ML20053B105
| ML20053B105 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 05/04/1982 |
| From: | Harold Denton Office of Nuclear Reactor Regulation |
| To: | NORTHERN STATES POWER CO. |
| Shared Package | |
| ML20053B106 | List: |
| References | |
| TAC-11094, TAC-11095, NUDOCS 8205280050 | |
| Download: ML20053B105 (30) | |
Text
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ENCLO3UEE '
NUCLEAR REGULATORY COMMISSION In the Matter of
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NORTHERN STATES POWER
) Docket Nos. 50-282 and 50-306 COMPANY
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(Prairie Island Nuclear Generating
)
Plant Unit Nos.1 and 2)
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EXEMPTION I.
The Northern States Power Company (the licensee) is the holder of Facility Operating License Nos. DPR-42 and DPR-60 which authorize operation of the Prairie Island Nuclear Generating Plant, Unit Nos.1 and 2.
These licenses provide, among other things, that they are subject to all rules, regulations and Orders of the Commission now or hereafter in effect.
The facil.ity comprises two pressurized water reactors at the licer.see's site located in Goodhue, Minnesota.
II.
On November 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 F.R. 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 fifteen subsections, lettered A through 0, each of which specifies requirements for a particular aspect of the fire protection features at a nuclear power plant. Two of these fifteen subsections, III.G. and III.J, are the subject of this exemption request. 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 separa-tion and barriers could not be met in an area, alternative safe shutdown capability, independent of that area and equipment in that area, is required l
(III.G.3.).
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- Subsection III.J specifies detailed requirements for providing erer-gency lighting in all areas needed for operation of safe shutdown equipment.
Section 50.48(c) requires completion of all modifications to meet the provisions of Appendix R within a specified time from the effective date of this fire protection rule, February 17, 1981, except for modifications to provide.
alternative safe shutdown capability. These latter modifications (III.G.3.)
require NRC review and approval. Hence, Section 50.48(c) requires their corpletion within a certain time after NRC approval.
The date for submittal of. design descriptions of any modifications to provide alternative safe shutdown capability was specified as March 19, 1981.
Section 50.48(c)(3) specifies the installation schedule of those fire protection features such as emergency lighting (III.J) that require a plant shutdown to complete the installation.
The installation schedule in Section 51.48(c)(3) requires the completion of the installation of such fire protection features during the first refueling outage commencing after 180 days from the effective date of Appendix R (February 17,1981). Hence, Section 50.48(c)(3) requires the licensee to complete the installation of the emergency lighting (III.J) during the first refueling outage commencing after August 17, 1981 for each unit.
By letters dated March 13, March 19, November 16, and December 1,1981, and February 5,1982, Northern States Power Company requested exemptions from 10 CFR 50.48(c) 'with respect to the requirements of Sections III. G and III.J of Appendix R as follows:
(1) Extend the date in paragraph (c)(5) for submitting plans and schedules l
-for meeting the provisions of paragraphs (c)(2), (c)(3), and (c)(47 l
with respect to the requirements of Section III.G of Appendix R, and i
for submitting design descriptions of modifications needed to satisfy Section III.G.3 of Appendix R, from March 19, 1981 to July 1,1982.
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. (2) Extend the implementation date in paragraph (c)(2) fcr 4stallation of modifications required by Appendix R,Section III.G.2, that do not require prior NRC approval or plant shutdown, from nine months af ter February 17, 1981 to nine months after June 1,1982.
(3) Extend the implementation date in paragraph (c)(3) for. installation of modifications required by Appendix R,Section III.G.2, that do not require prior NRC approval, but require plant shutdown, from before startup af ter the first refueling or extended outage commencing 180 days or more after February 17, 1981, to before startup after the first refueling or extended outage commencing 180 days or more af ter June 1,1982.
(4) Extend the implementation date in paragraph (c)(3) for modifications required by Appendix R Subsection III.J that do not require prior NRC approval but require a plant shutdown, from the first refueling shutdown or extended outage commencing after 180 days from the effective date of Appendix R for each unit to the refueling outage scheduled for autumn of 1982 for Unit 1 and scheduled for spring of 1982 for Unit 2.
