ML20053E466
| ML20053E466 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 05/10/1982 |
| From: | Harold Denton Office of Nuclear Reactor Regulation |
| To: | VERMONT YANKEE NUCLEAR POWER CORP. |
| Shared Package | |
| ML20053E467 | List: |
| References | |
| GL-81-12, NUDOCS 8206080195 | |
| Download: ML20053E466 (37) | |
Text
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7590-01 o
NUCLEAR REGULATORY COMMISSION In the Matter of
)
)
VERMONT YANKEE NUCLEAR POWER
)
Docket No. 50-271 CORPORATION
)
(Vermont Yankee Nuclear Power
)
Station)
)
EXEMPTION I.
The Vermont Yankee Nuclear Power Corporation (the licensee) is the holder of Facility ' Operating License No. DPR-78 which authorizes operation of the Vermont Yankee Nuclear Power Station.
The 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 is a boiling water reactor at the licensee's site located near Vernon, Vermont.
II.
On November 19, 1980, the Commission published a revised Section 10 CFR 50.48 and a new Appendix R to lQ CFR 50 regarding fire protection features of nuclear power plants (45 FR 76602). The revised Section 50.48 and Appendix R became effective on February 17, 1981.
Section 50.48(c) established the schedules for satisfying the provisions of Appendix R.
Section III of Appendix R contains fifteen subractions, lettered A through'0, each of which specifies requirements for a particular aspect of the fire protection features at a nuclear power plant. One of these fifteen subsections III.G., is the subject of this Exemption.
Section III.G. specifies detailed requirements for fire protection of the equipment used for safe shutdown.by means of separation and barriers (III.G.2).
If the requirements for separation and barriers could DESIGutsp 03p0IltE hbbbOC O!bbbbh1 Certified By F
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- not be met in an area, alternative safe shutdown capability, independ'ent of that area and equipment in that area, was required (III.G.3.).
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 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 completion 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.
By letter dated February 13, 1981, Vermont Yankee Nuclear Power Corporation, among other things, requested exemption from 10 CFR 50.48(c) with respect to the requirements of Section. III.G of Appendix R in order to extend from March 19,1981, ~
to July 30, 1981, the date for submittal of design descriptions of alternative or dedicated shutdown systems to comply with Section III.G.3.
When this Fire Protection Rule was approved by the Commission, it was understood that the time required for each licensee to reexamine those previously-approved configurations at its plant to determine 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 detennine whether the existing configuration provided sufficient fire protection.
If it did, a basis had to be formulated for an exemption request.
If it did not, modifications to either meet the requirements of Appendix R or to provide some other acceptable configuration,.that could be justified for an exemption, had to be designed. Where fire protection features alone could not ensure pro-tection of safe shutdown capability, alternative safe shutdown capability had m
to be designed as required by Section III.G.3. of Appendix R.
Depending upon the extensiveness and number of the areas involved, the time required for this reexamination, reanalysis and redesign could vary from a few months to a l
year or more.
The Commission decided, however, to require one, short-term date for all licensees in the interest of ensuring a best-effort, expedited completion of ' compliance with the Fire Protection Rule, recognizing that there would be a number of licensees who could not meet these time restraints but who could then
. request appro'priate relief through the exemption process.
Licensees for 44 of the 72 plants to which Appendix R applies (plants with an operating license issued prior to January 1,1979) have requested such schedular relief.
The licensees for the remaining 28 plants made submittals to meet the schedular requirements of 50.48(c). All of these submittals, however, were deficient in some respects.
In general, much of the information requested
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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 complete those submittals also.
III.
Prior to the issuance of Appendix R, the Vermont Yankee Nuclear Power Station had been reviewed against the criteria of Appendix A to the Branch Technical 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, formed the nucleus of the criteria developed further in Appendix R and in its present, revised form constitutes the section of the Standard Review Plan used for the review of applications for construction permits and operating licenses of new plants. The review was completed by the NRC staff O
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- and its fire protection consultants and a Fire Protection Safety Evaluation (FPSER) was issued.
A few items remained unresolved.
Further discourse between the licensee and the NRC staff resulted in resolution of these items,as documented in a supplement to the FPSER. The FPSER and its supplement supported the issuance of amendments to the operating license of the Vermont Yankee Nuclear Power Station 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 completed.
Therefore, the Vermont Yankee Nuclear Power Station has been upgraded to a high degree of fire protection already and the extensive reassessment involved in this request for 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.
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Based on the licensee's request for exemption, all other applicable sub-sections of Appendix R would be met on' the schedules required by.10 CFR 50.48(c).
As mentioned eariier there are 14 other subsections which contain criteria for other aspects of fire protection features., One of these,Section III.L., provides the criteria for Alternative Safe Shutdown capability and thus affects the final reassessment and redesign,-if necessary, of this feature at the Vermont Yankee Nuclear Power Station.
