exemptions with respect to the requirements of Section III.G of Appendix R to 10 CFR 50:
(1)
The date, March 19, 1981, for submittal of achieve compliance as required by 650.48(c) plans and schedules to (5) is extended to June 30, 1982; (2) The date, March 19, 1981, for filing exemption requests pursuant to 550.48(c)(6) which includes a tolling provision is extended to June 30, 1982; (3) The date, March 19, 1981, for submittal of design descriptions of alterna-tive or dedicated shutdown systems to comply with Section III.G.3 as required by 550.48(c)(5) is extended to June 30,1982; and (4) The date, Februa y 17, 1981, from which the installation schedules established in 5:i0,48(c)(2) and (3) are calculated, is extended to June 30, 1982; Provided the following conditions are met:
- 1) Requests for exemption pursuant to 150.48(c) must include:
a) A concise statement of the extent of the exemption; b) A concise description of the proposed alternative design features related to assuring post-fire shutdown capability; and c) A sound technical basis that justifies the proposed alternative in terms of protection afforded to post-fire shutdown capability, degree of enhancement in fire safety by full compliance with III.G requirements, or the detriment to plant safety incurred by full compliance with III.G.
A simple statement that the feature for which the exemption is requested was previously approved by the NRC staff is not sufficient. A simple assertion that in the licensee's judgment the feature for which the exemption is requested is adequate fire protection is not sufficient.
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- 2) The design descriptions of alternative or dedicated shutdown systems i
to comply with Section III.G.3, as required by 550.48(c)(5) shall include a point-by-point response to each item in Section 8 of to generic letter 81-12 dated February 20,1981, and to each item in Enclosure 2 to generic letter 81-12,' dated February 20, 1981.
l If the licensee does s.at meet the above conditions, the licensee will be found in violation of 10 CFR 50.48(c) even though the submittal may be made within the time limit granted by the Exemption.
If such a violation occurs, imposition of a civil penalty will be considered under Section 234 of the Atomic Energy Act, as amended. Such a violation will be a continuing one i
PB 2/3 7590-01 beginning with the date set in the Exenption for submittal and terminating when all inadequacies are corrected.
A delay in the determination of inadequacy by the NRC staff, caused by the workload associated with reviewing all of the submittals falling due near the same time, will not relieve the licensee of the responsibility for completeness of the submittal, nor will such delay cause any penalty that may be imposed to be mitigated.
The NRC staff has determined that the granting of this Exemption will not result in any significant environmental impact and that pursuant to 10 CFR 51.5(d)(4) an environmental impact statement or negative declaration and environmental impact appraisal need not be prepared in connection with this action.
FOR THE NUCLEAR REGULATORY COMMISSION k$
Harold R. Denton, Director Office of Nuclear Reactor Regulation Dated at Bethesda, Maryland this 4th day of May 1982.
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.i Enclosur'e 2 CLARIFICATION OF GEllERIC LETTER On February 20, 1981, generic letter 81-12 was forwarded to all reactor licensees with plants licensed prior to January 1, 1979. The letter restated the require-ment of Section 50.48 to 10 CFR Part 50 that each licensee would be required to reassess areas of the plant where cables or equipment including associated non-safety circuits of redundant trains of systems necessary to achieve and maintain hot shutdown conditions are located to determine whether the require-mer.ts of Section III~.~G.2 of Appendix R to 10 CFR 50 were satisfied. Additionally, and Enclosure 2 of'the generic letter requested additional infomation concerning those areas of the plant requiring alternative shutdown-
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capability. Section 8 of Enclosure 1 requested infomation for the systems, equipment and procedures of alternative shutdown capability and Enclosure 2 defined associated circuits and requested information concerning associated circuits for those areas requiring alternative shutdown.