When this Fire Protection Rule was approved by the Commission,. it was understood that the time required for each licensee to re-examine those previously-approved configurations at its plant to detemine 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 conformance. For each item of non-conformance that was found, a fire hazards analysis had to be performed to determine whether the existing configuration provided sufficient fire protection.
If it d.id, 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 fire protection features alone could not ensure pro-tection 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 areat involved, the time required for this re-examination, reanalysis and redesign could vary from a few months to a year or more. The Commission decided, however, to require one, short-tenn date for al-1 licens%: in the interest of ensuring a best-effort, expedited. completion i
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. of compliance with the Fire Protection Rule, recognizing that there would be a number of licensees who could not meet these time restraints but who could then request appropriate relief through the exemption process. Licensees for 44 of the 72 plants to which Appendit R applies (plants with an operating license issued prior to January 1,1979) have requested such schedular relief.
The licensees for the remaining 28 piants made submittals to meet the schedular. requirements of 50.48(c). All of thes.e submittals, however, were deficient in some respects.
In general, much of the information requested in h generic letter (81-12) dated February 20, 1981, to the licensees of all 72 plants, was not provided. Therefore, additional time is being use'd to complete those submittals also.
III.
Prior to the issuance of Appendix R, the Prairie Island Units had been reviewed against' the criteria of Appendix A to the Branch Tech'nical Position 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 Plant.
It is broader in scope than Appendix R, and formed the nucleus of the criteria developed further in Appendix R.
In its present revised form the BTP 9.5-1 constitutes the section of 'the Standard Review Plan used for the review of applications fof' construction
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permits and operating licenses of new plants. The review was comple'ted by the NRC staff and its fire protection consultants and a Fire Protection Safety Evaluation (FPSER) was issued. A few items remained unresolved. Further
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discourse between the licen'see'and the NRC staff resulted in resolution of all ofthe'se items as documented in two supplementsl to the FPSER except
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SER Supplements issued by letters dated April 21, and December 29, 1980 I
of compliance with the Fire Protection Rule, recognizing that there would be a number of licensees who could not meet these time restraints but who could then request appropriate relief through the exenotion 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 information 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 cocplete those submittals also.
III.
Prior to the issuance of Appendix R, the Prairie Island Units had been reviewed against the criteria of Appendix A to the Branch Technical Fosition 9.5-1 (BTP 9.5-1).
The BTP 9.5-1 was developed to resolve the lessons learned f rom the fire at Browns Ferry Nuclear Plant.
It is broader in scope than Appendix R, and formed the nucleus of the criteria developed further in Appendix R.
In its present revised form the BTP 9.5-1 constitutes the section of the Standard Review Plan used for the review' of applications far construction permits and operating licenses of new plants.
The review was completed by
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the NRC staff and its fire protection consultants abd a Fire Protection Safety Evaluation (FPSER) was issued. A few itens remained unresolved. Further discourse between the licensee and the NRC staff resulted in resolution of 1
all of these items as ' documented in two supplements to the FPSER except 1/
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29, 1980 SER Supplements issued by letters dated April 21, and December
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. for the alternate shutdown capabilities which is the subject of this exemption.
The FPSER supported the issuance of amendments to the operating licenses ~
of the Prairie Island UnitsN which required modifications to be made to plant physical features, systems, and administrative controls to meet the criteria of Appendix A to BTP 9.5-1.
All of these modifications have been corpleted. Therefore, the Prairie Island Units have been upgraded to a high degree o'f fire protection already and the extensive reassessment involved in this request 'or additional time is to quantify, in detail, the differences between what was recently approved and the specific requirements of Section III.G to Appendix R of 10 CFR 50.
J By letter dated December 18, 1981, Northern States Power Company did submit for our review a Fire Protection Safe Shutdown Analysis giving plans and schedules for achieving compliance with Appendix R Section III.G. However, after noting several information deficencies in its submittal, the licensee requested an exemption frcm Sectior 50.48(c) to conduct a second level review of their analysis and prepare a supplement to the original submittal. The licensee also stated in the request for exemption that the additional time is needed to present a thorough and auditable process by which conformance I
with Section III.G of Appendix R is accomplished.
By letters dated November 16 and December 1,1981, the licensee requested additional time for completing modifications to meet requirements of subsection III.J, emergency lighting.