Nevertheless, this means that compliance with the remaining applicable sections of Appendix R have been or will be completed on
'or before the implementation dates required by the Fire Protection Rule.
O ermont Yankee Nuclear Power Station - Operating License DPR-28 V
Amendment 43 supported by FPSER issued January 30, 1978 Letter from NRC to Vermont Yankee Nuclear Power Corporation supported by Supplement to FPSER issued October 24, 1980.
Based on the above considerations, we find that the licensee has completed a substantial part of the fire protection features at Vermont Yankee Nuc1' ear Power Station 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 Section III.G.
We find that because of the already-completed upgrading of the facility, there i
is no undue risk to the health and safety of the public involved with continued
. operation until the completion of this reassessment on July 31, 1981. Therefore, an exemption 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-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 exenption that requires all such information to be submitted
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by the date granted.
IV.
Accordingly, the Commission had 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 o' herwise in the public interest and hereby t
grants the following exemption with respect to the requirements of Section III.G.
of Appendix R to 10 CFR 50:
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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.
50.48(c)(5) is extended to July 31, 1981.
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 l
each item in Enclosure 2 to Generic Letter 81-12, dated February 20, l
'1 981.
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, If the licensee does not meet the above condition, 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 sutaittals falling due near. the same time, will not relieve the licensee of the responsibility for completeness of
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the sutmittal, nor will such delay cause any penalty that may be imposed to be mitigated.
The NRC staff has ' determined that the granting of this exemption will not result in any significant environmental impact and that pursuant to 10 CFR 51.5(d)(4) an environmental impact statement or negative declaration and environ-mental impact appraisal need not be prepared in connection with this action.
FOR THE NUCLEAR REGULATORY COMMISSION MOl Harold R. Denton, Director Office of Nuclear Reactor Regulation Dated at Bethesda, Maryland this 10th day of May 1982
e e,
. CLARIFICATION OF GENERIC LETTER On February 20, 1981, generic letter 81-12 was forwarded to all reactor licensees with plants licensed prior to January 1,1979.
The letter restated the require-ment of Section 50.48 to 10 CFR Part 50 that each licensee would be re, quired to reassess areas of the plant where cables or equipment including associated non-safety circuits of redundant trains of systems necessary to achteve and maintain hot shutdown conditions-are located to determine whether the recjuire-
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ments of Section III.G.2 of Appendix R to 10 CFR 50 wsre satisfied.
Additionally,
. and Enclosure 2 of' the generic letter requested additional
.infomation concerning those areas of the plant requiring alternative shutdown s
. capability.
Section 8 of Enclosure 1 requested information for the systems, equipment and procedures o~f 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 m
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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 of the Fsbruary 20,19S1 generic letter.
Additionally, further clarification of the definition of associated circuits ~ has been provided to aid in the reassessments to determine compliance w'ith th'e requirements of Sections III.G.2 and III.G.3 of Appendix R.
In develning this rewrite we have.
considered the-coment of the Nuclear Utility Fire Protection Group.
The. attached rewrite of the Enclosures contains no new requirements but merely attempts to clarify the request for additional information.
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t 2-Licensees who have not responded to the February 20, 1981 generic letter, 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 (14e., associated circuits),
may choose to respond to pertinent sections of the enclosed request for infor-mation in order to close open items (i.e., open item for. associated circuits, use rewrite of Enclosure 2).
If additional clarification is needed, please contact the staff Project Manager for your plant.
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.g REWRITE OF SECTION 8 REQUEST FOR ADDITIONAL INFORMATION l
The following is a rewrite of the staff's request for additional infomation concerning design modification to meet the requirenents of Section III.G.3 of i
Appendix P..
The following contains no new requests but is merely a rewording of I
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Section 8 of Enclosure 1 of the February 20, 1981 generic letter.
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Identify those areas of the plant that will not meet the requirements of Si.ction III.G.2 of Appendix R and, thus alternative shutdown will be provided or an exemption from the requirements of Sec' tion III.G.2 of Appendix R will be
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I provided. Additionally provide a statement that all other areas of the plane 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 alternat'ive shutdown system (s) provide a complete set of responses to the following requests for
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each fire area:
List the system (s) or portions thereof used to provide the shutdown a.
capability with the loss of offsite power.
-i b.
For those systems identified in "la" for which alternative or dedicated j
shutdown capability must b'e provided, list the equipment and components 3
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of the~ normal shutdown system in the fire area and identiff the functions of the circuits of the normal shutdown system in the fire area (power to what equipment, control of what components and instrumentation). Describe the system (s) or portions thereof used to provide the alternative shutdown capability for the fire area and provide a ' table that lists the equipment and components of the alternative shutdown system 'for the fire area.
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'W For each alternative system identify the functi~on of 1.he new circuits being provided.
Identify the location (fire zone) of the-alternative shutdown equipment and/or. circuits that bypass the fire area and verify that the alternative shutdown equipment and/or circuits are separated from the fire area in accordance with Section III.G.2.
