ML20054F496
| ML20054F496 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 05/19/1982 |
| From: | Harold Denton Office of Nuclear Reactor Regulation |
| To: | Maine Yankee |
| Shared Package | |
| ML20054F495 | List: |
| References | |
| NUDOCS 8206170012 | |
| Download: ML20054F496 (28) | |
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ENCLOSURE 2 NUCLEAR REGULATORY COMMISSION In the Matter of
)
)
MAINE YANKEE ATOMIC POWER
) Docket No. 50-309 COMPANY
)
l (Maine Yankee Atomic Power Plant
)
)
1 EXEMPTION I.
The Maine Yankee Atomic Power Company (the licensee) is the holder of Facility Operating License No. DPR-36 which authorizes operation of the Maine Yankee Atcmic Power Plant. This license provides, among other things, that it is subject to all rules, regulations and Orders of the Commission now or hereafter in effect.
The facility comprises one pressurized water reactor at the licensee's site located in Lincoln County, Maine.
II.
On November 19, 1980, the Commission published a revised Section 10 CFR 50.48 and a new Apper. dix 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 l7,1981. Section 50.48(c) established the sched'ules 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 l
nuclear power plant. One of these fifteen subsections, III.G., is the subject of this exemption request.
III.G. specifies detailed requirements for fire l
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 be met in an area, alternative safe shutdown capability,' independent of that
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area e d equipment in that area, was required (III.G.3.).
8206170012 820519 PDR ADOCK 05000309
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s l Section 50.48(c) required 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 modiffi:ations to provide alternative safe shutdown capability. These latter modifications (III.G.3.)
require NRC review and approval. Hence, Section 50.48(c) reWres 'their completion within a certain time af ter NRC approval. The date for submittal of design descriptions of any modifications to provide alternative safe shutdown capability was specified as March 19, 1981.
By letter dated September 20, 1979, the licensee submitted a description of Maine Yankee's safe shutdown capability. Based on conversation with the NRC staff the licensee understood that its September 20, 1979 description was not entirely acceptable to the staff. Therefore, by letter dated February 9, 1981, the licensee requestad an exemption from 10 CFR 50.48(c) with respect to the requirements of Section III.G of Appendix R as follows:
(1)
Extend from March 19, 1981 to a date six months af ter receipt of NRC staff comments on the licensee',s September 20, 1979 submittal, the submittal schedule for Maine Yankee's alternate shutdown capability resign description.
By letter dated March 6,1981 the licensee supplemented its February 9, 1981 request to include an exemption from certain requirements of Section III.l.
of Appendix R to the extent that section requires the alternate shutdown capa-t bility to accommodate post fire conditions where offsite power is not available.
Futhemore, the licensee's letter of March 12, 1981 states that the development
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of Section III.G infomation must be delayed until the licensee receives a i !
response to both exemption requests.
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Since Section III.L provides the criteria for Alternative Safe Shutdown capability, the resolution of the March 6,1981 exemption request would affect the final reassessment and redesign, if necessary, performed for Section III.G.
Therefore, when we provided, by letter dated April 24, 1981,, our comments on
'l the licensee's September 20, 1979 submittal, we stated that the schedule requirements for the submittal of Section III.G information would be specified J
in conjunction with our response to the March 6,1981 exemption request.
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When this Fire Protection Rule was approved by the Commission, it was j
understood that the time required for each licensee to re-examine those pre-l viously-approved configurations at its plant to determine whether they meet
- j the requirements of Section III.G of Appendix R to 10 CFR 50 was not well known 4
and would vary depending upon the degree of conformance. For each item -of nonconformance that was found, a fire hazards analysis had to be performed to determine whether the existing configuration provided sufficient fire protec-tion.
If it did, a basis had to be formulated for an exemption request.