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In our review of licensee submittals and mee' tings with licensees, it has become apparent that the request for information should be clarified since a lack of clarity'could result in the submission of either insufficient or e,xcessive l
infomation. Thus, the staff has rewritten Section 8 of Enclosure 1 and
' of the February 20, 1981 generic letter. Additionally, further clarification of the definition of associated circuits has been provided to l
l aid in the reassessments to detemine compliance with the requirements of Sections III.G.2 and III.G.3 of Appendix R.
In developing this= rewrite we have considered the-coment of the Nuclear Utility Fire Protection Group.
The attached rewrite of the Enclosures contains no new requirements but merely attempts
' to clarify the request for additional infomation.
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2-Licensees who have not responded to the February 20, 1981 generic letter,
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may choose to respond to the enclosed request for information. Since the enclosed request for information is not new, but merely clarification of our previous letter, responding to it should not delay any submittals in progress that are based upon February 20, 1981 letter.
Licensees whose response to the February 20, 1981 letter, has been found incomplete resulting in staff identificatiohs of a major unresolved item (ise., associated circuits),
may choose to respond to pertinent sections of the enclosed request-for infor-mation in order to close open items (i.e., open item for. assoc'iated circuits-use rewrite of Enclosure 2).
If additional clarification is needed, please contact the staff Project flanager for your plant.
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ATTACHf1ENT 1 TO EllCLOSURE 2 1
REWRITE OF SECTION 8 REQUEST FOR ADDITIONAL IfiFORMATION The following is a rewrite of the staff's request for additional _ ir. formation concerning design modification to meet the requirements of Section III.G.3 of
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Aripendix P..
The follouing contains no new requests but is merely a rewording of Section 8 of Enclosure 1 of the February 20,'1981 generic letter.
1.
Identify those areas of the plant that will not meet the requirements of
%ction III.G.2 of Appendix R and, thus alternative shutdown will be provide'dx or an exemption _from the requirements of Section III.G.2 of Appendix R will be provided. Additionally provide a statecent that all other areas of the plant are or will be in compliance with Section III.G.2 of Appendix R.
For each of those fire areas of the, plant requiring an alternative shutdown systen(s) provide a complete set of. responses to the following requests for each fire area:
a.
List the system (s) or portions thereof used to provide the shutdown capability with the loss of offsite power.
b.
For those systems identified in "la" for which alternative or dedicated shutdown capability must be provided, list the equip'ent and components m
of the normal shutdown system in the fire area and identiff the functions of the circuits of the normal shutdown system in the fire area (power to what equipment, control of what components and instrumentation). Describe the system (s) or portions thereof used to provide the alternative shutdown l
capability for the fire area and provide a table that lists the equipment and components of the alternative shut'down system for the fire area.
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For each alternative system identify the function of the new circuits being provided.
Identify the location (fire zone) of the alternative shutdown equipment and/or. circuits that bypass the fire area and verify that the alternative shutdown equipment and/or circuits are separated from the fire area in accordance with Section III.G.2.
c.
Provide drawings of the alternative shutdown system (s) which highlight any connections to the normal sh' tdown systems (P& ids for piping ana components, u
elementary wiring diagrams of electrical cabling).
Show the electrical location of all breakers for power cables, and isolation devices for control and instrumentation circuits for the alternative shutdown systems for that fire area.
d.
Verify that changes 'to safety systems will not degrade saft.ty systems; (e.g., new isolation switches and control switches should meet design criteria and standards in the FS." for electrical' equipment in' the system that the switch is to be installed; cabinets that the switches are to be mounted in should also meet the same criteria (FSAR) as other safety related cabinets and panels; to avoid inadvertent isolation from the control room, the isolation switches should be keylocked or alamed in the control room if in the." local" or " isolated" position; periodic checks should be made to verify that the switch is in the proper position for normal operation; and a single transfer switch or other new device should not be a source of a failure which causes loss of reounaant soft:ty *.
f systems).
e Verify that licensee procedures have been or will, be develo' ped which describe the tasks to be perfomed to effect the shutdown method.
Provide a summary of these procedures outlining operator actions.
