ML20082P851
| ML20082P851 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 11/30/1983 |
| From: | Howe P CAROLINA POWER & LIGHT CO. |
| To: | Vassallo D Office of Nuclear Reactor Regulation |
| References | |
| LAP-83-551, NUDOCS 8312090209 | |
| Download: ML20082P851 (7) | |
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CD&L SERIAL: LAP-83-551 Carolina Power & Light Company NOV 3 01983 Director of Nuclear Reactor Regulation At tention:
Mr. D. B. Vassallo, Chief Ope sting Reactors Branch No. 2
' Division of Lice.using Iktited States Nuclear Regulatory Commission Washington, DC 20555 BRUNSWI(X STEAM ELECTRIC PLANT, UNIT NOS.1 AND 2 DOCKET NOS. 50-325 AND 50-324 LICENSE NOS. DPR-71 AND DPR-62 REQUEST FOR ADDITIONAL INFORMATION ELECTRICAL DISTRIBUTION SYSTEM VOLTAGES Ref:
Carolina Power & Light Company letter, S. R. Zimmerman, to Office of Nuclear Reactor Regulation, NRC, Adeouacy of Station Electric Distribution Systems Voltages, November 23, 1982.
Dear Mr. Vassallo:
l On October 17, 1983, Carolina Power & Light Company (CP&L) informed l
the NRC (CP&L letter LAP-83-454, P. W. Howe to D. B. Vassallo) that your l
request for. additional information, dated September 1,1983, would be responded to by November 30, 1983.
Enclosed are CP&L's responses to the questions asked concerning and 2 of the above referenced letter.
The answers to Enclosure 3 of the referenced letter will be provided by January 31, 1984.
l Should you have any questions concerning this letter, do not hesitate to contact a member of our licensing staff.
Yours very truly, 8312090209 831130 P. W. Howe PDR ADOCK 05000324 P
PDR Vice President Brunswick Nuclear Project i
PPC/cfr (8592PPC)
Enclosures
~ (NRC-BSEP) cc:
Mr. ~ D. O. Myers
[
Mr. J. P. O'Reilly (NRC-RII) l' Mr. M. Grotenhuis (NRC) i l
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411 Fayetteville Street
- P. O. Box 1551
- Raleigh, N. C. 27602 uw.
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4 Carolina Power & Light Company Answers to Request for Addition Information Concerning Electrical Distribution System Voltages e
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The follmaing items are to clarif3 the referenced letter, Enclosure 1.
Question 1 The BOP relays are not Class 1E, and sense the voltage on non-Class 1E buses. Only Items e, f, and g are Class 1E item d is on a BOP bus and is a voltage relay.
Response
All relays (Items a through d) are nonsafe:y-related relays and sense the voltage on BOP bue.
The other relays (Items e through g) located on E-bus are safety-related relays purchased in accordance with UE&C specification 9527-01-145-2.. The seismic testing defined within this specification was performed in accordance with IEEE-344.
Question 2 Describe how the overvoltage coil is used as an undervoltage coil' (Items a, b, and e).
Re sponse The relays used for Items a, b, and e are under/over voltage relays with one operating coil and double throw contacts.
The lef t-hand contacts close as the voltage increases to some predetermined value.
The right-hand contacts close when the voltage decreases to some lower value.
Between these two voltage values, both contacts are open.
Question 3 Justify a Class 1E function initiated f rom non-Class 1E relays.
- Response The undervoltage protection controls for safety-related systems are designed to be controlled primarily by the signals from a relay located on the E-bus.
In addition, back-up control signals sensed by BOP buses are also provided to increase the reliability of the control function as summarized under this section.
NOTES:
1.
- denotes primary signal.
- denotes back-up signal.
2.
Permissives not performed by undervoltage relays are not shown (i.e., valve limit switches, etc. ).
a.
Diesel Generator Breaker
. Diesel generator breaker closes when:
+
e -
- (2) Loss of E-bus power sensed by 27/59E and all incoming and tie breakers are open.
b.