Subsection 50.48(c)(3) requires that these modifi-cations be completed during the first refueling outage after August 17, 1981.
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MPrairie Island Unit 1 - Operating License DPR-42 Amendment 39 supported by FPSER issued September 6,1979 Prairie Island Unit 2 - Operating License DPR-60 l
Amendment 33 supported by FPSER issued September 6,1979 1
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. The first refueling outage for Unit 1 occurred in September 1981 and for Unit 2 the.first refueling outage is planned for the spring of 1982. Therefore the exemption is requested for Unit 1 for the completion date of the emergency lighting to be during the second refueling outage af ter August 17, 1981.
The licensee has committed to complete the modifications during the spring -
refueling outage for Unit 2 which is the first outage after August 17, 1981, and therefore an exemption from Subsection 50.48(c)(3) is not necessary for Unit 2.
For Unit 1 a time restraint was created since the licensee is required by Subsection 50.48(c)(3) to perform the necessary engineering analysis, design, purchase and installation of necessary equipment within a period of seven months.
We agree that the licensee in this instance applied a best effort and the time allowed turned out to be insufficient.
In addition, portable lighting units are available for use by operators and the fire brigade members as an interim measure until completion. On this basis the staff has judg'ed that the request for exemption for Unit 1 to allow additional time to complete the installation of emergency lighting at the refueling outage scheduled for autumn of 1982 should be granted.
Based on the above considerations, we find that the licensee has completed a substantial part of the fire protection features at Prairie Island Units 1 and l
in conformance with the requirements 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 Sections III.G and III.J.
We find that because of the already-completed upgrading of t' ese facilities, h
there is no undue risk to the health and safety of the public involved with l
continued operation until the completion of this reassessment on July 1,1982.
i Therefore, an exemption should be granted to allow such time for completion.
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< However, because 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 Exemption that requires all such information to be submitted by the date granted.
IV.
Accordingly, the Commission has determined that, pursuant to 10 CFR 50.12, an exemption is authorized by law and will not endanger life or property or the common defense and security and is otherwise in the public interest and hereby grants the following exemptions with respect to the requirements of Section III.G amd III.J of Appendix R to 10 CFR 50:
(1) Extend the date in paragraph (c)(5) for submitting plans and schedules for meeting the provisions of paragraphs (c)(2), (c)(3), and (c)(4) with respect to the requirements of Section III.G of Appendix R, and for submitting design descriptions of modifications needed to satisfy Section III.G.3 of Appendix R, from March 19, 1981 to July 1,1982.
(2) Extend the implementation date in paragraph (c)(2) for installation of modifications required by Appendix R,Section III.G.2, that do not require prior NRC approval or plant shutdown, from nine months after February 17, 1981 to nine months af ter June 1,1982.
(3) Extend the implementation date in paragraph (c)(3) for installation of modifications required by Appendix R,Section III.G.2, that do not require prior NRC approval, but require plant shutdow, from
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before startup after the first refueling or ext (nded outage, commencing 180 days or more after February 17, 1981, to before startup af ter.
the first refueling or extended outage commencing 180 days or more af ter June 1,1982.
(4) The implementation date in paragraph (c)(3) for modifications required
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by Appendix R Subsection III.J is extended for Unit 1 from the first refueling outage aft 6r August 17, 1981 to the second refueling outage
,after August 1,7, 1981 or an extended outage as defined in 10 CFR 50.48(c)(3) ~com'mencing more than 180 days after the date of this exemption.
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. Provided the following condition is met:
The design descriptions of alternative or dedicated shutdown systems to comply with Section III.G.3., as required by 50.48(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.
If the licensee does not 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 beginning with the date set in the exemption for submittal and terminating when all inadequacies are corrected.
A delay in the determination of inadequacy by the staff, caused by the work-load 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 submit-
- al, nor will such delay cause any penalty that may be imposed to be mitigated.
The NRC staff has determiced 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 environ -
mental impact appraisal need not be prepared in connecti6n wit'h is action.