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Verify that the manpower required to perform the shutdown functions using the procedures of es as well as to provide fire brigade members to fight the fire is available as required by the fire brigade technical speci.
fications.
9 Provide a commitment to perform adequate acceptance tests of the alter-native shutdown capability.
These tests should verify that:
equipment operates from the local control station when the transfer or isolation switch is placed in the " local" position and that the equipment cannot be operated from the control room; and that equipment operates from the.
control room but cannot be operated at the local control station when the transfer isolation switch i's in the " remote" position.
h.
Provide Technical Specifications of the surveillance requirements and limiting conditions for 9peration for that equipment not already covered by existing Technical Specifications.
For example, if n'ew isolation and control switches are added to a shutdown system, the ' existing Technical Specification surveillance requirements should i.
be supplemented to verify system / equipment functions from the alternate shutdown station at testing intervals consistcrt with the guidelines of Regulatory Guide 1.22 and IEEE 338.
Credit may be taken for other existing tests using group overlap test concepts.
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For new equipment comprising the alternative shutdown capability, verify that the systems available are adequate to perform t'he necessary shut-down function. The fuhetions required should be based on previous analyses, if possible (e.g., in the FSAR), such as a loss of nonnal ac power or shutdown on Group 1 isola, tion (BWR).
The equipment required for the alternative capability should be the same or equivalent to that relied on in the above analysis.
j Verify. that repair procedures for cold shutdown systems are developed and material for repairs is maintained on site.
Provide a summary of these procedures and a$ list of the material needed for repairs.
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ATTACHMEllT 2 TDTilCLD5WE 2---
SAFE SHUTDOWN CAPABILITY The following discusses the requirements for. protecting redundant and/or alternative equipment needed for safe shutdown in the event of a fire. The requirements of Appendix R address hot shutdown equipment which must be free of fire damage.
The followt.ng r.equirements also apply to cold s,hutdown equipnent 1f the. licensee elects to demonstrate that tiie.equipaent.is to be free of. fir _e. damage.
AppendE R does allow.rejairable damage to cold shutdown eautoment.
Us'ing the requiremsnts of Sections III.G and III.L of Appendix R, the cdpa '
bility'to achieve hot shutdown must exist given a fire in any area of the plant in conjunction with a loss of offsite power for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
Section III.G of Appendix R provides four methods for ensuring that the hot shutdown capa-bility is protected from fires.
The first three options as defined in Section III.G.2 provides methods for protection from fires of equipment needed for hot shutdown:
1.
Redundant systems including cables, equipment, and associated circuits may be separated by a three-hour fire Iated barrier; or,
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2.
Redundant systems. including cables, equipment and associated circuits may l
be separated by a horizontal distance of more than 20 feet with no inter-vening combustibles.
In addition, fire detection and an automatic fire suppression system are required; or, 3.
Redundant systems including cables, equipment and associated circuits may by enclosed by a one-hour fire rated ba,rrier.
In addition, fire detectors and an automatic fire suppression system are required.
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. The last option as defined by Section III.G.3 provides an alternative shutdown capability to the redundant trains damaged by a fire.
4.
Alternative shutdown equipment must be independent of the cables, equip-ment and associated circuits of the redundant systems damaged by the fire.
Associated Circuits of Concern The following discussion provides A) a definition of associated circuits for Appendix R consid6~ ration, B) the guidelines for protecting the safe' shutdown capability from the fire induced failures of associated circuits and C) the in-
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formation required by the staff to review associated circuits. The definition
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of associated circuits has not changed from the February 20, 1981 generic letter; but is merely clarified.
It is important to note that our interest is only with those circuit (cables) whose fire-induced failure could effect shutdown.
The guidelines for protecting the safe shutdown capability from the fire-induced failures of associated circuits are not requirements. These guidelines should be used only as guidaned when needed. These guidelines do not limit the ' alter-natives available to the licensee for' protecting the shutdown capability.
All proposed methods for protection of the shutdown capability from fire-induced i
failures will be evaluated by the staff for acceptability..,.
