ML20236Y500
| ML20236Y500 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 11/20/1987 |
| From: | Johnson I COMMONWEALTH EDISON CO. |
| To: | Murley T Office of Nuclear Reactor Regulation |
| References | |
| 3870K, NUDOCS 8712140039 | |
| Download: ML20236Y500 (8) | |
Text
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[N Comm:n=dth Edison
[O ) One First National Plaza. Chicago, Illinois C
'p(_,
7 Address Reply to: Post OfEeloi 7BF -
Chicago, !llinois 60690 - 0767 g
4 Novernher 20, 1987 l
Mr. Thomas E. Murley, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
Quad cities Station Units 1 and 2 Appendix R Exemption Request Submittals NRC Docke_t Nos. 50-254 and 50-265 Reference (a): Letter from I.M. Johnson to T.E, Murley dated September 30, 1987.
Dear Mr. Murley:
In the above referenced letter Commonwealth Edison requested an exemption request, 10.0, " Hot Shutdown Repairs (Fuse Replacements)". This exemption requested that fuse replacement be allowed in order to preclude spurious operations for the RCIC inboard steam supply isolation valve, In our review for Appendix R compliance, in anticipation of the upcoming Quad Cities Appendix R inspection, it has been determined that this hot shutdown repair is no longer required as a result of a non-Appendix R related modification which will be completed during the ongoing Quad Cities Unit 1 outage. As a result, Commonwealth Edison wishes to withdraw that request and in its place, we are providing a revised exemption request that eliminates the exemption request for the RCIC valve. The other fuse replacement exemptions in section 10.0 are still valid.
1 I
An identical modification will be completed on Quad Cities Unit 2 during its next refueling outage (Spring of 1988). As a result, Commonwe,Ith Edison requests a schedular exemption to the requirements of 10 CFR 50.48 Jor completing this modification. The basis and justification for our request ic described in Attachment 2 to this letter. Commonwealth Edison has put into place an interim compensatory measure for the period of time until the modification has been completed. As such, we feel our requested schedular exemption complies with the criterion provided in 10 CFR 50.12(a)(21)(v) and therefore, we request your approval of it.
8712140039 871.20 PDR ADOCK 05000254 l
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'T.E. Murley
- 2'-
4 h'ovember 20, 1987 l
since the issuance of Appendix R, Commonwealth Edison has maintained an aggressive program to ensure that compliance with the applicable require-mer4ts is achieved in a thorough and complete manner. As additional guidance become available, we have tried to react promptly to re-evaluate our compliance and initiate additional modifications as necessary. These modifications are a result of such ongoing reviews and have been discuss;d with members of your staff in a November 17, 1987 conference call.
Please direct any questions you may have regarding this matter to this offico.
Very truly yours, O
N w.
l I. M. Joh e Nuclear LScensing Administrator l
l 1m Attachments (1): Revised App. R Exemption Request for Hot Shutdown Repairs (Puse Replacement)
(2): Quad Cities Station Units 1 and 2 Schedular Exemption Request cc:
T. Ross - NRR A. B. Davis - Region III Admin.
J. Holmes - Region III Quad Cities Resider
- Inspector 3870K
QUAD CITIES 182 O
s 10.0 APPENDIX R EXEMPTION REQUEST FOR ROT SHUTDOWN REPAIRS (Fuse Replacement)
Per the provision of 10 CFR 50.12, Commonwealth Edison Company (CECO) request
.j exemption from the requirement of Section III.G.1 of Appendix R that one train of systems needed for hot shutdown be free of fire damage, in so far as this is interpreted as disallowing the use of repairs to implement hot shutdow..
(SECY-83-269, Section 1.2.1).
CECO specifically requests that an exemption be granted:
~\\(
i 1.
To allow the pulling and replacement of fuses in lieu of redundant fusing.
Section Justification For O
10.1 Pulling and Replacement of Fuses in lieu of Redundant Fusing.
Justification for these exemption requests is provided in the following section.
