ML17261A319
| ML17261A319 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 10/09/1981 |
| From: | Maier J ROCHESTER GAS & ELECTRIC CORP. |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML17261A320 | List: |
| References | |
| TASK-06-07.B, TASK-06-07.C, TASK-06-10, TASK-07-03, TASK-08-02, TASK-08-03, TASK-6-10, TASK-6-7.B, TASK-6-7.C, TASK-7-3, TASK-8-2, TASK-8-3, TASK-RR NUDOCS 8110140360 | |
| Download: ML17261A319 (12) | |
Text
RPCHESTER GAS kgb ELECTRICCOPF'ORkTIPh2
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89 EAST kVEIIU"",ROCHESTER, Y.Y, I '6~9 W<CSl"aW (oNChg i~ticzar -Pc. 5-6 2~0 October 9, 1981 I
Director of Nuclear Reactor Regulation Attention:
Yr. Dennis I!. Crutchfield, Chief Operating Reactors Branch No.
5 U.S. Nuclear Regulatory Commission Washington, D.C.
20555
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Subject:
SEP Topics VI-7.B, VI-7.C, VI-10, VII-3, VIII-2, VIII-3 R.
E. Ginna Nuclear Power Plant Docket No.
5 0-244 e<< ~<<~
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Dear Nr. Crutchfield:
This letter is in response to your letter of September 16, 1980 to Leon D.
$fhite, Jr. concerning a request for additional information relative to the inverters used at, the Ginna Station.
The response to the specific questions, as well as required
- drawings, are attached.
Very truly yours, A~
Jo n E. llaier Attachments
3.
Describe the consequence of one or more load groups on a single dc source losing power (e.g.
automatic initiation of
- mode, loss of indication in the control room, loss of annunciators, loss of plant communications, loss of emergency telephones).
Response
Because of the Ginna design, shown in RGS E drawing N21489-269, Rev.
0, with the use of static switches and constant voltage transformers, the loss of a dc source or inverter would not result in the loss of any instru-ment buses; their loss would result in a fast (bumpless) transfer to the Class IE CVT dedicated to that channel.
The normal dc supply for the main control board annun-ciators is from battery 1A.
The loss of a dc source (from the 1A battery) automatically results in a transfer to the 1B battery.
This transfer scheme is described in SEP Topic VI-7.C.1, transmitted by letter from John E. h1aier to Dennis M. Crutchfield, dated July 14, 1981.
The loss of a dc source would not result in the auto-matic initiation of the ECCS.
Containment Isolation and Containment Ventilation Isolation by fail-closed air-operated valves would occur; these could not be reset until dc power is restored.
Reactor trip could occur.
The loss of a dc source would not affect plant communi-cation with the public address system or emergency telephones, since these have no'rmal ac power, with separate dc power as a backup.
The loss of a dc source would result in a loss of status indication for components on the affected load group; however, all required safe shutdown and accident mitigation functions have redundancy; therefore, loss of safety function would not occur.
Attachment:
Responses to NRC Questions in 9/16/80 letter on inverters (Topics VI-7.B, VZ-7. C, VZ-10,.
VZI 3g VIII 2g VIII 3) 1.
Quantify the number of instrument inverters in your plant and for each inverter:
a) b)
Response
identify the inverter and its power supplies; and describe the switching features that are provided to switch inverter power supplies and inverter loads (including synchronization circuits).
RGB E drawing N21489'-269, Rev.
0 shows the arrangement of the two vital inverters, 1A and 1B, and the respective 125 VDC sources, batteries 1A and 1B.
Each inverter is backed by a constant voltage transformer (CVT) synchro-nized with the inverter, and is fed from a Class 1E motor control center receiving power from the same source as the associated battery charger.
This synchronization circuit is shown on Solidstate Controls Inc.
(SCZ) Drawing 4014D14256 Rev. 1.
A static switch responds to a loss of inverter output by transferring the vital instrument bus from the inverter to the CVT.
This is accomplished by electroni-cally changing the gating of the SCR's shown in SCI Drawing ()015C14255, Rev.
0 to allow current flow from the alternate source input when the output voltage falls below the setpoint.
Zt should be noted that the automatic transfer to the CVT does not parallel redundant channels or trains.
It does,
- however, provide continuous power to the vital AC panel.
2.
Provide the requirements for:
a) testing the transfer paths described in your responses to 1 above, and b) limiting the number of redundant load groups that may be placed on any maintenance power source during each operating condition.
Response
The transfer paths are tested subsequent to component maintenance and testing, on an annual refueling outage schedule.
Testing requirements are specified in the Ginna Station maintenance procedures Y38.2 and M38.3.
