ML18057B334
| ML18057B334 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 10/22/1991 |
| From: | Slade G CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-91-06, GL-91-6, NUDOCS 9110300218 | |
| Download: ML18057B334 (10) | |
Text
~~trn~llrnm~rn
!)!l[i]W~f l'DWERINli
- MICHlliAN'S l'RDliRESS Palisades Nuclear Plant:
27780 Blue Star Memorial Highway, Covert, Ml 49043 October 22, 1991 Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT -
GB Slade General Manager RESPONSE TO GENERIC LETTER 91-06, "ADEQUACY OF SAFETY RELATED DC POWER SUPPLIES," PURSUANT TO 10 CFR 50.54(f) (GENERIC LETTER 91-06)
This submittal provides our response to Generic Letter 91-06, dated April 29, 1991, made at the request of the Staff of the US Nuclear Regulatory Commission pursuant to Section 182 of the Atomic Energy Act of 1954, as amended and 10 CFR 50.54(f).
Generic Letter 91-06 requests information pertinent to the safety related de power supplies, which for Palisades, are the station batteries. At Palisades the station batteries are designed to furnish continuous power to certain normal plant control and instrumentation circuits and to control and instrumentation circuits associated with the engineered safeguards systems.
They are also used to supply emergency plant lighting.
Two identical batteries feeding separate de control centers are provided to assure reliability. The station batteries are described in detail in the Palisades Final Safety Analysis Report (FSAR), Section 8.4.2.
The attachment to this letter provides Palisades specific responses to the items requested in Enclosure 1 to Generic Letter 91-06
.----
Gerald B Slade General Manager Attachment CC:
Administrator, Region III, USNRC NRC Resident Inspector, Palisades
,,,,------ -9TJ~0:2;f(ii)2 f :=:--*=F1_1_ n--.-.-,----
P[rR A:C - -. -.
~ *
~
p
- 11-"-*K 0!'.50002!55 PDR A CllliS ENERGY COMPANY
~\\ \\ \\
CONSUMERS POWER COMPANY To the best of my knowledge, information and belief, the contents of this submittal are truthful and complete.
P Hoffman, Vic re Nuclear Operation
~
Sworn and subscribed to before me this.;2.:2..*h; day of 67~ 1991.
NOtarYUb1 i c Michigan My commission expires BEVERLY ANN AVERY NOTARY PUBLIC-JACKSON COUNTY, Ml MY COMMISSION EXPIRES 12-7-92
ATTACHMENT Consumers Power Company Palisades Plant Docket 50-255 Response to Generic Letter 91-06 October 22, 1991 7 Pages
Generic Letter 91-06 Item Numbers and Responses 1
Unit: Palisades 2.a "The number of independent redundant divisions of Class lE or safety-related de power is:"
2.b "The number of functional safety-related divisions of de power necessary to attain safe shutdown is:"
3 "Does the control room have the following separate, independently annunciated alarms and indications for each division of de power?"
3.a.1 "Alarms on battery disconnect or circuit breaker open:"
Separate undervoltage sensors 27/DlO and 27/D20 indicate in a common control room annunciator, EK-0548.
Sensors 27/DlO and 27/D20 have a setting between the nominal 125V de battery terminal voltage and the higher battery float voltage when connected to its charger.
3.a.2 "Alarms on battery charger disconnect or circuit breaker open (both input ac and output de):"
No The control room has a single annunciator, EK-0541, for both the AC input and the DC output for all four chargers. Disconnects or circuit breakers are not monitored.
Undervoltage of AC input is monitored which is essentially the same as the input breaker. Undervoltage of DC is monitored at the output of the charger but before the output breaker.
Annunciator EK-0548, "125V de Bus undervoltage/trouble", will alarm if battery voltage falls below normal charger output voltage.
3.a.3 "Alarms on de system ground:"
The control room has a single annunciator, EK-0547, for DC system ground for both DC buses.