If
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it did not, modifications to either meet the requirements of Appendix R or f
to provide some other acceptable configuration, that could be justified for an exemption, had to be designed. Where fire protection features alone could 4
not ensure protection of safe shutdown capability, alternative safe shutdown 1
. 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 re-examination, reanalysis and redesign could vary from a few months to a year or more. The Commission decided, fiowever, to require l
one, short-tenn date for all licensees in the interest of ensuring a best-effort, l
expedited completion of compliance with the Fire, Protection Rule, recognizing that there would be a number of licensees who could not meet these time m
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restraints but who could then request appropriate relief through the exemption Licensees for 44 of the 72 plants to which Appendix R applies (plants process.
with an operating license issued prior to January 1,1979) have requested such i*
schedular relief.
j The licensees for the remaining 28 plants made submittals to meet the schedula'r requirements of 50.48(c). All of these submittals, however, were deficient in some respects.
In general, much of the information requested
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in a generic letter (81-12) dated February 20, 1981, to the licensees of all 1
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72 plants, was not provided. Therefore, additional time is being used to complete those submittals also.
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III.
- l Prior to the issuance of Aptindix R, the Maine Yankee plant had been
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l reviewed against the criteria of Appendix A to the Branch Technical Po:ition 9.5-1 (BTP 9.5-1).
The 3TP 9.5-1 was developed to resolve the lessons learned from the fire at Browns Ferry Nuclear. Plant.
It is broader in scope than
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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 I']
Plan used for the review of applications for construction pennits and operating
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licenses of new plants. The review was completed by the NRC staff and its a
fire protection consultants and a Fire Protection Safety Evaluation (FPSER)
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was issued. Some items remained unresolved. Further discourse between the licensee and the NRC staff resulted in resolution of ma'ny of these items as
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1 documented in a supplement to the FPSER issued January 21, 1981. In addition
,t by letter dated March 12, 1981 the licensee resolv,ed the remaining items, t
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other than those items subject to the requirements of Section III.G, by j
stating its intent to comply with the requirements of specified sections of j
Appendix R.
As a result of the fire protection reviews completed thusfar, 1
numerous modifications have been made to plant physical features, systems, and
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administrative controls to meet the criteria of Appendix A to BTP 9.5-1.
The
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Maine Yankee plant has been upgraded to a high degree of fire protection 4
i already and the extensive reassessment involved in this request for additional time is to quantify, in detail, the differences between what was recently j
approved and the specife requirements of Section III.G of Appendix R to 10 y
1 CFR 50.
As noted earlier the licensee has, by letter dated March 6,1981,
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requested an exemption from Section III.L of Appendix R.
Since staff denial 3,
of the licensee's March 6,1981 exemption request will be issued coincident 6
1 with issuance of this exemption, the licensee's requested schedule delay
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corresponds to a date six months from receipt of this exemption. The
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Commission has previously decided that delays in the submittal of Section 4j III.G information up to July 1,1982 are acceptable based on the responses
.s of a majority of licensees.
In Maine Yankee's case the requested exemption i
from Section III.L. regarding the availability of offsite power, has a i
N significant impact regarding the modifications necessary to meet Section f ;
III.G. Setting a response date of July 1,1982, based on oth'er licensee's l
responses, is not valid. Based on the above, we have determined that the completion of the reassessment required for Section III.G within six months 3
of receipt of this exemption is acceptable.
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l j Based on the above considerations, we find that the licensee has completed a substantial part of the fire protection features at the Maine Yankee plant in conformar;ce with the requirements of the Fire Protection Rule. We find that because of the already-completed upgrading of these facilities, there j
l is no undue risk to the health and safety of the public involved with continued operation until the completion of this reassessment required by Section III.G of Appendix R within six months of receipt of this exemption. We have determined I,
that any additional delay would not be consistent with the licensee applying its best effort at resolving and completing this issue. Therefore an exemption i
should be granted to. allow such time for completion. However, because we have found that most submittals of this reanalysis to date from other licensees
,l have not been complete; that is, not all of the information requested hy-Generic Letter 81-12 dated February 20, 1981, was provided, we are adding a condition to this Exemption that requires all such information be submitted by t.he dite granted.
