ML20236A788
| ML20236A788 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 03/06/1989 |
| From: | Kowalski S PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20236A791 | List: |
| References | |
| NUDOCS 8903200164 | |
| Download: ML20236A788 (5) | |
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wA, PHILADELPHIA ELECTRIC COMPANY:
2301 MARKET STREET P.O. BOX 8699 j
o PHILADELPHIA. PA.19101
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i (215) 841 4502 S. J. KOWALSKI. ' '
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vlC E-P FI E bl D E N Y March 6, 1989 i
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Docket Nos. 50-277 50-278 i
l U. S. Nuclear Regulatory Commission ATIN:
Document Control Desk' Washington, DC '20555
SUBJECT:
Response to NRC Questions Concerning Voltage Regulation Technical Specification Amendment Application (TSP 88-12)
REFERENCES:
1)
Letter from E. J. Bradley (PECo) to T. E. Murley (NRC) dated September 7,1988 2)
Meeting Summary from R. E. Martir (NRC) dated October 20, 1988 3)
Letter from J. W. Gallagher (PECo) to NRC dated January 26, 1989
Dear Sir:
In Reference 1, Philadelphia Electric Company submitted an Application to amend the Peach Bottom Technical Specifications.
The Application is a result of a revised voltage regulatiou study, and addresses the undervoltage protection scheme and the Etrergency Core Cooling System (ECCS) pump loading sequence. This Application was discussed with the NRC staff at a meeting on October 19,1988 (Reference I.).
The agenda from this meeting.is included as.
The purpose of this letter is to provide' the confirmatory information requested at the meeting and during the NRC Special Electrical Team Inspection (50-277/89-07 and 50-278/89-07).
The response below references the agenda item r. umbers used in Attachment 1 to this letter.
ITEMS 1 and 6:
Enclosed as Attachment 2 to this letter is a bound volume entitled " Peach Bottom Atomic Power Station Units 2 and 3 Voltage Regulation Study."
l This document includes the input assumptions and results of the study and addresses the adequacy of voltage protection at the 120V level.
This document was discussed with C. Morris (NRR technical reviewer) and T.
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Koshy (Region I inspector) during the recent Special Electrical Team Inspection.
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i ITEM 2*
i Enclosed as Attachment 3 to this letter is a bound volume entitled " Peach Bottom Atomic Power Station Units 2 and 3 Verification of Calculated Auxiliary Distribution System Voltages by Test."
This document defines the scope and results of the model validation test.
This was also j
discussed with the NRC during the Special Electrical Team Inspection.
ITEMS 3 and 9:
f PECo will revise the Updated Final Safety Analysis Report (UFSAR) to include the timing sequence of the following:
Emergency Service Water pumps, Emergency Cooling Water pump, tooling Tower pumps and fans, Diesel Generator room vent supply fans and the Residual Heat Remo. compartment coolers. This will be included in the next annual update to the UFSAR scheduled for submittal to the NRC by July 22, 1989. A list of the Surveillance Tests (ST) which address these loads with non-Technical Specification timers is included as Attachment 4 to this letter.
Appropriate revisions to these STs will be made following NRC approval of Reference 3.
Tnese revisions will be completed prior to restart.
ITEM 4:
PECo has developed an internal agreement between the Load Dispatcher and the plant operations staff which requires the Load Dispatcher to alert the Chief Operator at Peach Bottom if the 0.95 per unit (pu) emergency rating cannot be maintained.
The 0.95 pu bounds the value used in the Voltage Regulation Study. Upon receipt of the Lead Dispatcher's notification, the Chief Operator will separate both units from the affected source and declare that source inoperable, thereby invoking appropriate Technical Specification requirements for one inoperable offsite power source. This agreement will become effectise by March 10, 1989.
ITEM 5:
No additional information requested by the NRC.
ITEM 7:
No additional information requested 'a the NRC.