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th FOR THE NUCLEAR REGULATORY COMMISSION Y
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n Harold R. Denton, Director Office of Nuclear Reactor Regulation Dated at, Bethesda, Maryland, this 4th day of May, 1982 l
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CLARIFICATION OF GEtlERIC LETTER On February 20, 1981, generic letter 81-12 was forwarded to all reactor licensees with p.lants 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-ments of Section III.G.2 of Appendix R to 10 CFR 50 were satis'fied. Additionally, and Enclosure 2 of the generic letter requested additional
.infomation concerning those areas of the plant requiring alternative shutdown
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capabili ty. Section 8 of Enclosure 1 requested information for the systems, equipment and procedures of alternative shutdown capability and Enclosure 2
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defined associated circuits and requested information concerning associated circuits for those areas requiring alternative shutdown.
In our review of licensee submittals and meetings 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 information. Thus, the staff has rewritten Section 8 of Enclosure 1 and
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--. Enclosure 2 of the February 20, 1981 generic letter. Additiginally, further clarification of the definition of associated circuits has been provided to aid in the reassessments to determine compliance with the requirements of Sections III.G.2 and III.G.3 of Appendix R.
In developing this* rewrite we have The enclosed considered the comment of the t uclear Utility Fire Protection Group.
rewrite of the Enclosures contains no new requirements but merely attempts to clarify the request for additional information.
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2-Licen'ees who have not responded to the February 20, 1981 generic letter, s
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 identifications of a major unresolved item (iie., associated circuits),
may choose to respond to pertinent sections of the enclosed request for infor-
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mation in order to close open items (i.e., open item for. associated circuits, use rewrite of Enclosure 2).
If additional clarification is needed, please contact the staff Project llanager for your plant.
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REWRITE OF SECTION 8 REQUEST FOR ADDITIONAL INFORMATION The following is a rewrite of the staff's request for additional information concerning design modification to meet the requirenents of Section III'.G.3 of Appendix P..
The following contains no new requests but is merely a rewording of Section 8 of Erclosure 1 of the February 20,'1931 generic letter.
1.
Ide'ntify those areas of the plant that will not meet the requirements of Section III.G.2 of Appendix R and, thus alternat1ve shutdown will be providels,
, or an exemption from the requirements of Section III.G.2 of Appendix R will be orovided. Additiona:1y provide a statement that all other areas of the plant are or will be in compliance with Sec. tion III.G.2 of Appendix R.,
For each of those fire areas of the plant requiring an alternative shutdown system (s) provide a complete set of responses to the following requests for each fire area:
List the system (s) or portions thereof used to provide the shutdown a.
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 equipment and ccmponents of the normal ' shutdown system'in the fire area and identify 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 capability for the. fire a.rea and provide a table that lists the equipment.
and components of the alternative shutdown 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 rea in accordance with Section III.G.2.
c.
Provide drawings of the alternative shutdown system (s) which highlight any conne_ctions to the normal sh'utdown systems (P& ids for piping ano components, elementary wiring diagrams of electrical cabling).. Showthe 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 safety systemst (e.g., new isolation switches and control switches should meet design criteria and standards in the FSAR 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 switc'h is in the proper position fe -
nor:aa'l operation; and a single transfer switch oh other new' device should not be a source of a failure which causes loss of reounaans safety -
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el Verify that licensee procedures have been or will, be develo' ped which descril
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l tasks to be perfomed to effect the shutdown. method.
Provide a summary
.of these procedures outlining operator actions.
3-f..
Verify that the manpower required to perform the shutdown funct' ions using the procedures of e:. as well as to provide fire brigade members to fight the fire is available as required by the fire brigade technical speci-fications.
g.
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 c'ontrol room; and that equipment operates from'the control room but cannot be operated at the local control station when the transfer isolation switch is in the " remote" position.
h.
Provide Technical Specifications of the surveillance requirements and limiting conditions for operation for that equipment not already '
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covered by existing Technical Speci fications.
For. example, if new isolatio.n and control switches are added to a shutdown system, the existing Technical Specification surveillance requirements should
.be supplemented to verify system / equipment functions from the alternate shutdown station at testing intervals consistent with,the guide 5ir.es 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 the necessary shut-down function. The functions required should be based or previous analyses, if possible (e.g., in the FSAR), such as a loss of nomal ac
' power or shutdown on Group 1 isolation (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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ANCLOSURE 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 followl,ng_tequirements also apply to cold s,hutdown equipment if tha licensee elects to'deEonstrAte that the.equipaent.is to be free of. fir,e. damage. AppendE R does allow.re'pairable damage to cold shutdown ecuipment.