Provide drawings of the alternative shutdown system (s) which highlight any c.
connections to the normal shutdown systems (P& ids for piping ano components,.
elementary wiring diagrams of electrical cabling).
Show the electrical location of all breakers for power cables, and isolation devices for control and instrumentation circuits for the alternative shutdown systems for that fire area.
d.
Verify that changes to safety systems will not degrade safety syste's; m
(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 it 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 shoul,d be keylocked or alamed in the control room if in the " local" or " isolated" position; periodic checks should be made to verify that the switch is in the proper position for nomal operation; and a single ~ transfer switch or other new device should not be a source of a failure which causes loss of recuncant safety'-
systems).
Verify that licensee procedures have been or will. be develo' ed which describe the e..'
p tasks to be perfomed to effect the shutdown method.
Provide a summary of these. procedures outlining operator actions.
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. f.. Verify that the manpower required to perform the shutdosn functions the procedures of es as well as to provide fire brigade members to fight i -
the fire is available as required by the fire brigade technical speci-fications.
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9 provide a commitment to perform adequate acceptance tests of the alter-y native shutdown capability.
These tests should verify that:
equipment operates from the local control station when the transfer or isolation
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,.1 switch is placed in the " local" position and that the equipment cannot be i
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operated, from the control room;.and that equipment operates from the i
control room but cannot be operated at the local control s'tation when q
the transfer isolation switch is in the " remote" position.
'4 h.
Provide Technical Specifications of the surveillance requirements and limiting conditions for operation for that equipment not already '
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.y covered by existing Technical Specifications.
For, example, if new isolation and control switches are added to a shutdown system, i
'l 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 guidelines of
' Regulatory Guide 1.22 and IEEE 338.
Credit may be taken for other existing i
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-
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down function. The functions required should be based on previous
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analyses, if possible (e.g., in the FSAR), such as a loss of nomal ac
..l 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 dev. eloped.
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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. SAFE SHUTDOWN CAPABILITY i
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 b[
free of fire damage.
The followlng..r.equirements also apply to cold s,hutdown i
j equipment if tha licen'see elects to deEonstrate that th' e.equipgent. is to be,
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free of fire. damage. AppendUc R does allow.rejairable damage to cold shutdown d
ecutoment.
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Using,the requirements of Sections III.G and III.L of Appendix R, the capa-j bility'to achieve hot shutdown must exist given a fire in any area of the plant in conjunction with a loss of offsite power for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
Section III.G of Appendix R provides four methods for ensuring that the hot shu'tdown capa-bility is protected from fires. The first three options as defined in Section.
III.G.2 provides methods for protection from fires of equipnte.nt needed for t
hot shutdown:
1.
Redundant systems including gables, equipment, and ssociated circuits a
may be separated by a th'ree.-hour fire rated barrier; or,
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I 2.
Redundant systems.tncluding cables, equipment and associated circuits may i
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be separated by a horizontal distance of more than 20 feet with no inter-1 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 i
be enclosed by a one-hour fire rated barrier.
In additien, fire detectors and an autcmatic fire suppression system are requ' ired.
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- The last option as defined by Section III.G.3 provides an alternative shutdown capability to the redundant trains damaged by a fire.
4.
Alternative shutdown equipment must be independent of the cables, equip-1 ment and associated circuits of the redundant systems damaged by the fire.
J,j Associated Circuits of Concern
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The following discussion provides A) a definition of associated circuits for c
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Appendix R consideration, B) the guidelines for protecting the safe' shutdown
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j capability from the' fire-induced failures of associated circuits and C) -the in-3
'l formation required by the staff to review associated circuits. The definition' of associated circuits has not changed from the February 20, lgal generic letter; but is merely clarified.
I.t is important. to note that our interest is only
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with those circuit (cabies) whose fire-induced failure could affect shutdown.
i The guidelines for protecting the safe shutdown capability from the fire-induced 3
failures of associated circuits are not.recuirements. These guidelines should be used only as guidancs when needed. These guidelines do not limit the alter-i natives available to the licensee for protecting the shutdown capability.
All proposed methods for protection o' the shutdown capability from fire-induced f
failures will be evaluated by the staff for accepta'bility.
-l1 A.
0ur concern is that 'ircuits within the fire area,will,. receive fire damage c
e which can affect shutdown capability and thereby prevent post-fire safe
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shutdown. Associated Circuits
- of Concern are" defined as 'those cables (safety related, non-safety related, Class lE,' and non-Class lE) that:
- The definition for associated circuits is not exactly the same
'as the definition presented in IEEE-384-1977.
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1.
Have a physical separation less than that required by Section III.G.2 of Appendix R,.and; j
2.