ITEM 8:
PECo has superceded, in its entirety, the original Technical Specification Amendment Application (Reference 1) by a revised Application (Reference 3).
The revised Application eliminates reliance upon the assumption that motor contactors will pick up at 75% of nominal voltage.
As described in detail in Reference 3, the proposed undervoltage protection scheme employs separate relays for LOCA and non-LOCA conditions. This modified scheme will ensure 85% of nominal voltage at the contactors during operation in a state other than the limiting condition LOCA.
For 460 volt equipment required to actuate under the limiting condition LOCA, a combination of modifications and testing are in progtess.
The modifications add interposing relays and/or replace control transformers which will ensure that the contactors will pick up when required, and the testing verifles that specific contactors pick up at less than or equal to 80% voltage. _ - _ _ _ _ _ _ _ _ _ - _ _.
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ADDITIONAL ITEM:
While discussing the Voltage Regulation Study during the Special l
Electrical Team Inspection, the NRC expressed concern with the i
possibility of overvoltage coaditions on the 480V buses.
In response to l
this concern, Philadelphia Electric has calculated the highest i
anticipated voltage on the 480V buses under lightly loaded conditions
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(both un!ts in long term shutdown) to be 1.06 pu on a 480V base.
The I
assumed loading for each 480V load center is 250KVA. The total load at the Class IE 4.16KV buses is SMVA, and the total load on each starting
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transformer is 7MVA.
The voltage on the 480V buses vill be approximately 1.12 pu on a 480V
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base immediately after tripping the cooling towar loads during normal plant operation. Within 70 seconds, by means of automatic load changer action, the voltage would be brought down to 1.10 pu on a 460V base.
Considering a nominal voltage drop between the 480V bus and the motors, the motor terminal voltage will be within +10% of the rating of the motors.
If you have any questions or require additional information, please do not hesitate to contact us.
l Sincerely,
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/f Attachments:
1.
Agenda from 10/19 meeting 2.
Peach Bottom Atomic Power Station Units 2 and 3 Voltage Regulation Study 3.
Peach Bottom Atomic Power Station Units 2 and 3 Verification of Calculated Auxiliary Distribution System Voltages by Test 4.
List of Surveillance Tests cc:
W. T. Russell, Administrator, Region I, USNRC (w/o Attachments 2 and 3)
R. E. Martin, Project Manager, USNRC C. Morris, Power Systems Branch, NRR, USNRC (w/o Attachments 2 and 3)
T. Koshy, Region I, USNRC (w/o Attachments 2 and 3)
T. P. Johnson, USNRC Senior Resident Inspector T. E. Hagette, State of Maryland (w/o Attachments 2 and 3)
T. M. Gerusky, Commonwealth of Pennsylvania (w/o Attachments 2 and 3)
J. Urban, Delmarva Power (w/o Attachments 2 and 3)
J. T. Boetcger, Public Service Electric & Gas (w/o Attachments 2 and 3)
H. C. Schwemm, Atlantic Electric (w/o Attachments 2 and 3)
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,J' Page 1 of l' Y
i AGENDA l
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1 1.
Discuss the results.of the revised voltage study which considers
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transients down to the 480 volt level.
I 2.
The predictions of the voltage transient study should be confimed by measurements (data) acceptable to the staff.
In Supplemental Information, i
Item 1, Model Validation, the licensee writes that measurements will be made.
l 3.
Whether.the start timing for loads on the 4160 volt 'or 13,800 volt buses l'
which can reduce transient voltages on the safety buses supplied by l
offsite power should be incorporated into the Technical Specifications.
These loads are:
Emergency Service Water and Emergency Cooling Water Pumos; Cooling Tower Pumos and Fans; Emergency Diesel Generator Room Vent Supply Fans; and the Residual Heat Removal Compartment Coolers.
4 Adequacy of the pre # erred power supply: Whether the preferred power supply voltages should be recorded, so that the frequency with which the voltage reaches, or goes below,.95 pu, the design basis minimum voltage and the duration of such excesses, is known.