Using th,e requirements of Sections III.G and III.L of Appendix R, the ca'pa-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 th'e 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 eqtripment needed for hot shutdown:
1.
Redundant systems including cables, equipment, and associated circuits may be separated by a three-hour fire rated barrier; or, 2.
Redundant systems including cables, equipment and associated ci.rquits may be separated by a horizontal distance of more than 20 f' et with no inter-e i
i 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 barrier.
In addition, fire detectors l
and an iutomatic fire suppression system are required.
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The last option as defined b,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 cabl'es, 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 consideration, B) the guidelines for protecting the safe shutdown capability from the fire-induced failures of associated circuits and C) the in-formation required by the staff to review associated circuits. The definition 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 reouirements. These guidelines should be used only as guidancs 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 failures will be evaluated by the staff for acceptability..
Our concern is that circuits sithin the fire area,will, receive fir.e damage A.
which can affect shutdown capability and thereby prevent post-fire safe Associated Circuits
- of Concern are defined as those cables
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shutdown.
(safety related, non-s'afety related, Class lE, and non-Class ~1E) that:
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- The definition for associated circuits is not exactly the same s
as the definition presented in IEE.E-384-1977.
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1.
Have'a physical separation less than that required by Section III.G;2 of Appendix R,.and; 2.
Have one.of the following:
a common power source with the shutdown' equipment (redundant or a.
alternative) and the power source is not electrically protected from the circuit of concerp by coordinated breakers, fuses, o~r similar devices (see diagram 2a), or b.
a connection to circuits of equipment whose spurious operation would a'dversely affect the shutdown capability (e.g., RHR/RCS isolation valves, ADS valves, PORVs, steam gen'erator atmospheric dump valves, instrumentation, steam bypass, etc.) (see diagram 2b), 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 C0flCERN_
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FIRE. AREA
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l "The area barriers shown above meet
.E p p ed. a.,e sfau'. ens the appropriate sub-paragraphs (a-f) n - huS i
ft' A co a a7 fe d of section III.G-2 of Appendix R.
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i SAuldoam ik Diagram 2A Diagram 28 Diagram 2C s
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The following guidelines are for protecting the shutdown capability from fire-induced failures of circuits (cables) in the fire area. The guidance provided below for interrupting devices applies only to new devices in' stalled 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:
1.
Provide protectio'n,between the associated circuits of concern and the shutdown circuits as per Section III.G.2 of Appendix R, or 2.
a.
For a comon power source case of associated circuit:
provide load fuse / breaker (interrupting devices) to' feeder fuse / breaker coordination to prevent loss of the redundant or alternative shutdown power source. To ensure that the following coordination criteria are met the 'fol;1owing should apply:
(1) The associated circuit of concern interrupting devices '
(breakers or. fuses) time-overcurrent trip characteristic for all circuits faults should cause the interruptin.g device to interrupt the fault current prioi to initiation
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of a trip of any upstream interrupting device which will.
cause a loss of the comon power source.
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,(_2) The power sourc shall supply t'he necessary fault current for sufficient time to ensure the proper coordination i
without loss of function of the shutdown loads.
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The acceptability of a particular interrupting device is considered demonstrated if the following criteria are met:
(i)
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. This testing may be performed as a series of overlapping tests.
(jii) Molded case circuit breakers shall peridically be manually exercised and inspected to insure ease of operation. On a rotating refueling outage basis a' sample of these breakers
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shall be tested to determine that breaker drift is within
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that al'1 owed by the design criteria.
Breakersshould be tested in accordance with an accepted QC testing methodology s0ch 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 reliability. Administrative controls must insure 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 s'afely shutdown:
s (1) provide a meant to isolate the equipment and/or components from the fire area prior to the fire (i.e., remove power cables, open
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circuitbreakers);or (2) provide electrical isolation that prevents spurious operation.
Potential isolation devices include. breakers, fuses, ampli-fiers, control switches, current IFRS, 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.d., closure of the block valve if PORY spuriously operates, opening of the breakers to remove spurious operation of safety injection);
For common enclosure cases of associated circuits:
c.