A.
Our concern is that circuits within the fire area will, receive fire damage yhichcanaffectshutdowncapabilitya'ndtherebypreventpost-firesafe shutdown. Associated Circuits
- of Concern are defined as those cables e
(safety N1ated, non-safety related, Class 1E, and non-Class lE) that:
- The definition for associated circuits is not exactly the same as the definition presented in IEEE-384-l'977.
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Have a physical separation less than that required by Section III.G.2 of Append'ix R,.and; 2.
Have one of the following:.
a common power source with the shutdown equipment (redundant or
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a.
alternative) and the power source is not electrically protected frem the circuit of concerp by coordinated breakers, fuses, or similar devices (see diagram 2a), or b.
a connection to circuits of equipment whose spurious operation would adversely affect.the shutdown capability (e.g., RHR/RCS
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isolation valves, ADS valves, PORVs, steam generator atmospheric dumpvalves, instrumentation,steambypass,etc.)(seediagram2b),or a common enclosure (e.g., raceway, panel, junction) with the shutdown c.
cables (redundant and alternative) and.
(1) are not electrically protected,by circuit breakers, fuses or simi-
- lar devices, or (2)will allow propagation of the fire into the common enclosure, (see diagram 2c).
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EXAMPLES OF ASSOCIATED CIRCUITS OF CONCERN L
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{^(n, B-bus Epp,,,e,d-a,e spadeus The area barriers shown above mee't the appropriate sub-paragraphs (a-f)
Cr *' M c" M N O cl of section III.G-2 of Appendix R.
skaddoam Diagram 2A Diagram 28 Diagram 2C 9
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The following guidelines are for protecting the shutdown capability from fire-induced failures of circuits (cables) in the fire ar.ea. The guidance provided below for interrupting ' devices applies only to new devices installed to provide electrical isolation of associated circuits of concern, or as part of the alternative or dedicated shutdown system. The shutdown capability may be protected from the adverse effect of damage to associated circuits of concern by the following methods:
i 1.
Provide protection between the associated circuits of concern.and the shutdown circuits as per Section III.G.2 of Appendix R, or For a common power source case of associated circuit:
2.
a.
Provide load fuse / breaker (interrupting devices) to feeder fuse / breaker coordination to prevent loss of the redundan' or t
alternative shutdown power source. To ensure that the following coordination criteria are met the 'foT1owing should apply:
(1) The associated circuit of< concern interrupting devices '
(breakers or fuses) time-overcurrent trip characteristic for all circuits faults should cause the interrupting device to interrupt the fault current prior.to initiation l
of a trip of any upstream interrupting device which will cause a loss of the commo~n power source, s'
,(2) The power source shall supply t'he necessary fault current for sufficient time to ensure the proper coordination without loss of function of the shutdown loads.
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c The acceptability of a particular interrupting device is considered demonstrated if the following criteria are met:-
(1) The interrupting device design shall be factory tested to verify overcurrent protection as designed in accordance with the applicable UL, ANSI, or NEMA standards.
(ii)
For low and medium voltage switchgear (480 V and above) circuit breaker / protective relay periodic testing shall demonstrate that the overall coordination scheme' remains within the limits specified in the design criteria. Tfils ~
testing may be performed as a series of overlapping tests.
(iii) Molded case circuit breakers shall peridically be manually exercised and inspected to insure ease of operation., On a rotating r,efueling outage basis a sample of these breakers shall be tested to deterinine that breaker drift is within that allowed by the design criteria.
Breakersshould be tested in accordance with an accepted QC testing methodology such as MIL STD 10 5 D.
(iv)
Fuses when used as interrupting devices do not require periodic testing, due to their stability, lack of drift, and high reliabili.ty. Administrative controls must insure s
that replacement fuses with ratings other than those selected for proper coordinating are not accidentally used.
b.