Have one of the'following:
-t a.
a common power source with the shutdown equipment (redundant or alternative} and the power source is not electrically protected
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from the circuit of concer.n by coordinated breakers, fuses, or
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s'imilar devices (see diagram 2a), or i
j b.
a connection to circuits of equipment whose spurious operation
.1 would adversely affect the shutdown capability (e.g., RHR/RCS
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. isolation valves, ADS valves, PORVs, stear generator atmospheric dump valves, instrumentation, steam bypass, etc.) (see diagram 2b), or a common enclosure (e.g., raceway, panel, junction) with the shutdown cj
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cables (redundant and alternative) and, i,
'i (1) are not electrically ' protected by circuit breakers, fuses'or simi ~
lar devices, or (2)will allow propagation of the fire into the connon enclosure, (see diagram 2c).
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EXAMPLES ~0F ASSOCIATED CIRCUITS OF CONCERf!
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E eup,,ie,d wpse spadmo The area barriers shown above meet the appropriate sub-paragraphs (a-f) o u-b1 coaM. a/Tec/
of section III.G-2 of Appendix R.
r skuddo.an Diagram 2A Diagram 20 Diagram 2C i
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The following guidelines are for protecting the shutdown capability from fire-induced failures of circuits (cables) in the fire area.
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.The guidance provided below for interrupting devices applies only to 'new devices installed to provide electrical isolation of associated circuits of concern, or as A
part of the alternative or dedicated shutdown system.
Previous coordina-
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tion analyses need not be reanalyzed; however, breakers that were not Q1; included in previous reviews, will require a coordination analysis. The 3
1 shutdown capability may be protected from.the adverse effect of damage to 3
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..j associated circuits of concern bv the following methods:
1.
Provide protection between the associated circuits of concern and the ' shutdown circuits as per Section III.G.2 of Appendix R, or E
2.
a.
For a comon power source case of, associated circuit:
j Provide load fuse / breaker (interrupting devices) to feeder fuse / breaker coordination to prevent loss of the redundant or j
alternative shu,tdowi1 power source. To ensure that the following coordination criteria are met the 'foliowing should apply:
1 t i (1) The associated c'ircuit of concern interrupting devices '
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(breakers or fuses) time-overcurient trip characteristic for all circuits faults should cause the interrupting device to interrupt the fault c'urrent prior to initiation
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of a trip.of any upstream interrupting device which'will cause a loss of the common power. source, (2) The power source shall supply the necessary fault current for sufficient time to ensure the proper coordination j
without loss of function of the shutdhn loads.
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l The acceptability of a particular interrupting device is considered demonstrated if the following criteria are met:
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(i) The interrupting device design shall be factory. tested to
.i verify overcurrent protection as designed in accordance with 1
the applicable UL, ANSI, or NEMA standards.
,j (ii) For low and medium voltage 'switchgear (480 V and above) 1
.I circuit breaker / protective relay periodic testing shall demonstrate that the overall coordination scheme remains' within the limits specified in the design criteria. This te: ting may be performed as a series of overlapping ' ests.
t (iii) Molded case circuit breakers shall periodically be manually exercised and inspected to insure ease of operation..On a rotating refueling outage basis a sample of these breakers i
shall be tested to determine that breaker drift is~ within
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that allowed by the design criteria. Breakers should be tested in accordance.with an accepted QC testing methodology
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i such as MIL STD 10 5 D.
(iv)
Fuses when used as interrupting devices do not require periodic testing. Administrative controls must insure j
that replacement fuses witil ratings o'ther than those selected for proper coordination are not accidentally used.
l b.
For circuits of equipment and/or components whose spurious operation would affect the capability to safely shutdown:
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f (1) provide a means to isolate the equipment and/or components from the fire area prior to ti:e fire (i.e., remove power cables, open circuitbreakers);or i
4 (2) provide electrical isolation that prevents spurious operation.
4 Potential isolation devices include breakers, fuses, ampli-ii,j fiers, control switches, current XFRS, fiber optic couplers, y
relays and. transducers; or 1
(3) provide a means to detect spupious operations and then proce-dures to defeat the maloperation of equipment (i.e., closure of the block valve if p0RV spuriously, operates, opening of the breakers to remove spurious operation of safety injection);
c.
For common enclosure cases of asso.ciated circuits:
(1) provide appropriate measures to prevent propagation of the fire; and, 5
(2) provide electrical protection (i.e., breakers, fuses or i
similar devices)
C.
We recognize that there are different approaches which may be used to reach the same objective of determining the interaction of associated circuits with shutdown systems. One approach 1,s 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 outside the fire area. We have entitled this approach "The Fire Area Approach." A second approach which we have named "The Systems-Approach"
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would 'be to define the shutdown systems around a fire area and then determine
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.i those circuits that are located in the fire area that are associated with the shutdown system. We have prepared two sets of requests for i
informatica, one for each approach. The licensee may choose to respond I
j to either set of requests depending on the approach selected by the licensee.
