ML19330A901
| ML19330A901 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 07/24/1980 |
| From: | Utley E CAROLINA POWER & LIGHT CO. |
| To: | Ippolito T Office of Nuclear Reactor Regulation |
| References | |
| NO-80-1093, NUDOCS 8007290723 | |
| Download: ML19330A901 (7) | |
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July 24, 1980 File: NG-3514 (B)
Serial No. : NO-80-1093 Office of Nuclear Reactor Regulation ATTENTION:
Mr. T. A. Ippolito, Chief Operating Reactors Branch No. 3 United States Nuclear Regulatory Commission Washington, D. C.
20595 BRUNSWICK 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 ADEQUACY 0F STATION ELECTRICAL DISTRIBUTION SYSTEMS VOLTAGE
Dear Mr. Ippolito:
This is in response to your May 16, 1980 letter which requested additienal information regarding the adequacy of station electrical distribution systems voltage for the Brunswick Steam Electric Plant, Unit Nos. 1 and 2.
This request is a follow-up to our October 8, 1979 submittal.
Carolina Power & Light Company's responses to your requests are attached. Certain information which you have requested is incomplete at this time. This information will be provided in accordance with the dates stated in the attachment. We trust that this information will be satisfactory for your use.
Yours very truly,
.. f [ M A n E. E. Utley Executive Vice President Power Supply and Engineering & Construction JAM /dk Attachments
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I 8007200 N /
b BRUNSWICK UNIT NOS. 1 AND 2 ADDITIONAL INFORMATION ADEQUACY OF STATION ELECTRICAL DISTRIBUTION SYSTEMS VOLTAGE
Reference:
NRC letter dated May 16, 1980 NRC Request 1.
Your letter dated October 25, 1976 calls for the switchyard voltage to be maintained between 98% and 102%, and your letter of October 8,1979 gives the switchyard operating voltage range as 94.5% to 101% and states that the voltage had not fallen below 98%.
In your study you have used taps to keep the voltage at 230 KV and have used grid voltages of 95% and 105%
for analysis. However, we want to find out the minimum and maximum grid voltages according to guideline number six.
CP&L Response 1.
A new study by our System Operations De par tment is based on our present schedule of maintaining switchyard voltage during on peak periods at 102%
(234.6 KV) and during off peak periods at 100% (230 KV).
During a trip of both units from full power, with a simultaneous starting of all emergency core cooling equipment, the switchyard voltage is only expected to drop 4% from the pre-trip voltage levels to 98% (225.4 KV) on peak and to 96% (220.8 KV) off peak.
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G BRUNSWICK UNIT NOS. 1 AND 2 NRC Request 2.
The NRC guidelines for voltage drop calculations, in general, request that the minimum and maximum voltages be calculated and analyzed "at-the terminals of each safety load".
The analysis in your October 8, 1979 submittal does not include safety loads below the 480 volt level l
(instrumentation, controls, etc.). Please provide this analysis.
CP&L Response
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2.
Review of the safety related loads indicates that voltage studies must be performed for circuits on the following nine (9) 208/120 volt distribution. panels:
Panel No Node No.
Location 2A H$6 Control Building 2B H$/
Control Building 2C HY$
Control Building l
2D HY1 Control Building 32A HW8 Control Building 32B HW9 Control Building 32AB HXp Control Building 2A-DG HQ6 Diesel Generator Building 2B-DG HW7 Diesel Generator Building The results of the required analyses will be provided to the NRC by October, 24, 1980.
O r
s BRUNSWICK UNIT NOS. 1 AND 2 NRC Request 3.
The one-line electrical diagram from the Brunswick FSAR (8.10-1) shows 4160 an/ 30 volt tie breakers between Unit 1 and Unit 2; therefore; it would. possible to supply all normal operating and shutdown loads to both pisats from one SAT. In order to conform to the NRC guidelines for voltage drop calculations, item 2, this possibility should be considered in your analysis, and it appears that it was not. Please provide analysis of one SAT supplying all loads to both plants.
CP&L Response 3.
Since the issuance of FSAR Fig. No. 8.10-1 several changes in operating philosophy have taken place and breaker control logic implemented to restrict the use of ties between Unit No.1 and Unit No. 2.
The 4160 volt tie breakers between emergency buses El (AGl) and a.