Individual indicators but no alarms, are in the cable spreading room.
3.a.4 "Alarms on de bus undervoltage:"
No Separate undervoltage/loss of voltage sensors 27/DlO, 27/D20, 74/Dl, and 74/D2 indicate in a common control room annunciator, EK-0548.
Individual indicators are in the cable spreading room.
3.a.5 "Alarms on de bus over voltage:"
No Palisades does not have any DC bus over voltage alarm.
3.a.6 "Alarms on battery charger failure:"
The control room has a single annunciator, EK-0541, for both the AC input and the DC output for all four chargers.
Undervoltage of AC. input and undervoltage of DC are monitored. This combination of alarms essentially monitors for charger failure.
3.a.7 "Alarms on battery discharge:"
Palisades has no alarms on battery discharge.
The control room has a single annunciator, EK-0548, for 125V de undervoltage/trouble.
The undervoltage sensor settings tell when voltage is below charger output voltage, indicating a battery dtscharge.
3.b.1 "Indications of battery f7oat charge current:"
No Each DC bus has a float charge current indicator, but it is in the cable spreading room, not the control room.
3.b.2 "Indications of battery circuit output current:"
Each DC bus has a circuit input/output current indicator, but it is in the cable spreading room, not the control room.
3.b.3 "Indications of battery discharge:"
No There is no indicator for battery discharge other than the output current indicator.
3.b.4 "Indications of bus voltage:"
Each DC bus has a circuit voltage indicator, but it is in the cable spreading room, not the control room.
3.c "Does this unit have written procedures for response to the above alarms and indications?"
Yes Alarm Response Procedure (ARP) 3, "Electrical Auxiliaries and Diesel Generator Scheme EK-05 (EC-11)".
Off Normal Procedure (ONP) 2.3, "Loss of DC Power".
Emergency Operating Procedure (EOP) 3.0, "Electrical Emergency Recovery".
4 "Does this unit have indication of bypassed and inoperable status of circuit breakers or other devices that can be used to disconnect the battery and battery charger from its de bus and the battery charger from its ac power source during maintenance or testing?"
No Annunciator EK-0548 includes an alarm if the DC Bus Tie Breakers 72-10 or 72-20 are open.
Additional indications are those already discussed in question #3 above.
5 "If the answer to any part of question 3 or 4 is no, then provide information justifying the existing design features of the facility's safety-related de systems" For each question that was answered 'no', information has been provided with that question.
Furthermore, the current design has been reviewed and accepted by the NRC.
See references 1, 2 and 3.
6(1)
"Have you conducted a review of maintenance and testing activities to minimize the potential for human error causing more than one de division to be unavailable?"
Yes Such a review has been conducted on an ongoing basis.
As each maintenance and test procedure receives it's periodic review or is revised, changes are considered as appropriate.
6(2)
"Do plant procedures prohibit maintenance or testing on redundant de divisions at the same time?"
Yes Technical Specification 3.7.2; Standing Order #54, 3.7.2; System Operating Procedure (SOP) 30, paragraph 4.1.
7 "If the facility Technical Specifications have provisions equivalent to those found in the Westinghouse and Combustion Engineering Standard Technical Specifications for maintenance and surveillance, then question 7 may be skipped."
Palisades does not have equivalent Technical Specifications 7
"Are maintenance, survei77ance and test procedures regarding station batteries conducted routinely at this plant? Specifica77y:"
7.a "At least once per 7 days are the following verified to be within*
acceptable limits:"
7.a.l "Pilot cell electrolyte level?"
Done monthly per Technical Specification Surveillance Test ME-12, "Battery Checks".
7.a.2 "Specific gravity or charging current?"
Done monthly per Technical Specification Surveillance Test ME-12.
7.a.3 "Float voltage?"
No Done monthly per Technical Specification Surveillance Test ME-12.
7.a.4 "Total bus voltage on float charge?"
Done monthly per Technical Specification Surveillance Test ME-12.