FIRE AREA APPROACH TI 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 a
1 following information is required to demonstrate that associated i
circuits will not prevent operation or cause maloperation of the.
i alternative or dedicated shutdown method:
Provide a table that lists al'1 the power cables in th'e fire area a.
that conr: set 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 1
were considered for possible spurious operation which would adversely I
affect shutdown and the function of each cable listed.
Provide a table that lists all the cables in the fire area that c.
share a common enclosure with circuits of the alternativ.e or i
dedicated shutdown systems and the function of each cable listed.
d.
Show that fire-induced failures (hot shorts, open circuits or shorts to ground) of each of the cables listed in af b, and c will i
I not prevent oper: tion or cause maloperation 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 e.
been provided or modification to existing electrical isolation has been made, provide detailed electrical schematic drawings that show how each cable is isolated from the fire area.
SYSTEMS APPROACH 1.
For each area where an alternative or dedicated shutdown method, in
' accordance with Section III.G.3 of Appendix R is provided, the following information is required to demonstrate that associated
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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 capability.
The description of the methodology should include the methods used to identify the circuits which shari a common power supply or a common enclosure with the alternative or dedicated shutdown system and the circuits whose spurious operation would affect shutdown. Additionally, the description should include the
' methods used to identify if these circuits are associa.ted 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 fire area.
Show that fire-induced failures (hot shorts, open. circuits or c.
shorts to ground) of each of the cables listed in b,will not prevent operation or cause maloperation of the alternatife or.
dedicated shutdow, method.-
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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.
e.
Provide a location at the site or other offices where a'll the tables and drawings generated by this cethodology approach for the associated circuits review may be audited to verify ~ the information provided above.
HIGH-LOW PRESSURE INTERFACE For either approach chosen the following concern dealing with high-low-pressure interface should be addressed.
2.
The residual heat removal system is generally a low pressure. system I
that interfaces with the high pressure primary coolant system. To preclude a LOCA through this interface, we require compliance with the recommendations of Branch-Technical Position R R.5-1.
Thus, the interface most likely consists of two redundant and independent motor
.I operated valves. These two motor operated valves and their associdted..-
cables may be subject to a single f. ire hazard.
It is our concern that this single fire could cause the two valves to open resulting.in a fire initiated LOCA through the high-low pressure system k
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:
Identify each high-low pressure interface that uses redundant a..
t electrically controlled devices (such as two series. motor operated valves) to isolate or preclude rupture of any primary coolant t
boundary.
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For each set of redundant valves identified in a.,
verify the redundant cabling (power and control) have adequate physical separation as required by Section III.G.2 of Appendix R.
- 1 For each case where adequate sop.rction is net previdej, shot: that c.
fire induced failures (hot short, open circuits or short to ground) y, of the cables will not cause maloperation and result in a LOCA.
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CRIT'ERIAFOREVA(UATING EYEMPTI0tdTOSECTIONIIIGOF$PPENDIXR k
OF 10 CFR PART 50 nragraph 50.48 Fire Protection of 10 CFR Part 50 requires that all nuclear poner 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 the requirements of Section III.G.
Section III.G is related to fire protection features for ensuring that systems and associated circuits used to achieve and maintain safe shutdown are free of fire damage.
Fire protiction configurations must eithe.r meet the specific require-ments of Section III.G or an alternative fire protection configuration -
must bg justified by a fire hazard analysis.
The general criteria for accepting an alternative fire protection configur-
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ations are the following:
The alternative assures that one train of equipment necessary to achieve hot shutdown from either the control room or emergency control stations is free of fire damage.
The alternative assures that fire damage to at least one train. of equipment necessary to achieve cold shutdown is limited such that it can be repaired within a reasonable time (minor repairs with components stored on-site).
Fire retardant coatings are not used as fire bhrriers.
Modifications required to meet Section III.G would not enhance fire protection safety above that provided by either existing or propos9d alternatives.
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Modifications required to meet Section III.G would be detrimental to overall facility safety.
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 safety requirements of all plant-unique confi urations have not been developed.
However, our evaluations of devic.. ions from these require-ments in cur previous reviews and in the requests for III.G exemptions' received to date have identified some recurring configurations for which
-specific criteria have beer, developed.
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.Section III.G.2 accepts three methods of fire protection.
A passive 3-hour fire barrier should be used where possible.
Where a fixed barrier cannot be installed, an automatic suppression system in combination with a fire barrier or a separation distance free of combustibles is used if the configurations of systems to be protected and in-situ ccmbustibles' are such that there is reasonable assurance that the protected syste'ms will survive.
If this latter condition is not met, alternative shutdoyn capa.-
bility is required and a fixed suppression system installed in the fire area of concern, if it contains a large concentration of cables..
It is ess'ential to remember that these alternative requirements are not deemed to be equivalent.
However, 'they provide adequate protection for those configurations in which they are accepted.
When the fire protection features of each fire area are evaluated, the
. whole system of such features must be kept in perspective.