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IV.
s Accordingly, the Commission has determined that, pursuant to 10 CFR 50.12, an exemption is authorized by law and will not endai.Jer life or property or the common defense and security and is otherwise in the public interest and hereby grants the following exemption 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 design _ descriptions of alternative or dedicated shutdown systems to comply with Section III.G.3, as required by 550.48(c)(5) is extended to six months from the licensee's receip-t of this i
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exemption.
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NI Provided the following condition is met:
1 The design descriptions of alternative or dedicated shutdown systems
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j 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 20,198f, and to
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1 each item in Enclosure 2 to Generic Letter 81-12, dated February 20, I
.j 1981.
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If the licensee does not meet the above condition, the licensee will be j
found in violation of 10 CFR 50.48(c) even though the submittal may be made within the time limit grar.ted by the exemption.
If such a violation occurs, q!
l imposition of a civil penalty will be considered under Section 234 of the
!l 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 l
when all inadequacies are correcte<'.
A delay in the determination c' 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-i tal, 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 Ji result in any significant environmental impact and that pursuant to 10 CFR 3
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d 51.5(d)(4) an environmental impact statement or negative declaration and environ-
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mental impact appraisal need not be prepared in connection with this action.
')j rus THE NUCLEAR REGULATORY COMMISSION l
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- i Harold R. Denton, Director
}j Office of Nuclear, Reactor Regulation Dated at Bethesda, Maryland this 19th day of May, 1982.
ENCLUSURE 3 t
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CLARIFICATION OF GENERIC LETTER l
On February 20, 1981, generic letter 81-12.was forwa;-ded to all reactor licensees The letter restated the require-l with plants licensed prior to January 1,1979.
1 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 includiTig associated non-safety circuits of redundant trains of systems necessary to achieve and JJ q
maintain hot shutdown conditions are located to determine whether the require-t Additionally, ments of Section III.G.2 of Appendix R to 10 CFR 50 were satisfied.
7 Enclosure I and Enclosure 2 of the generic letter requested additional y
.infonnation concerning those areas of the plant requiring alternative shutdown Section 8 of Enclosure 1 requested information for the systems,
,f capability.
equipment and procedures of aiternative shutdown capability and Enclosure 2 defined associated circuits and requested information concerning associated circuits for those areas requiring alternative shutdown.
4 In our review of licensee submittals and meetings with licensees, it has become f
apparent that the request for information should be clarified since a lack I
of clarity could result in the submission of either insufficient or e,xcessive Thus, the staff has rewritten Section 8 of Enclosure 1 and infonnation.
j of the February 20, 1981 generic ietter. Additionally, further i
clarification of the definition of associated circuits has been provided to
.j aid in the reassessments to determine compliance with the requirements of
,j Sections III.G.2 and III.G.3 of Appendix R.
In developing this= rewrite we have
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The attached considered the coment of the Nuclear Utility Fire Protection Group.
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! I rewrite of the Enclosures contains no new requirements but merely attempts to clarify the request for additional information.
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Licensees who have not responded to the February 20, 1981 generic letter, may choose to respond to the enclosed request for infomation.
Since the j
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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 4
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-1 mation in order to close open items (i.e., open item for. associated circuits, 1
- 5 use rewrite of Enclosure 2).
l If additional clarification is needed, please contact the staff Project 3
1 Manager for your plant.
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ATTACHMENT. 1 REWRITE OF SECTION 8 REQUEST FOR ADDITIONAL INFORMATION 4
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The following is a rewrite of the staff's request for additional infomation concerning design modification to meet the requirements of Section III'.G.3 of The following contains no new requests but is merely a rewording of 2
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Appendix R.
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Section 8 of Enclosure 1 of the February 20,'1981 generic letter,.