(1) provide appropriate measures to prevent ' ropagation of the p
fire; and (2) provide electrical protection (i.e., breakers, fuses or similardevices)
We recognize that there are different approaches which may be used to C.
reach the same objective of determining the interaction of associated circuits with shutdown systems. One approach is to start with the fire area, identify what is,in the fire area, and' determine the interaction between what is in the fire area and the shutdown systems which are outs de the fire area. We have entitled this approach "The Fire. Area Approach." A second approach which we'h' ave named "The Systems Approach" would be to define the shutdown systems around a fire area and then determire 1,
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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 either set of requests depending on the approach selected by the licensee.
FIRE AREA APPROACH 1.
For eac'h fire area where an alternative or dedicated shutdown method, in accordance with Section III.G.3 of Appendix R is provided, the following infomation is required to demonstrate that associated circuits will not prevent operation or cause maloperation of the alternative or dedicated sliutdown 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 dedicated shutdown method and the function of each power cable listed (i.e., power 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 affect' shutdown and the function of each ' cable. listed. --
c.
Povide a table that lists all the cables.in the fire area that
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. share a common enclosure with circuits of the alternative or dedicated shutdown systems and the function of each cable listed.
d.
'Show that fire-induced failures (hot shorts, open circuits or
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shorts to ground) of each of the cables listed in a; b, and c,will l
not prevent operation or cau,se malor ration of the alternative or dedicated shutdown method.
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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.
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SYSTEMS APPROACH
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1.
For each area where an alternative or dedicated shutdown method, 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 alternative or dedicated shutdown method:
a.
Describe the methodology used to assess the potential of associated circuit adversly affecting the alternative or dedicated shutdown.
The description of the methodology should include the methods used to identify the circuits which share a comon power supply or a comon enclosure with the alternative or dedicated shutdown system and the circuits whose spurious operation would affect i
shutdown. Additionally, the description should include the methods used to identify if these circuits are associated circuits of concern due to their location in the fire area.
b.
Provide a table that lists all associated circuits of concern located in the fi're irea.
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Show that fire-induced failures (hot shorts, open circuits or c.
I 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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-9 d.
For each cable listed in b where new electrical isolation has been 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'e,s where gli the e.
tables and drawings generated by this metho'd51o'gy approac_h for the associated circuiti; review may be pudited to verify,the information provided above.
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HIGH-LOW PRESSURE INTERFACE For either approach chosen the following concern dealing with high-low.
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pressure interface should M addressed.
2.
The res.idual heat removal system is generally a low p,res,sure system that interfaces with the high pressure primary coolant system. To preclude a LOCA through this interface, we require co,mpliance with the recommendations of Branch ' Technical Position RSB 5,1.
Thus, the interface most likely consists of'two redundant and independent motor orerated valves. These two motor operated valves and their associdted
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cables may be subject to a single f. ire hazard. It is'ou~r c~6ncern that
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this single fire could cause the two valves'to open resulting'in 5
a fire initiated LOCA through. the high-low pressure system interface. To assure that this interface and other high-low pressure interfaces are adequately, protected from the effects of a single fire, we require the following information:
1 l
a.
Identify each high-low pressure interface that uses redundant I
electrically controlled dev' ices. (such.as two series motor operated f
valves) to isolate or preclude' rupture of any primary coolant boun' a ry.
d
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For each set of redundant valves fdentified in a., verify the b.
redundart cabling (power and control) have adequate physical separation as required by Section III.G.2 of Appendix R.
th.ct For each case where adequate sep ration is r.ct provided, shot:
c.
fire induced failures (hot short, open circuits or short to sc
- of the cables will not cause maloperation and result in a 1.0CA e
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3.
CRITERIA F0P EVALUATING _
EXEMPTIONS TO SECTION III G OF APPENDIX R 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 protection configurations, previously approved by an SER be reexamined for compliance withSection II
-he requirements of Section III.G.
protection features for ensurin; thtt systems and associated circuits usied to achieve and maintain safe shutdown.are free of fire damage.
Fire protection configurations must either meet the specifi
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must be,jdstified by a fire hazard ana}ysis.
The general criteria for accepting an alternative fire orotection configur-ations are the following:.