The defense-in-depth principle of fire protection programs is aimed at acnieving an adequate balance between the different features.
Strengthening any.one can compensate in some measure for weaknesses,.known or unknown in others.
The adequacy of fire protection for any particular plant safety sy. stem or area is determined by analysis of the effects of postulated fire relative to maintaining the ability to safely shutdown the plant and minimize radio-active releases to the environment in the event of a fire.
During thes.e.
evaluations it is necessary to consider the two-edged nature of fire
. protection features recognized in General Design Criterion 3 namely, fire protection should be provided consistent with other safety considerations.
An evaluation must be made for each fi.re area for which an exem'ption is requested.
During these evaluations, the staff considers the following parameters:
'A. ' Area Description walls, floor, and ceiling ' construction ceiling height room volume ventilation congestion B.
Safe Shutdown Capability number of redundant systems in area thether or not system or equiment is. required for hot shutdown type of equipment / cables involved repair time for cold shutdown equipmnt within th'is area separation between redundant components and in-situ concentration of combustibles alternative shutdown capability a
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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 Existi~ng or Committed fire detection systems fire extinguishing systems ho,s,e 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 wherethere are cables.
If necessary, a team.of. experts, including a fire protection engineer, will visit the site to determine the existing circumstances.
This visual in3pection is also considered in the review process.
The majority of the III.G exemption requests received to date are being deriied because they lack specificity.
Licensees have not identified the extent of the exemption requested, have not provided a. technical basis For t'he request and/or have not provided a specific description of the alternative.
We expect to receive requests for exemption of the follgwing nature:
I 1.
Fiied fire barriers'less than 3-hour rating.
2.
Fire barrier without an automatic fire suppression system.
3.
Less than 20 feet separation of cables with fire propagation retardants (e.g., coatings, blankets, covered trays) and an automatir suppression system.
4.
For large open areas with few components to be protected and few in-situ combustibles, no automatic suppression system with separation as in Item 3~above.
5.
No fixed suppression in the contr'ol room.
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6.
No fixed suppression in areas without a large concentration'of cables for which alternative shutdown capability has been providq4 Our fire research test program is conducting tests to provide information that will be useful to determine the boundary of acceptable conditions for fire protection configurations which do not include a fire rated barrier.
Basedondehiationsrecentlyapprohed,s"ecificcriteriaforpertain recurring configurations are as follows:
Fir 6 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 hours) i 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.
The fire 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.
be water or gas.
The suppressant may Exemptions may be granted for donfigurations of redundant systems.which hav~e compensating features.
For example:
A.
Separation distances less than 20 feet may be deemed acceptabi-where:
1.
Fire propagation retardants (i.e., cable coatings, covered trays, conduits, or min.eral wool blankets) assure that fire propagation through in-situ combustibles will not occur or will be delayed sufficiently to ensure adequate time' for detection and suppression.
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2.
Distance above a floor level exposure fire and below ceiling. assures that redundant systems will net be simultt neousl.y subject to.an una.qceptable temperature or heat flux.
2.
The ommission of an automatic suppression system may b' deemed ac'ceptable where:
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Distan:e above a floor level exposure fire and belop ceiling assures i
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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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REQUEST FOR ADDITIONAL INFORMATION 1.
Confirm that the capability will be provided to achieve cold shutdown-within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> as required by Appendix R of 10 CFR Part 50 -
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2 Please commit and provide a schedule for developing and implementing the procedures for shutdown operation.
These procedures should address manpower requirement and manual actions to accomplish shutdown.
3.
Identify the type of isolation proposed for the RCIC control and instru-mentation circuits, the diesel generator 125 volt D.C. loads, the RHR,
loads, the service water load and the uninterruptable power supply loads.
Details and schematics should be provided for the above.
4.
Provide a point-by-point response with respect to interactions of associated circuits as outline in Enclosure 2 of the February 20, 1981 letter (including all requested tables).
5.
In your submittal dated July 31, 1981, the high-low pressure interface was identified as two valves in the RHR system and two valves for the reactor head vents. However, you did not respond to the request to list the cables involved and to identify cables separation in accordance with Section III.G.2 of Appendix R.
Please provide the information requested in Enclosure 2 Question 2 of the February 20, 1981 letter.
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POST FIRE SHUTDOWN CAPABILITY VERMONT YANKEE PLANT Project Engineer - E. A. MacDougall November 24, 1981
1.0 INTRODUCTION
1.1 The licensee's submittals that were reviewed for this report are those dated June 3,1980, November 24, 1980, Februa ry 13, 1981, March 18, 1981, and July 31, 1981.
There was a conference call on November 20, 1981, see a,ttached memorandum regarding this call.