Identify those areas of the plant that will not meet the requirements of 1.
of Appendix R and, thus alternative shutdown will be provide'dx Section III.G.2
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, or an exemption from the requirements of Section III.G.2 of Appendix R will' be J
i provided. Additionally provide a statecent that all other areas of the plant I
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 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.
For those systems identified in '.la" fo: which alternative or dedicated b.
3 shutdown capability must be provided, list the equipment and components l
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 i
5 the system (s) or portions thereof used to provide the alternattve shutdown capability for the fire area and provide a table that lists the equipment
~i and components of the alternative shutdown system for the fire area.
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1 For each alternative system identify the function of the new 4
j circuits being provided.
Identify the location (fire zone) of the alternative shutdown equipment and/or. circuits that bypass the fire 8
4 area and verify that the alternative shutdown equipment and/or circuits are separated from the fire area in accordance with Section III.G.2.
3 A.
Provide drawings of the alternative shutdown system (s) which highlight any c.
-1 connections to the normal sh'utdown systems (P& ids for pip 1ng ano components, j
3 elementary wiring diagrams of electrical cabling).
Show the electrical j
location of all breakers for power cables, and isolation devices for l
- control and instrumentation circuits for the alternative shutdown systems i
for that fire area.
d.
Verify tihat changes to safety systems will riot degrade safety systems; (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
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mounted in should also meet the same criteria (FSAR) as other safety i
j related cabinets and panels; to avoid inadvertent isolation from the control room, the isolation switches should be keylocked or alarmed i
i in the control room if in the " local"'or " isolated" position; periodic
"),j checks should be made to verify that the switch is in the proper position for 1
I normal operation; and a single transfer switch or other new device should not be a source of a failure which causes loss of reaunaant safety s 1
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systems).
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Verify that licensee procedures have been or will be developed which describe the 1
tasks to be performed to effect the shutdown'm'ethod'.
Provide a summary j
,of these procedures outlining operator actions.
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Verify that the manpower required to perform the shutdown functions using 3
4 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.
g.
Provide a commitment to perform adequate acceptance tests of the alter-native shutdown capability.
These tests should verify that:
equipment j
operates from the local control station when the transfer or isolation switch is placed in the " local" position and that the equipment cannot be 1j operated from the control room; and that equipment operates from~ the 1
i control room but cannot be operated at the local control station when the transfer isolation switch is in the " remote". position.
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h.
Provide Technical Specifications of the surveillance requirements and
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limiting conditions for operation for that equipment not already covered by existing Technical Specifications.
For example, if new
_4 isolation and control switches are added to a shutdown system, the existing Technical Specification surveillance requirements hould 1
be supplemented to verify system / equipment functions from the alternate
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shutdown station at testing intervals consistent with the guidelines of
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Regulatory Guide 1.22 and IEEE 338.
Credit may be taken for other existing
'l 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-1 down function. The fuhctions required should be based on previous 4
i analyses, if possible (e.g., in the FSAR). such as a loss of normal 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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ATTACHMENT 2 t
o SAFE SHUTDOWN CAPABfLITY 1,
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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 following r.equirements also apply to cold s,hutdown equipment if tha licensee elects to dem'onstrate that tiie. equipment.is to be,
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free of, fire. damage. Append 6 R does allow.re'pairable damage to cold shutdown equ'ipment..,
I Using the requirements of Sect. tons III.G and III.L of Appendix R, the capa-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 equipment needed for hot shutdown:
1.
Redundant systems including cables,' equipment, and associated circuits may be separated by a three-hour fire rated barrier; or, i
2.
Redundant systems including cables, equipment and associated circuits may
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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, j
l 3.
Redundant systems including cables, encipment and associated circuits may by enclosed by a one-hour fire rated barrier.
In addition, fire detectors and an automatic fire suppression system are rdquired;
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r 2-The last option as defined by Section III.G.3 provides an alternative shutdown capability to the redundant trains damaged by a fire.