E-Bus Tie Breaker E-bus tie breaker trips if:
- (1) Loss of an associated E-bus power sensed by 27/59E OR
- (2) Loss of emergency power on the other E-bus which is tied with the associated E-bus.
c.
E-Bus Inc. Feeder Breaker (Slave)
Slave breaker trips if:
- (1) Degraded voltage on E-bus is sensed by two-out-of-three logic of 27DV relays.
(2) Master breaker trips.
d.
Safety-Related Load Shedding All f eeder breakers except for unit substation loads will be tripped when:
- (1) Loss of E-bus power sensed by 27/59E AND (2) The associated DG breaker is open.
e.
NSW Pump The following conditions permit sequential loading of the safety-related NSW pump:
- (1) E-bus power sensed by 27-1 and 27-2 is available (2) LOCA signal exists AND
- (3) DG feeder breaker closed or E-bus power sensed by 27-59E is available. <
f.
RHR & RCS Pumps Sequential Loads The following conditions permit sequential loading of the safety-related RRR & RCS pumps:
- (1) E-bus power sensed by 27-1 is available AND (2) LOCA signal occurs AND
- (3) Loss of B0P-bus power sensed by 27-1 AND
- (4) DG feeder breaker closed or E-bus power sensed by 27/59E is available.
Bypassing Sequential Loads RHR and RCS loads bypass when:
- (1) E-bus power sensed by 27-1 or 27-2 is available AND/OR
- (2) BOP-bus power sensed by 27-1 is available.
g.
Diesel Generator l
l Diesel generator starts when:
L
- (1) Loss of emergency power sensed by 27HS i
- (2) Loss of power on BOP-bus sensed by 27HS, 27/59U, or 27/59S.
To reiterate, all required safety-related functions are performed by l
qualified undervoltage relays located on the E-bus.
The BOP-bus relays ere utilized to enhance the primary control functions such as for Item f l
and g above.
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The following items are to clarify the referenced letter, Enclosure 2:
Question 4 In Section 2.1, what are the equipment ratings?
Are they within the analyzed voltages?
If outside, assess equipment operation / damage.
Re sponse The nominal voltage ratings of the devices are 115 V as specified under Section 5.0 of the " Voltage Drop Study for 208/120 Volt Safety-Related Loads," Revision 2, previously forwarded to the NRC.
The recommended operating voltage ranges for relay coils and solenoids are 90%-110% of 115 V (nominal voltage).
The summary of the load study shows that all instrumentation devices will be over 90% of the rated voltage at twice LOCA conditions.
(Refer to the table for worst case terminal voltage.)
The maximum overvoltage case could occur at device terminals when a unit is shutdown, resulting in overheating of coils. This overheating could affect the life span of the continuously energized coils. This is not seen as a significant problem and is supported by operating experience.
Furthermore, the actual overvoltage value will be mitigated since this study was based on switchyard voltage of 100%, which is expected to drop to 96% at off peak and 98% at peak.
Worst Case Terminal Voltage Base Actual Voltage Terminal Unit Panel Voltage Voltage Drop Voltage Condition E7 32AB 208 185 0.6 106.2 (92.3%)
2 x (LOCA)
E7 2C 208 185 0.06 132.2 (115%)
SAT Light Load j'
E8 2B 208 185 3.0 103.8 (90.3%)
2 x (LOCA)
- E8 2D 208 185 0.05 132.16 (114.6%) SAT Light Load NOTES:
.1.
Actual panel voltage is line-to-line voltage in 3 phase /
4 wire system.
2.
Terminal voltage is phase-to-ground voltage.
I terminal vtg = (actual line vtg/ / 3 ) = vtg drop I
[-
Question 5 Clarify Section 2.3:
Have the recommended tap settings been implemented?
! f I
w Re sponse The suggested tap changes haves been made as per PM-80-246, 247, 257, and 258.
(8592PPC cfr)