1.2 T'1e Safety Evaluation Report (SER) for the Vermont Yankee Nuclear Power Plant, Nuclear Regulatory Commission, January 19, 1978 requested that the licensee provide a summary of the analysis that demonstrates that safe shutdown systems can be placed in operation independent of fire damage to electrical circuits in either the control room, cable spread-ing area, or the switchgear room.
Procedures for manual operations were requested.
The submittals reviewed by Brookhaven' National Laboratory (BNL) address-ed the requiremer.ts of the SER.
However, we found that there were vari-ances between the submittals and the requirements of Section L of Appen-dix R to 10 CFR Part 50.
The variances are reviewed in this report.'
1.3 The Vermont Yankee plant is a BWR rated at 514-MWe.. The piant is owned
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and operated by the Vermont Yankee Nuclear Power Corporation and went into commercial operation in 1972.
2.'O REVIEWANDEVALUATION
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_.1 Section III G.- Fire Protection and Safe Shutdown Caoability 2
2.1.1 Systems Used for Post. Fire Safe Shutdown For post fire safe shutdown the licensee proposes to use the CRD system to control reactivity; the RCIC system for reactor coolant inventory and decay heat removal; the safety relief valves, and RHR system will also be used for decay heat removal.
For. suppression pool cooling, the RHR system will be used with the service water system providing cooling.
For cold shutdown the RHR system will.be used in the shutdown cooling mode.
2.1.2 Type of Fire Protection Provided
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In their submittals for post fire shutdown capability, the licensee ad-oressed the following fire protection methods:
e a.
Switchgear Room Existing CO2 fire protection system to be converted into two systems.
A one-hour fire barrier will be installed around the feed cables to MCC 9B as they pass through the fire area containing 4160 V busses 1 and 3.
The reactor f'eed pumps will be protected with a one-hour barrier.
b.
Cable Spreading Room One-hour barrier around affected control cables for the reactor feed pumps and power cables to MCC 98.
c.
Control Room One-hour barrier around affected control cables for the reactor feed pumps and power cables to MCC 98.
We have' not performed the fire protection review as a part of this re-p o.rt. This review is a necessary adjunct to the safe shutdown review and will be done by the'.NRC staff.
2.1.3 Alternative or Dedicated Systems Proposed Alternative shutdown will be provided to take the place of shutdown sys-tems in the switchgear room, control room and cable spreading room.
This will be achieved by a new RCIC control panel with a new' D.C. power supply and by modifications to the RCIC governor to allow control from the new RCIC panel and isolation of governor from the switchgear room, control room, and cable spreading room.
In addition, a new I).C. power supply will be provided for the emergency diesel generator and 4160 volt and 480 volt buses.
2.2 Section III L - Alternative and Dedicated Safe Shutdown Capability -Compliance 2.2.1 Per'formance Goals 2.2.1.1 For reactivity the CR0 system will be used; in the event of a fire the reactor will be scrammed from the control room. The~ reactor coolant makeup will b'e provided by the RCIC system.
This performance goal will be met by the in.stallation of a new RCIC control panel with its own D.C. power supply.
The licensee supplied an outline of these plans in their figures 1 thru 9.
There will also be a new RCIC governor control system. For the decay heat removal objective, the RCIC system, the safety relief valves and the RHR systems will be used.
Suppression pool cooling will be done by the RHR system and the service water systems.
It is our opinion that the above performance goals for post fire shutdown are acceptable.
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2.2.1.2 For process monitoring the licensee originally proposed instrumentation for reactor water level and pressure, supression pool tem'-
perature and level.
This is acceptable.
2.2.1.3 The licensee has stated that the supporting functions for cool-ing and lubrication will be available for the equipment used for safe shutdown functions.
J 2.2.2 Procedures, Manpower and Loss of Off-Site P'ower 2.2.2.1 The licensee has stated that the procedures for post fire safe shutdown are not yet completed.
2.2.2.2 The licensee states that three people will be available to per-form shutdown operation.
The manpower statement did not say whether the three people were enough to do the job.
This item wil remain open because a more detailed evaluation should be made after the procedures are written and an-alyzed for manpower requirements.
2.2.2.3 In their.submittals, the licensee has assumed the loss of l
offsite power, but the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> requirement needs confirmation by the licensee.
2.2.3 Repairs The licensee plans to do no repairs, therefore, no procedures are called for and no repair material has to be available on site.
2.2.4 Associated Circuits and Isolation-The isolation of the 125 volt D.C power supplies is by a transfer switch located in the RCIC room.
During our conference call of 11/ 20/81 it was verified that this device is manual and will be NEMA rated for the amper-age and voltage of the circuits involved.
For the other isolation devices, the licensee says only that " isolation devices" shall be used.
Before we can evaluate them, we will need to know what type they are for instrumentation, control, and power circuits. Associated circuits cannot be evaluated because they have not been given.
Instead, the licensee stated that their design philosophy will use an alternative shutdown system that will be isolated and separated from all cables "within the fire areas." This could result in an k
acceptable alternative sh'utdown method if the licensee provides adequate isolation (as noted above) and can provide separation information that i's ac-ceptable to the NRC staff.