As shown in RG&E Drawing N21489-269, the instrument bus feeder breakers are mechanically interlocked to prevent paralleling the maintenance power supply and the normal feeder from the inverter.
Maintenance procedures Y38.2 and N38.3 restrict the placing of more than one instru-ment bus on the maintenance power source during testing.
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89 EAST AVENUE, ROCHESTER, N.Y. 14649 JOHN E.
MA I ER VICE PRESIDENT TCLCPHONC ARCA COOC 7I6 546-2700 October 9, 1981 C>14 g@
Director of Nuclear Reactor Regulation Attention:
Mr. Dennis M. Crutchfield, Chief Operating Reactors Branch No.
5 U.S. Nuclear Regulatory Commission Washington, D.C.
20555
Subject:
SEP Topics VI-7.B, VI-7.C, VI-10, VII-3, VIII-2, VIII-3 R.
E. Ginna Nuclear Power Plant Docket No. 50-244
Dear Mr. Crutchfield:
This letter is in response to your letter of September 16, 1980 to Leon D. White, Jr. concerning a request for additional information relative to the inverters used at the Ginna Station.
The response to the specific questions, as well as required
- drawings, are attached.
Very truly yours, A ~~
Jo n E. Maier Attachments
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3.
Describe the consequence of one or more load groups on a single dc source losing power (e.g.
automatic initiation of ECCS, automatic initiation of transfer from ECCS injection made to recirculation
- mode, loss of indication in the control room, loss of annunciators, loss of plant communications, loss of emergency telephones).
Response
Because of the Ginna design, shown in RG&E drawing N21489-269, Rev.
0, with the use of static switches and constant voltage transformers, the loss of a dc source or inverter would not result in the loss of any instru-ment buses; their loss would result in a fast (bumpless) transfer to the Class IE CVT dedicated to that, channel.
The normal dc supply for the main control board annun-ciators is from battery 1A.
The loss of a dc source (from the 1A battery) automatically results in a transfer to the 1B battery.
This transfer scheme is described in SEP Topic VI-7.C.1, transmitted by letter from John E. Naier to Dennis M. Crutchfield, dated July 14, 1981.
The loss of a dc source would not result in the auto-matic initiation of the ECCS.
Containment Isolation and Containment Ventilation Isolation by fail-closed air-operated valves would occur; these could not be reset until dc power is restored.
Reactor trip could occur.
The loss of a dc source would not affect plant communi-cation with the public address system or emergency telephones, since these have normal ac power, with separate dc power as a backup.
The loss of a dc source would result in a loss of status indication for components on the affected load group; however, 'all required safe shutdown and accident mitigation functions have redundancy therefore, loss of safety function would not occur.
r4 P
Attachment:
Responses to NRC Questions in 9/16/80 letter on inverters (Topics VI-7.B, VI-7.C, VI-10, VII 3g VIII 2~ VIII 3) 1.
Quantify the number of instrument inverters in your plant and for each inverter:
a) identify the inverter and its power supplies; and b) describe the switching features that are provided to switch inverter power supplies and inverter loads (including synchronization circuits).
Response
RGE E drawing 521489-269, Rev.
0 shows the arrangement, of the two vital inverters, 1A and 1B, and the respective 125 VDC sources, batteries 1A and 1B.
Each inverter is backed by a constant voltage transformer (CVT) synchro-nized with the inverter, and is fed from a Class 1E motor control center receiving power from the same source as the associated battery charger.
This synchronization circuit is shown on Solidstate Controls Inc.
(SCI) Drawing 5014D14256 Rev. 1.
A static switch responds to a loss of inverter output by transferring the vital instrument bus from the inverter to the CVT.
This is accomplished by electroni-cally changing the gating of the SCR's shown in SCI Drawing 0015C14255, Rev.
0 to allow current flow from the alternate source input when the output voltage falls below the setpoint.
It should be noted that the automatic transfer to the CVT does not parallel redundant channels or trains.
It does,
- however, provide continuous power to the vital AC panel.
2.
Provide the requirements for:
a) testing the transfer paths described in your responses to 1 above, and b) limiting the number of redundant load groups that may be placed on any maintenance power source during each operating condition.
Response
The transfer paths are tested subsequent to component maintenance and testing, on an annual refueling outage schedule.
Testing requirements are specified in the Ginna Station maintenance procedures M38.2 and M38.3.
As shown in RGGE Drawing 521489-269, the instrument bus feeder breakers are mechanically interlocked to prevent paralleling the maintenance power supply and the normal feeder from the inverter.
Maintenance procedures M38.2 and M38.3 restrict-the placing of more than one instru-ment bus on the maintenance power source during testing.
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