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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 l
The following discussion provides A) a definition of associated circuits for
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Appendix R consideration, B) the guidelines for protecting the safe' shutdown i
capability from the fire-induced failures of associated circuits and C) the in-t formation required by the staff to review associated circuits. The definition of associated circuits has not changed from the February 20, 1981 generic letter;"
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but is merely clarified.
It is important to note that our interest is on1y f
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 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 j
failures will be evaluated by the' staff for acceptability..
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A.
Our concern is that circuits within the fire area,will, receive fir,e damage 1 3 which can affect shutdown capability and thereby prevent post-fire safe shutdown. Associated Circuits
- of Concern are defined as those cables j
(safetyfe' lated,non-safetyrelated, Class 1E,andnon-ClasslE)that:
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- The definition for associated circuits is not exactly the same
- i as the definition presented in IEEE-384-1977.
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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
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j alternative) and the power source is not electrically protected t
from the circuit of concer,n by coordinated breakers, fuses, or l
similar devices (see diagram 2a), or I
b.
a connection to circuits of equipment whose spurious operation
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cables (redundant and alternative) and, (1) are not electrically protec'ted by circuit breakers, fuses or simi-l lar devices, or (2) will allow propagation of the fire into the common enclosure, (see diagram 2c).
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J EXAMPLES OF ASSOCIATED CIRCUITS OF CONCERN a
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aus The area barriers shown above meet i
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E 9,,,ed,9,e sg the appropriate sub-paragraphs (a-f}
cru& cou.M. a7 feel of section III.G-2 of Appendix R.
I Skaldoen Diagra.1: 2A Diagram 2B Diagram 2C 0
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The following guidelines are for protecting the shutdown capability from B.
fire-induced failures of circuits (cables) in the fire area. The guidance provided below for interrupting devices applies only to new devices installed to provide electrical isolation of associated circuits of cancern, or as The shutdown capability part of the alternative or dedicated shutdown system.
may be protected from the adverse effect of damage to associated ~ circuits of concern by the following methods:
Provide protectio'n,between the associated circuits of concern and 1.
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 redundant or To ensure that the following alternative shutdown power source.
coordination criteria are met the 'forlowing 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 of a trip of any upstream interrupting device,which will cause a loss of the common power source,
,(2) The power source shall supply t'he necessary fault current for sufficient time to ensure the proper coordination l
without loss of function of the shutdown loads.
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The acceptability of a particular interrupting device is considered i
h demonstrated if the following criteria are met:
(1) The interrupting device design shall be factory tested to l
verify overcurrent protection as designed in accordance with i
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the applicable UL, ANSI, or NEMA standards.
l (ii) For low and medium voltage switchgear (480 V and above)
I circuit breaker / protective relay periodic testing shall I
l demonstrate that the overall coordination scheme remains 4
within the limits specified in the design criteria. This testing may be performed as a series of overlapping tests.
(111) 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 shall be tested to determine that breaker drift is within that allowed by the design criteria. Breaken;should be tested in accordance with an accepted QC testing methodology
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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,
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and high reliability. Administrative controls must -insure l _. i that replacement fuses with ratings other than those Ii l';
selected for proper coordinating are not accidentally.used.
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For circuits of equipment and/or components whose spurious operation t
j would affect the capability to safely shutdown:
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(1) provide a means to isolate the equipment and/or cor.ponents from the fire area prior to the fire (i.e., remove power cables, open s
circuit breakers); or
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i j-(2) provide electrical isolation that prevents sputious operation.
d, Potential isolation devices include breakers, fuses, ampli-f ers, control switches, current XFRS, fiber optic couplers, relays and transducers; or 4
i (3) provide a means to detect spurious operations and then proce-
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dures 'to defeat the maloperation of equipment (i.e., closure of the block valve if PORV spuriously operates, opening of the breakers to remove spurious operation of safety injei: tion);
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j, For common enclosure cases of associated circuits:
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l (1) provide appropriate measures to prevent propagation of the fire; and 1l (2) provide electrical protection (i.e., breakers, fuses or similar devices) 1 We recognize that there are differ.ent' approaches which may be used to 1
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ii reach the same objective of determining the interaction of associated l
i circuits with shutdown systems. One approach is to. s. tart 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 l
outside the fire area. We have entitled this' approach, "The Fire Area
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1 Approach." A second approach which we-have named "The Systems Approach" 1
j would be to define the shutdown systems around a fire area and then determine a
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'1 those circuits that are located in the fire area that are associated j
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 selec.ted by the licensee.
