ML20059A802
| ML20059A802 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 08/14/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20059A794 | List: |
| References | |
| NUDOCS 9008230227 | |
| Download: ML20059A802 (4) | |
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SUPPLEMENTAL SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION NEW SWITCHGEAR FOR 10 CFR 50, APPENDIX R CONCERNS FACILITY OPERATING LICENSE NO. OPR-61 CONNECTICUT YANKEE ATOMIC POWER COMPANY HADDAM NECK PLANT DOCKET NO. 50-213 INTRODUCTION:
By letter dated June 11, 1990, Connecticut Yankee Atomic Power Company (the licensee /CYAPCO) responded to the staff's January 22, 1990 Safety Evaluation (SE) on the subject matter.
CYAPCO's letter provided clarification to certain statements in the staff's SE and provided additional information on changes that have occurred.since t'* staff's initial review.
EVALUATION:
-The following clarifications presented by the licensee are cons stent with the staff's understanding of the licensee's initial submittal.
The clarifications are listed for completeness and accuracy and do not affect the,.onclusions L
reached in the SE.
A1.
The new switchgear project provides a means for isolating electrical power sources and centrol in event
.of fires for the containment cable vault as well as the other areas noted in the SE.
- A2.
Handholes and cable chases utilize Siltemp wrap, which is nnt a rated fire barrier, to achieve separation requi re';.ents.
Rated fire wrap is used only in the E
cable Liault and RHR B pit to address-Appendix R' separation criteria.
A3.
1 trder to power selected loads from the new sotchgear room, existing cables that are no longer required after the loads are transferred will be disconnected and will either be removed or decommissioned in place.
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it A4.
Only a minor' subset of new t; ables will be installed in i
existing cable trays.
AS. - Control power for the new 4160V breaker will be supplied from the 125V de feeder which supplies the other 4160V breakees.
The de feeder taps off the new 125V de bus B (formerly named Bus 2A)
Retaote control and annunciation of the 4160V breaker will be provided by cables to the main control room.
The existing Appendix R knife switch KS panel located in the diesel generator room 2B will provide the means for isolating these cables from the control room.
A6.
The breakers on each end of the new circuit being added from Bus 11 in the new switchgear room to Bus 6 in the existing switchgear room will normally be open and j
controlled locally by administrative procedure.
The i
breakers would only ba closed for a backup source when the normal 4160/480V supply breaker is open.
A7.
Motor operated valve BA-MOV-32 is powered from MCC-5
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and is automatically aligned to either Division A or B.
AB.
The_nex Battery charger BC-1B is adequate to supply the normal vorst-case loads and to restore the battery to full charre within a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period.
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A9.
Vital Panel C1 feeds Division B-related Appendix R instrumentation at the new remote instrumentation panel in the new s.itchgear building, and Vital. Panels C1 and D1 feed Vital r6aels C and D in the main control room.-
l A10. Normally locked-open ties from Bus.C to Class 1E Buses A and BX will be locally operated using keys and administrative controls such that only one bus can be crosstied at a time.
Some bas names have been changed, some loads have been transferred from one bus j'
to another, and some loads have been added since our initial review, as follows:
Bl.
Since issuence of the SE, 125V de Bus 1 has been renamed Rus A, the new 125V de Bus 2A renamed Bus B, 125V de Bus 2 renamed as Bus BX and 125V de Bus 3 renamed as Bus C.
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B2.
Power distribution Panel LP-U7-1 will be powered from:
480V Bus 11 rather than from 480V MCC Bus 12-11.
83.
A new MCC 12 and an' alternate feed to CAR Fans 3 and 4, in addition to the other loads listed in the SE, will be powered from Bus 11.
.i B4.
The new non-Class IE 480V distribution panel powered by Bt.s 11 will supply heating, ventilation and air condtioning to th:, third floor in the new switchgear i
building as well as to the other floors.
1 B5.
The 120/208V distribution panel powered by MCC 12-11 feeds the plant paging system, as well as the other 3
loads listed in the SE, in the new switchgear building.
B6.
The emergency turbine oil pump P-81-1A and the 1
emergency air side hydrogen seal oil pump P-80-1A are powered from 125V de Bus C rather than Bus B.
B7.
In addition to those loads listed in the SE, loads SW-H0V-837A, CH-H0V-257B and F-89-1A will be powered from 480V MCC 12-11; loads F-89-1B and SW-M0V-8378 will be powered from 480V MCC 13; and feed to the space heaters.
for the 4160/480V Load Center Transformer will be from the 120/208V distribution panel PP-U8-1.
During a telecon on July 17, 1990, the licensee stated that the above-load changes-and additions have been analyzed by CYAPC0 to assure that the changes do not a
result in any equipment overloadings or excessive voltage drops, and d qu-mentation of these analyses will be maintained and made available for NRC audit should such audit _be desired.
We find this to be acceptable.
The licensee noted other changes and clarifications to the SE as follows:
C1. Our SE stated that the Division B 125V de bus would essentially be extended into the new switchgear room by 4
a tie from the existing Division B 125V de bus.
The licensee notes that Division B is a,ew division in the l
new switchgear building, complete with a new battery, and that the new Division B 125V de is extended to Bus BX in the existing switchgear room.
The licensee also notes the B battery is a new battery, not an existing one.
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c C2. The new 4160/480V circuit connects new Class IE loads of approximately 133 kVA (rather than 244 kVA) to the L
diesel generator.
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C3. The SE stated that the'new 4160/480VtietoBusil-and i
the cross tie from Bus 6 should not be closed simultaneously because the available fault current at Bus 6 could exceed the Bus 6 breaker ratings. This is no longer a problem because the cable-tie Ength is L
sufficient to limit the fault current.
However, the p
two ties must not be closed simultaneously (i.e., both 1
feeds) since overtripping could occur in event of a fault. -During a telecon on July 17, 1990, the licensee 1
L stated that the lack of coordination would only occur
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between the bus tie breakers and the breakers on the load side of Bus 6.-
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The abo o,= ems are noted primarily for completeness and accuracy.
Item C3 does not t rat safety of the plant because the 480V cross tie is normally open and J
L administrative 1y controlled.. Items C1 and C2 changes are in a positive direction toward increased safety, i
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SUPPARY AND CONCLUSION:
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a By letter dated' June 11', 1990, the licensee for :he Haddam Neck Plant responded L.
to the NRC staff's January 22, 1990 SE pertaining to the new switchgear and u
related changes at the plant for fire protection. Certain. clarifications to the L
staff's SE.and changes that have occurred since issuance of the SE were noted.
L Our. review of this latest submittal has disclosed only one-item that could have I
some safety significance.1The addition of loads and shifting of loads from one K
bus to another could affect system voltage levels and loadings on transformers,
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cables, etc.
However, the licensee has checked and confirmed that the load 1
changes do not result in unacceptable voltage drops or overloadings.
-Principal Contributor:
A. Toalston Dated:
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