The alternative assures that one train of equipment nece stations is free of fire damage.
The alternative assures that fire damage to at least one train of equipment necqssary to achieve cold shutdown is limited such tt)at it can be repaired within a reasonable time (minor repairs with components stored on-site).
Fire retardant coatings are not'used as fire barriers.
Modifications required to meet Section III.G would.not enhance fire protection safety above that providpd by either exipting or proposed alternatives.
Modifications required to' meet Section III.G would be detrimental to overall facility sgfety.
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the broad spectrum of potential configurations for which f
exemptions may be, requested, specific criteria that account for Because o t with the parameters that are important to fire protection and co safety requirements of 4However, our evaluations of deviations from these i
ments in our grevious reviews and in the reques developed.
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I specific criteria have been developed, i
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2-A passive'Section III.G.2 accepts three methods of fire protection.Where a fixed barrier 3-ho'ur fire barrier should be used where possible.
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 If th s latter condition is not met, alternative shutdown capa-bility is required and a fixed suppression system installed in tha fire' survive.
It~is area of concern, if it contains a large concentration of ca However, they provide adequate protection for those to be equivalent.
configurations in which they are accepted.
Wheri the fire protection fe'atures of each fire. area are evaluated, the The defense-whole system of such features must be kept in perspective.
in-depth principle of fire protection programs is aimed at achieving an Strengthening, any one adequate balance between the different features.can compen The adequacy of fire protection for any particular pl. ant safety system or area is determined by analysis of the effects of pos 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 Desi An evaluation must be made.for each fire area for which is requested.
parameters:.
'A.
Area Description walls, floor, and ceiling construction
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ceiling height
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room volume ventilation I
congestion Safe Shutdown Capability B.
number of redundant systems in area whether or not s'yst~em or equiment is required for hot shutdown
-type of equipmen'/ cables involved repair time for cold shutdown equipmnt within this area separation between redundant components and in-situ concentration of combustibles I
alternative shutdown capability h
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C.
Fire Hazard Analysis type and configuration of combustibles in area quantity of combustibles ease of ignition and propagation heat release rate potential transien.t and installed combustibles suppression damage tc 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 1
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, This' visual
.will visit the site to determine the existing circumstances.
inspection is also considered in the review process.
The majority of the III.G exemption requests received to date are being Licensees have not identified denied because they lack specificity.
the extent of the exemption requested, have not provided a technical basis For the request and/or have not provided.a specific description of the l
We expect to receive requests for-exemption of the f.ollowing alternative.
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nature:
Fixed fire barriers less than 3-hour rating.'
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1.
l Fire barrier without an automatic fire suppression system.
2.
Less than 20 feet separation of cables with fire propagation 3.
retardants (e.g., coatings, blankets, covered trays) and an automatic suppression system.
k
.For large open areas with few components to be protected and few in-si u t
4.
combustibles, no automatic suporession system with separation as in Item 3 above.
5.
No fixed suppression in the contr'o1 foom.
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No fixed suppression in areas without a large concentration of cables for
-which alternative shutdown capability has been providef.
Our fire research test program is conducting tests to provide information that will be usaful to determine the boundary of acceptable conditions for fire protection configurations which~do not include a fire rated barrier.
Based on dehiations recently approved, specific criteria for certain recurring configurations are as follows:
Fire Barrier Less than 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 or two hou'rs)
The fire where the fire loading is no more than 1/2 of the barrier rating.
rating of the barrier shall'be no less than one hour.
Exemptions may be granted #or 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 one division which are within 20 feet of the redundant division. The suppressant may be water or gas.
Exemptions may be granted for configurations of redundant systems which l
'hav'e compensating features..For examp e:
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 sufficiently to ensure adequate time for detection anOsuppression.
2.
Distance above a. fl.cor level exposure fire and below ceiling assures that redundant systems will not be simultaneously subject to an unaf;ceptable temperature at heat flux.
The ommission of an automatic suppression system may be deemed acceptabi i
B.
f where:
1.
Distance above a floor level exposure fire and below ceiling assurci that redundant systems will not be simultaneously subject to an unacceptable temperature.or heat flux,.
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.2. 'The fire area is required to be manned continuously by the provisions in the Technical Specifications.
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