For circuits of equipment and/or components whose spurious operation would affect the capability to safely shutdown:
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i (1) provide a means to isolate the equipment and/or components from the fire area prior to the fire (i.e., remove power cables, open circuit breakers); or
(?)
provide electrical isolation that prevents spurious operation.
Potential isolation devices include breakers, fuses, ampli-fiers, control switches, current XFRS, fiber optic couplers, relays and transducers; or (3) provide a means to detect spurious operations and then proce-dures to defeat the maloperation of equipment (i.e., c1'osure
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of the block valve i,f PORV spuriously operates, opening of the breakers to remove spurious operation of safety injection);
For comon enclosure cases of associated circuits:
c.
(1) provide appropriate measures to prevent propagation of the fire; and (2) provide electrical protection (i.e., breakers, fuses or similardevices)
C.
We recognize that there are different approaches which may be used to reach the same objective of determining the interaction of associated circuits with shutdown. systems'. One approach is to start with the fire s
ares, identify what is in the fire area, and' determine the interaction between what is in the fire area and'the shutdown systems which are outside the fire area. We have entitled this approach "The Fire Area Approach." A second approach which we have named "Th.e Systems Approach" would be to define t.he shutdown systems around a fire area and then determine
those circuits that are located in the fire area that are associated with the shutdown system. We have prepared two sets-of requests for information, one for each approach. The licensee may choose to respond to cither set of requests depending on the approach selected by the licensee.
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FIRE AREA APPROACH 1.
For each fire area where an alternative or d'edicated shutdown method,
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in accordance with Section III.G.3 of Appendix R is provided, the following information is required to demonstrate that associated circuits will not prevent operation or cause maloperation of the
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alternative or dedicated shutdown method:
a.
Provide a table that lists all the power cables in the fire area
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that connect to the same power supply of the. alternative or
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dedicated shutdown method and the function of each power cable listed (i.e., powe'r for RHR pump).
b.
Provide a table that lists all the cables in the fire area that were considered for possible spurious operation which would adversely
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affect shutdown and the function of each cable listed.
c.
Provide a table that lists all the cables in the fire area that share a common enclosure with circuits of the alternative or dedicated shutdown systems and the function of each cable listed.
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Show that fire-induced failur,es (hot shorts, open circuits or shorts to ground) of each of the cables listed in a; b, and c will not prevent operation or cause maloperation of the alternative or dedicated shutdown method.
e.
For each cable listed in a, b and c where new electrical isolation has been provided or modification to existing electrical isolation has been made, provide detailed electrical schematic drawings that show how each cable is isolated from the fire area.
SYSTEMS APPROACH 1.
For each area where an alternative or dedicated. shutdown method, in accordants with Section. III.G.3 of Appendix R is provided, the following information is required to demonstrate that associated circuits will not prevent operation or cause maloperation of the alternative or dedicated shutdown method:
Describe the methodology used to assess the potential of associated a.
circuit adversly affecting the alternative or dedicated shutdown, The description o,f the methodology should include the methods used to identify the circuits'which share a connon power supply or a connon enclosure wit,h the alternative or dedicated shutdown
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system and the circuits whose spurious operation would affect shutdown. Additionally, the description should include the methods used to identify if these circuits are associated circuits i
of concern due to their location in the fire area.
b.
Provide a table that lists all associated circuits of concern P
located in the fire area.
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Show that fire-induced failures'(hot shorts, open circuits or c.
shorts to ground) of each of the cables listed in b will not prevent operation or cause maloperation of the alternatife or dedicated shutdown method.
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For each cable listed in b where new electrical isolation has been d.
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provided, provide detailed electrical schematic drawings that show how each cable is isolated from the fire area.
Provide a location at the site or other offic'es wherp all the e.
tables and drawings generated by this metho'dology approac_h for the associated circuits review may be audited to verify,the information proviifed above.
HIGH-l.0W PRESSURE INTERFACE
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For either approach chosen the following concerp dealing with high-10w.
prc;;ure interface should b'e addressed.
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2.