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FIRE AREA APPROACH I,
1.
For each fire 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
,i alternative or dedicated shutdown method:
Provide a table that lists all the power cables in the fire a'rea a.
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that connect to the same power supply of the. alternative or dedicated shutdown method and the func' tion of each power cable listed (i.e.,'powerforRHRpump).
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b.
Provide a table that lists all the cables in the fire area that l
were considered for possible spurious operation which would adversely affect shutdown and the function of each cable listed.
.4 Provide a table that lists, all the cables in the fire area that c.
j share a common enclosure with circuits of the alternative or
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dedicated shutdown systems and the function.of each cable' listed.
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d.
Show that fire-induced failures (hot shorts, open circuits or shorts to ground) of each of the cables. listed in a; b, and c will 1
1 not prevent operation or cause maloperation of the alternative
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.or dedicated shutdown method.
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For each cable listed in a, b and c where new electrical isolation has e.
been provided.or modification to' existir.g electrical isolation has been made, provide detailed electrical schematic drawings that
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show how each cable is isolated from the fire are-d.
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SYSTEMS APPROACH i
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 s,
i circuits will not prevent operation or cause maloperation of the i
alternative or dedicated shutdown method:
Describe the methodology used to assess the potential of associated a.
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circuit adversly affecting the alternative or dedicated shutdown.
The description of the methodology sho'uld include the methods 2
used to identify the circuits which share a common power supply or a comon enclosure with the alternative or dedicated shutdown l
system and the circuits whose spurious operation would affect i
i shutdown. Additionally, the description should include the
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methods used to identify if these circuits are associated circuits of concern due to their lo, cation in the fire area.
b.
Provide a table that lists all associated circuits of con,cern i
located in the fire area.
Show that fire-induced failurds (hot shorts, open circuits ar c.
l shorts to ground) of each of the cables listed in b will not
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prevent operation or cause maloperation of the alternatite or f
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dedicated shutdown method.
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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 office,s where all the i
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tables and drawings generated by this metho'[olo'gy appr,oac_h i
for the associated circuits review may be audited to verify,the i,
information provided above.
- d HIGH-LOWPRESSUREfNTERFACE
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For either approach chosen the following concern dealing with high-low.
' pressureintehfaceshouldbeaddressed.
J 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 require compliance with the recomnendations of Branch Technical Position RSB 5-1.
Thus, the interface most likely consists of two redundant and independent motor
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operated valves. These two motor operated valves and their associdted i
cables may be subject to,a single f. ire hazard.
It is our u ncern that this single fire could cause the two valves to open resulting in a fire initiated LOCA through the high-low pressure system
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interface. To assure that this interface and other high-low.
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pressure interfaces are adequately, protected from the effects of a
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single fire, we require the following information:
4 a.. Identify each high-low pressure interface that uses redundant 1]
electrically controlled dev' ices'(such as two series motor operated 3[
valves) to isolate or preclude rupture of any primary coolant' j
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.
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For each case where adequate separation is r.ct provided, shot: tSct i
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fire induced failures (hot short, open circuits or short to ground)
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of the cables will not cause maloperation and result 1n a LOCA.
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CRITERIA FOR EVALUATING i
EXEMPTIONS TO SECTION III G OF APPENDIX R j
OF 10 CFR PART 50 1
Paragraph 50.48 Fire Protection of 10 CFR Part 50 requires that all i
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 with 1
the requirements of Section III.G.
Section III.G is related to fire
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protection features for ensuring that systems and associated-circuits
,used to achieve and maintain safe shutdown are free of fire damage.