7.a.5 "Physical condition of a77 ce77s?"
No Done monthly per Technical Specification Surveillance Test ME-12.
7.b "At least once per 92 days, or within 7 days after a battery discharge, overcharge, or if the pilot cell readings are outside the 7-day surveillance requirements are the following verified to be within acceptable limits:"
7.b.l "Electrolyte level of each cell?"
Yes Done monthly per Technical Specification Surveillance Test ME-12.
7.b.2 "The average specific gravity of a77 ce1ls?
11 No Data taken quarterly per Technical Specification Surveillance Test ME-12, but not averaged.
7.b.3 "The specific gravity of each ce77?
11 Yes Quarterly per Technical Specification Surveillance Test ME-12.
7.b.4 "The average electrolyte temperature of a representative number of ce17 s?"
Data taken quarterly per Technical Specification Surveillance Test ME-12, but not averaged.
7.b.5 "The float voltage of each ce77?
11 Yes Done per Technical Specification Surveillance Test ME-12.
7.b.6 "Visually inspect or measure resistance of terminals and connectors (including the connectors at the de bus}?"
Done every two years using Periodic & Predetermined Activity Control (PPAC) SPS016.
- 7. c "At least every 18 months are the fo17owing verified:
11 7.c.1 "Low resistance of each connection (by test}?"
Done every two years using Periodic & Predetermined Activity Control (PPAC) SPS016.
7.c.2 "Physical condition of the battery?"
Yes Done monthly per Technical Specification Surveillance Test ME-12.
7.c.3 "Battery charger capability to deliver rated ampere output to the de bus?"
Yes Done per Technical Specification Surveillance Test RE-83A and RE-838.
7.c.4 "The capability of the battery to deliver its design duty.cycle to the de bus?"
Yes Done per Technical Specification Surveillance Test RE-83A and RE-838.
7.c.5 "Each individual cell voltage is within acceptable limits during the service test?"
Yes Done per Technical Specification Surveillance Test RE-83A and RE-838.
7.d "At least every 60 months, is capacity of each battery verified by performance of a discharge test?"
Yes Done per Technical Specification Surveillance Test FE-SA and FE-58.
7.e "At least annua77y, is the battery capacity verified by performance discharge test, if the battery shows signs of degradation or has reached 85% of the expected service life?"
Done every five years to a 80% level using Technical Specification Surveillance Test FE-5A and FE-58.
Batteries have not shown signs of degradation nor reached 85% of expected service life. Annual testing is not required.
8 "Does this plant have operational features such that following loss of one safety-related de power supply or bus:"
8.a "Capability is maintained for ensuring continued and adequate reactor cooling?"
Yes 8.b "Reactor coolant system integrity and isolation capability are maintained?"
8.c "Operating procedures, instrumentation (including indicators and annunciators), and control functions are adequate to initiate systems as required to maintain adequate core cooling?"
Yes
- 9.
"If the answer to any part of question 6, 7 or 8 is no, then provide your basis for not performing the maintenance, surveillance and test procedures described and/or the bases for not including the operational feature cited."
Information provided with each question that was answered 'no'.
Furthermore, the current design has been reviewed and accepted by the NRC.
See references 1, 2 and 3.
References
- 1.
Letter from DMCrutchfield (NRC) to DPHoffman (CPCo) dated May 26, 1981, "SEP Topic VIII-3.B, DC Power System Bus Voltage Monitoring and Annunciation, Safety Evaluation for Palisades."
- 2.
Letter from RAVincent (CPCo) to DMCrutchfield (NRC) dated July 14, 1981, "SEP Topic VIII-3.B, DC Power System Bus Voltage Monitoring and Annunciation."
- 3.
Letter from DMCrutchfield (NRC) to DPHoffman (CPCo) dated August 5, 1981, "SEP Topic VIII-3.B, DC Power System Bus Voltage Monitoring and Annunciation, Revised Safety Evaluation for Palisades."