E2 (AH8) and emergency buses E3 (AJ6) and E4 (AL4) have been disconnected and racked out.
b.
Although the 4160 volt tie breakers between emergency buses El (AG9) and E3 (AJ5) and emergency buses E2 (AH9) and E4 (AL5) are normally open, an accident signal will cause a trip should they be closed and a reclosure is not permitted for ten minutes, The tie breaker between buses 1B and 2B (LAB 4) can only be closed c.
when the start-up transformer incoming line breakers to Bus 1B (IAB2)
. and Bus 2B (2AB2) are open and the disconnect links (lA91 or 2A91) to cne start-up transformer are removed.
d.
The tie breakenrbetween Buses Common A and Common B (2AAl) can only be closed when one of the incoming line breakers (lAA2 or 2AA2) are open. As this tie breaker is used during certain normal operating
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lineups, additional voltage studies are being perforred which will include the maximum load of 3MVA supplied through this tie breaker.
The results of this analysis will be provided by September 26, 1980.
BRUNSWICK UNIT NOS. 1 AND 2 NRC Request 4.
-The NRC guidelines for voltage drop calculations, item 8, states that "The analysis should document the voltage setpoint and any inherent or adjustable (with nominal setting) time delay for relays which initiate or execute (1) automatic transfer of loads from one source to another; (2) automatic load shedding; or (3) automatic load sequencing." Please provide these settings.
CP&L Response 4.
The voltage relays requested are as follows:
s Relay Catalog No.
Setting Function a.
27/59S 121AV53K1A 105V/83V a.
Load sheds all breakers (B0P - Bus)
(5.5 see when on its associated bus voltage drops to zero) b.
Trips its associated Feeder to Emergency Bus c.
Starts Diesel Generators b.
27/59U 12LAV53K1A 105V/83V a.
Load sheds all breakers (BOP - Bus)
(5.5 see when on its associated bus 4
4 voltage drops to zero) b.
Trips its associated Feeder to Emergency Bus e
c.
Starts Diesel Generators c.
27-1 12HFA65D69H Instantaneous a.
(BOP - Bus)
Permits sequential loading of RHR and Core Spray Pumps during DBA b.
Permits bypass of sequential loading circuits if off-site power is available c.
Permits operation of Conventional Service Water Pumps if off-site power is available
BRUNSWICK UNIT NOS. 1 AND 2 Relay Catalog No.
Setting Function d.
27/59E 12IAV53KlA 105V/98V a.
Permits closure of diesel (E-Bus)
(5 secs @
generator breaker 70% V.
1.5 secs @
b.
Load sheds all breakers on 0% V.)
its associated bus c.
Trips tie breakers e.
59D 121AV51A1A 55V/1L a.
Permits closure of diesel (E-Bus)
(.25 see @
generator breaker 100% V.)
f.
27-1 12HFA65D69H Instantaneous a.
Starts sequential loading 27-2 12HFA65D69H Instantaneous b.
Permits bypass of sequential (E-Bus) loading circuits if off-site power is available g.
27HS 12HGA17C63 Instantaneous a.
Starts its associated diesel (E-Bus) generator h.
27 DV ITE - 27D 106.5V/10 see a.
Isolates its associated (E-Bus) emergency bus from off-site distribution system when voltage is below 89.5%
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BRUNSWICK UNIT NOS. 1 AND 2 NRC Request 5.
In order to validate your analysis, the voltages obtained in your onsite test should be compared directly with your analysis. Do you intend to do this?
CP&L Response CP&L's original response of October 8,1979 committed to perform an onsite test where one unit would be tripped from approximately 25%
power while simultaneously starting all emergency core cooling equipment.
However, Mr. Don Weber, NRC consultant, called on June 4,1980 to discuss the on-site test and stated that the planned test was much more than he would require. At this time Mr. Weber asked the plant to only conduct one of the voltage transients listed in the Appendix to the Voltage Drop Study (transmitted by our October 8, 1979 letter) such as the one listed on page A10, Starting Screen Wash Pump 23, and compare these results with the analytical report. At this time Brunswick is preparing to run an on-site test as Mr. Weber suggested. The on-site test data will be compared to the analytical study and the results will be submitted one month after the test is sucessfully run.
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