Electrical schematics have not as yet been provided.
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2.2.5 High-Low Pressure Interface-The pressure interface was identified as two valves in the RHR system and two valves for the reactor heat vents. The licensee did not respond to the request to list the cables involved and to identify cables separated by less than a wall having a three hour barrier.
Instead, he stated that isola-tion will be " evaluated and provided as necessary."
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3.0 CONCLUSION
S AND RECOMMENDATIONS 3.1 Comoliance The licensee has taken measPres to address the post fire alternative shutdown capability and the proposed modifications will improve the existing system.
Aside from the open items listed below, the proposed modifications should meet the requirements of Section L of Appendix R from a design concept review.
Seismic evaluation of isolat;on devices could be required when detailed designs of all isolation device 3 have been made.
No attempt has been made to make this evaluation 'at this time since we are reviewing design concepts.only.
3.2 Recomm ndations 3.2.1 Open Item The basic design concept for the proposed new post fire shutdown system is acceptable.
3.2.2 Open Item New procedures for open items are not yet written.
When they have been completed, they should be reviewed by the NRC staff for manpower re-quirements and manual operations.
3.2.3 Open Item Based on the statement on the first page of Attachment I of their July 31, 1981 submittal, the licensee noted that there were three areas where the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> requirement could not be met prior to their efforts to provide alternative post fire shutdown.
It was assumed in this BNL review that. the licensee's position is that this* requirement can now be met in all areas of the plant since the three areas have been addressed in the submittal.
This should be confirmed by the licensee.
3.2.4 Open Item The licensee should submit information on the type of isolation proposed for the RCIC control and instrumentation circuits, the diesel generator 125 volt D.C. loads, the RHR loads, the service water load, and the UPS loads.
These should meet the requirements of Appendix R. Section L 7.
3.2.5 Onen Item Since the licensee has chosen not to identify and isolate associated circuits, he should demonstrate that the method chosen to avoid them can be used satisfactorily.
This includes showing tnat all parts of the alternative shutdown equipment meets the separation requirements of Section G of Appendix
.R and t' hat adequate isolation is used in accordance with Section L, Paragraph 7,
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3.2.6 Open Item For the high-low pressure interface the licensee should complete their analysis on this item and provide information on the isolation proposed.
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BROOKHAVEN NATIONAL LABORATORY MEMORANDUM DATE:
November 20, 1981 To:
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FROM :
E.A. MacDougall i
SUBJECT:
Telephone call of No.mber 20, 1981, Vermont Yankee referring to submittal of July 31, 1981 l
i Those people taking part in the conference call:
Vermont Yankee - R. Smith, L.u. Marsolais, and Jodka NRC - A. Singh BNL - E. MacDougall (1)
BNL Ouestion In Section 8a, response - cable spreading room Item 4 - the problem of
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hot shorts is addressed.
Did you also consider other electrical faults, namely grounding and open circuits?
Licensee Response Yes, we considered these types
- of electrical faults as well.
(2)
BNL Ouestion In Section,8c response you give three options to isolation control -
administrative measures, or key locking, or alarms in control room.
Our re-commendation has been to use only either of the last 2 options and not rely on administration controls.
Can you go along with this?
Licensee Response Yes l
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To:
File November 20, 1981 (3)
BNL Question In Section 8d response, what type of transfer and isolation switches are proposed?
Will they be NEMA rated for the loads involved?
Licensee Response L
These devices have not yet been selected.
The transfer switch shown in Figure 1 of subject submittal will be NEMA rated for the load and will be man-ually operated.
The isolation devices for instrunentation and control cir-cuits will be selected at a later date.
(4)
BNL Ouestion We need clarification to the response of Section 8e.
Licensee Response The licensee described their basic design philosophy in more detail' (5)
BNL Ouestion Does your response to question 8h on manpower apply to hot and cold,
shutdown or just hot shutdown?
Do you think that. three men can do the job.
Licensee Response Hot shutdown only; three men will be able to do the job satisfactorily.
(6)
BNL Question
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Regarding Attachment II lb response - can all cables normally used for shutdown be lost in the three concerned areas and alternative shutdown achieved at the RCIC control center and local control centers?
Licensee Response I
Only one ' fire at any given time was considered.
The control room and cable spreading room fires were considered to do the same damage.
The switch-gear room fire presented problems that resulted in the one hour fire barrier in the switchgear room shown in Figure 9.
All of the cables can be lost in a given fire in any one of the three areas and alternative post-fire shutdown can still be achieved.
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File November 20, 1981 (7)
SNL Question Regarding Attachment II le response - will schematics for new electrical work be provided?
Licensee Response A discussion followed where it was determined that a visit to the plant in 'the future would provide an opportunity to review the schematics, the other prints involved and resolve other technical questions.
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