The residual heat removal system is generally a low pressure system that interfaces with the high pressure primary coolant system. To preclude a LOCA through this interface, we requie compliance with the recommendations of Branch Technical Position RSB 5-1.
Thus,.the interface most likely consists of. two redundant and independent motor operated valves. These two motor operated yalves and theig associd}ed 1
cables may be subject to a single f. ire hazard.
It is our concern that.
l thi.s single fire could cause the two va]ves to opgn resulting in l
a fire initiated LOCA through the high-low pressure system interface. To assure that this interface and other high-low p
pressure interfaces are adequately protected from the effects of a single fire, we require the following information:
a.
Identify each high-low pressure interface that uses redundant electrically controlled dev' ice (('such as two series motor operated valves) to isolate or preclude rupture of any primary coolant boundary.
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b.
For each set of redundant valves fdentified in a., verify the redundant cabling (power and control) have adequate physical separation as required by Section III.G.2 of Appendix R.
c.
For each case where adequate sep: ration is r.ct previded, shm: tSct fire induced failures (hot short, open circuits or short to ground) of the cables will not cause maloperation and result in a LOCA.
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CRIT'ERIAFOREVAEUATING EXEMPTIONS TO SECTION III G 0F APPENDIX R i
OF 10 CFR PART 50 Paragraph 50.48 Fire Protection of 10 CFR Part 50 requires that all nuclear power plants licensed prior to January 1,1979 satisfy the requirements of Section III.G of Appendix R to 10 CFR Part.50.
It also requires that alternative fire protec ion configurations, previously appioved by an SER be reexamined fo}r compliance with the requirements of Section III.G.
Section III.G is related to fire i
protection features for ensuring that systems and associated circuits i-used to achieve and maintain safe shutdown -are free of fire damage.
Fire protection configurations' must either meet the specific require-ments of Section III.G or an alternative fire protection configuration' must be justified by a fire hazard analysis.
The general criteria for accepting an alternative fire protection configur-ations are the following:,
The alternative assures that one train of equipment necessary to achieve hot shutdown from either the control room or emergency control stations is free of fire damage.
The alternative assures that fire damage to at least one train of equipment necessary to achieve cold shutdown (minor repairs with is limited such that it can be repaired within a reasonable time components stored on-site).
Fire retardant coatings a.re not used as fire barriers.
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MQdificatil5ns reqqired to meet Section III.G would.not enhance fire protection' safety above ~that pro,vided by either existing or proposed alternatives.
Mpdifications required to meet Segtion Ill.G would be detrimental to overall facility safety.
Becai e of the broad spectrum of potential configurations for which exempeions may be, requested, specific criteria that account for all of
' the parameters that are important to fire protection and consistent with safety requirements of all plant-unique configurations have not been developed.
However, our evaluatio6s of deviations from these require-ments in our grevious reviews and in the request's for III.G exemptions received to date have identified some recurring configurations for which specific criteria have been developed.
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Section III.G.2 accepts three methods of fire protection.
A passive 3-hour fire barrier should be used where possible. Where a fixed barrier cannot be installed, an automatic suppression system in combination with
. a fire barrier or a separation distance free of combustibles is used if the configurations of systems to be protected and in-situ combustibles are such that there is reasonable assurance that the protected systems will survive.
If this latter condition is not met, alternative shutdown capa-bility is required and a fixed suppression system installed in the fire area of concern, if it contains a large concentration of cables.
It is essential to remember that these alternative requirements are not deemed to be equivalent.
However, they previde adequate protection for those configurations in which they are ac epted.
Wheri the fire protection f.eatures of each fire area are evaluated, the whole system of such features must be kept in perspective. The defense-in-depth principle of fire protection programs is aimed at achieving an.
adequate balance between the different features. Strengthening any one -
can compensate in some measure for weaknesses, known or unknown in others.