1 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.
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The general criteria for accepting an alternative fire protection configur-1 ations are the following:
'tl-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 is limited such that it can be iepaired within a reasonable time (minor repairs with components stored on-site).
Fire retardant coatings are not used as fire k arriers.
Modifications required to meet Section III.G would.not enhance k
fire protection safety above that provided by either existing or j
proposed alternatives.
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l Modifications required to meet Section III.G would be detrimental j
to overall facility safety.
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Because of the broad spectrum of potential configurations for which exemptions may be, requested, specific criteria that account for all of the parameters that are important to fire protection and consistent with i
safety requirements of all plant-unique configurations have not been j
devel oped.
However, our evaluations of deviations froc.these require-ments in our grevious reviews and in the request's for III.G exemptions 9i received to date have identified some recurring configurations for which j
specific criteria have been developed.
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'l A passive Section III.G.2 accepts three methods of fire protection.Where a fixed barrier 3-hour fire barrier should be used where possible.
cannot be !.istalled, an automatic suppression system in combination with
,1 a fire barrier or a separation distance free of combustibles is used if j
the configurations of systems to be protected and in-situ combustibles are such that there is reasonable assurance that the protected systems will If this latter condition is not met, alternative-shutdown capa-survive.
bility is required and a fixed suppression system installed in the fire It 'is area of concern, if it contains a large concentration of cables.
essential to remember that these alternative requirements are not deemed a
However, they provide adequate protection for those l
to be equivalent.
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, configurations in which they are accepted.
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Wheri the fire protection features 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 adequate balance between the different features. Strengthening any one can compensate in some measure for weaknesses, known or unknown in others.
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The adequacy of. fire protection for any particular piant safety system or
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i, area is determined by analysis of the effects of postulated fire relative to maintaining the ability to safely shutdown the plant and minimize radio-During thes,e active releases to the environment in the event of a fire.
'i evaluations it is necessary to consider the two-edged nature of fire protection features recognized in General Design Crite j
An evaluation must be made for each fire area for which an exemption During these evaluations, the. staff considers the following is requested.
j parameters:
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'A.
Area Description 1
walls, floor, and ceiling construction ceiling ~ height 0
1 room Volume
'l ventilation j
congestion
'i B.
Safe Shutdown Capability
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number of redundant systems in area j
whether or not system or equiment is required for hot shutdown type of equipment / cables involved repair time for cold shutdown equipmnt within this area
,j separation between redundant components and in-situ concentration of combustibles alternative shutdown capability
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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.
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.
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, have 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.
Fix'ed fire barriers 'less than 3-hour rating.
2.
Fire barrier without an automatic fire suppression sys~ tem.
Less than 20 feet separation of cables with fire propagation -
3.
retardants (e.g., coatings, blankets, covered trafs) and an automatic suppression system.
For large open areas with few components to be protected and few in-situ 4.
combustibles, no automatic suppression system with separation as in Item
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3 above.
5.
No fixed suppression in the contr'01 room.
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Jhs fixed suppression in areas without a large concentration of cables for
.which alternative shutdown capability has been provided.
Our fire research test program is conducting tests to provide information
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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 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.
4 Exemptions may be granted for a lower rating (e.g., one hour or two hou's) r The fire where the fire loading is no more than 1/2 of the barrier rating.
rating of the barrier shal1~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 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
'have 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 combustib1'es will not occur or will be delayed sufficiently to ensure adequate time for detection and' suppression.
l Distance above a floor level exposure fire-and below ceiling assures 2.
that redundant systems will not be simultaneously subject to an unasceptable temperature or heat flux.
The ommission of an automatic suppression system may be deemed acceptable B.
where:
1.
Distance above a floor level exposure fire and below ceiling assures that redundant systems will not be simultaneously subject to an i
unacceptable temperature or heat flux.
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The fire area is required to be manned continuously by the provisions in the Technical Specifications.
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