O
~
10.0-1 l
QUAD CITIES 1&2 0
10.1 JUSTIFICATION FOR PULLING AND REPLACEMENT OF FUSES IN LIEU OF REDUNDANT FUSING, 10.1.1 Dic.cussion Each safe shutdow, equipment item for which local control is utilized was checked to determine whether a fault on the remote circuit (prior to isolation) can blow a fuse needed for local control.
Three items were found l
to be deficient in this regard (See Table 10.1-1).
In order to operate tnis equipment, fuse replacement could be necessary.
The three circuits for which fuse replacement will be the only available solution are the engino starting controlc for the Unit 1, Unit 2 and swing (1/2) diesel generators.
These fuses are located in the respective diesel generator rooms.
Replacement fuses and fuse pullers will be maintained under l
surveillance in the proximity of these controls and emergency lighting is Q
placed so at to allow fuse replacement during blackout conditions.
For a fire in Fire Areas TB-II, TB-III and SB-I, an operator will be present in the required diesel generator rooms to control the diesel generators and, if necessary replace fuses.
Of the three circuits identified for fuse replacement, at most, two can be l
af fected by a single fire.
For a fire in Fire Area TB-II, fuse replacement could be required to start the Unit I and swing diesel generators.
If the l
fire occurred in Fire Area SB-I, fuse replacement could be required to start the Unit I and Unit 2 diesel generators.
Because of the minimal nurricer of possible fuse replacements, sufficient time is available to replace these fuses.
The pulling and replacement of fuses is being considered in the manpower requirements for the safe shutdown procedures.
All of the proposed fuse replacements are in low-voltage circuits (120 Vac or 125 Vdc). The fuses are of the cartridge-type and can be removed or inserted Q
under load by means of a standard fuse puller.
All are in control circuits (not power circuits) and are rated 15 amperes or less.
Actual load currents 10.1-1
QUAD CITIES 1&2
]
are considerably less, therefore no personal safety equipment is needed.
The operators have been trained at pulling and replacing similar fuses for routine testing and maintenance cperations.
I The fuses are presently connected at the point where control power enters the equipment, prior to any connections to switches, relays, lights, etc.
The presence of a redundant fuse would leave certain terminals of the LOCAL
- REMOTE selector switch hot if only the original fuse is pulled; in LOCAL position, the entire circuit could be hot. We maintain that the small auantity of required fuse replacements, combined with the small likelihood of a serious 1
fire, does not warrant this personnel hazard.
I Fuse pulling and rep 7acement is considered a repair for the purpose of 1
Appendix R; therefore, an exemption to Appendix R is necessary for the use of this operation in lieu of providing redundant fusirg.
10.1.2 Conclusion J
Following is a summary of the justific.ition for pulling and replacing fuses in safe shutdown control circuits.
1.
Only two safe shutdown circuits, eaca protected by a single fuse combination, could be affected by circuit faults resulting from any single fire.
2.
Pulling and replacement of fuses is routine practice at Quad Cities Station and the station operators are familiar with this operation.
3.
Replacement fuses and fuse pullers will be maintained in the proximity of the fuse replacement locations and kept under periodic surveillance.
4.
The circuits that are involved in this procedure are low-voltage control j
circuits.
The fuses are rated at 15 amperes or less and are actually carrying currents that are considerably less.
O 5.
The fuses in the equipment of concern cen be eas41y loceted ena ren,eced.
10.1-2
'O TABLE 10.1-1
,, g j_IST Of CIRCIUTS THAT REQUIRE FUSE REPLACEMENT PER IEIN 85-09 CONCERNS Time of Use (Minutes After Scram)
A.
Unit 1 diesel generator local controls 25-30 l
(engine starting) 8.
Unit 2 diesel generator local controls 25-30 (engine starting)
C.
1/2 diesel generator local controls 25-30 (engine starting)
O O
10.1-3
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