The adequacy of fire protection for any particular plaat safety system or area is deterTnined by antlysis of the effects of postulated fire relative to maintaining the ability to safely shutdown the plant and minimize radio-active releases to the environment in the event of a fire. During thes,e evaluations it is necessary to consider the two-edged nature of fire protection features recognized in General Design Criterion 3 nanely, fire protection should be provided consistent with other safety considerations.
An evaluation must be made for each fire area for which an exe. option is requested.
During these evaluations, the staff considers the f6110 wing parameters:
'A.
Area Description walls, floor, and ceiling construction ceiling height room volume ventilation congestion B.
Safe Shutdown Capability l
number of redundant systems in area 3
whether or not system or equiment is rcquired for hot shutdown type of equipment / cables involved repair time for cold shutdown equipmnt within this area separation between redundant co:$ponents and in-situ concentration of combustibles alternative shutdown capability 5
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Fire Hazard Analysis type and configuration of combustibles in area quantity of combustibles ease of ignition and propagation heat release rate potential transient and installed combustibles suppression damage to equipment whether the area is continuously manned traffic through the area accessibility of the area D.
Fire Protection Existing or Committed fire detection systems fire extinguishing systems ho.se station / extinguisher radiant heat shields-A specific description of the fire protection features of the configuration is required to justify the compensating features of the alternative. Low fire loading is not a sufficient basis for granting an exemption in areas
'where there are cables.
I If necessary, a team of. experts, including a fire protection engineer, will' visit the site to determine the existing circumstances. This visual inspection is also considered in the review process.
I The majority of the III.G exemption requests received to date are being denied'because they lack specificity. Licensees have not identified the extent of the exemption requested, nave not provided a technical basis For the request and/or have not provided a specific description of the alternative. We expect to receive requests for exemption of the following nature:
1 1.
Fix'ed fire barriers less than 3-hour rating.
2.
Fire barrier without an automatic. fire suppression system.
3.
Less than 20 feet separation of cables with fire propagation retardants (e.g., coatings, blankets, covered trays) and an 3
automatic suppression system.
For large open areas with few comp"on'ents to be protected and few in-situ 4.
combustibles, no automatic suppression systgm with separation as in Item 3 above.
5.
No fixed suppression in the contr'ol room.
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No fixed suppression in areas without a large concentration of cables for which alternative shutdown capability has been provided.
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Our fire research test program is conducting tests to provide information that will be useful to determine the boundary of acceptable conditions for fire protection configurations which do not include a fire rated barrier.
Based on deviations recently approved, specific criteria for certain recurring configuratians are as follows:
Fire Barrier t.ess thin Three Hours This barrier is a wall, floor, ceiling or an enclosure which separates one fire area from another.
Exemptions may be granted for a lower rating (e.g., one hour cr two hou's) r where the fire loading is no more than 1/2 of the barrier rating. The fire rating of the barrier shall'be no less than one hour.
Exemptions may be granted for a fixed barrier with a lower fix rating supplemented by a water curtain.
An Automatic Suppression System With Either One Hour Fire Barrier or 20-Foot Separation This barrier is an enclosure which separates those portions of on,e division
'which are within 20 feet of the redundant division.
The suppressant may be water or gas.
Exemptions may be granted for ~ configurations of redund3nt systems which l
'hav'e compensating features.
For example:
A.
Separation distances less than 20 feet may be deemed acceptable where:
1.
Fire propagation retardants (i.e., cable coatings, covered trays, conduits, or mineral wool blankets) assure that fire propagation through in-situ combustibles will not occur or will be delayed l
sufficiently to ensure adequa.te time for detection and ~ suppression.
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2.
Distance abve a floor level exposure fire and below ceiling assures that redundant systems will not be simultaneously subject to an l
unaf;ceptable temperature or heat flux.
l B.
The ommission of an automatic sup"pr'ession system may be deemed acceptable where:
1.
Distance above a floor level exposure fire and below ceiling assures j
that redundant systems will not be simultaneously subject to an unacceptable temperature or heat flux.
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o 5-The fire area ks required to be manned continuously by the provisions 2.
in the Technical Specifications.
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