5.
Discuss the preference to shift the timing of many systems versus selecting motors with the required torque at minimum voltage.
6.
One of the reasons for experiencing a80V bus vol.tages less than design basis minima, is said to be be:ause, at the time the Peach Bottom Atomic Power Station was designed, it was not customary to go below 4160 volts in design analysis, The revised voltage study goes to 480 volts.
Discuss assurance that there are no residual problems at 120 volts.
4 7.
All timing and minimum voltage specifications described in the proposed amendments are point values without reference to tolerances; or to drift in undervoltage and timing relay calibrations.
8.
Comitments from licensee to subject all contactors, relays and other hardware specified by plant design to work at a voltage less than :10%
of rated, to acceotance tests and to surveillance at intervals to be detemined, to ensure that components will continue to function outside manufacturers specified ranges.
9.
Discuss the current practice of dividing loads into Technical Specification loads and others not described in the Technical Specification, but which must be synchronized with them.
All leads which can influence the functional capability of safety systems should be accounted for.
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....4 ATTACHMENT 4 i
Page 1 of 1 List of Surveillance Tests for Loads with Non-Technical Specification Timers Emergency Service Water Pumps ST 8.1
" Diesel Generator Full Load Tests" I
ST 8.1.6
" Diesel Generator Annual Inspection Post Maintenance Test" ST 11.6-2 "D/G Simulated Auto Actuation and Load Acceptance for Unit 2" ST 11.6-3
" Diesel Generator Simulated Automatic Actuation and Load Acceptance Test - Unit 3" ST 13.11A
" Unit 2 - E12 4KV Undervoltage Relays Functional Test" ST 13.11B
" Unit 2 - E22 4KV Undervoltage Relays and E22 and E224 Alternative Shutdown Control Functional Test" ST 13.11.C
" Unit 2 - E32 4KV Undervoltage Relays Functional Test" ST 13.11D
" Unit 2 - E42 4KV Undervoltage Relays and E42 and E424 Alternative Shutdown Control Functional Test" ST 13.13.A
" Unit 3 E-13 Bus Undervoltage Relays Functional Test" ST 13.13B
" Unit 3 - E23 4KV Undervoltage Relays and E23/E234 Alternative Shutdown Control Functional Test" ST 13.13.C
" Unit 3 E-33, 4KV Bus Under Voltage Relays Functional Test" ST 13.13D
" Unit 3 - E43 4KV Undervoltage Relays and E43 and E434 Alternative Shutdown Control Functional Test" Emergency Cooling Water Pump Same procedures as ESW pumps plus:
ST 13.21
" Emergency Cooling Water Pump, Emergency Cooling Tower Fans, ESW Booster Pump Operability" Diesel Generator Vent Supply Fans ST 8.1
" Diesel Generator Full Load Tests" ST 8.1.6
" Diesel Generator Annual Inspection Post Maintenance Test" ST 8.1.11A-D "El-E4 Diesel Generator MCC Post Maintenance Logic Test" ST 8.1.12B "E2 Diesel Alternative Shutdown Control Functional" ST 8.1.12D "E4 Diesel and A ESW Pump Alternative Shutdown Control l
Functional" I
Residual Heat Removal Compartment Coolers i
ST 6.8 "RHR "A" Pump, Valve, Flow and Unit Cooler Functional" l
ST 6.8F "RHR ' A' Pump, Valve, Flow, and Unit Cooler Functional Flowtest" ST 6.9 "RHR
'B' Pump Valve Flow and Unit Cooler Functional l
ST 6.9F "RHR "B' Pump, Valve, Flow and Unit Cooler Functional Flow l
Test" Cooling Tower Lift Pumps ST 11.6-2 "D/G Simulated Auto Actuation and Load Acceptance for Unit 2" ST 11.6-3
" Diesel Generator Simulated Automatic Actuation and Load Acceptance Test - Unit 3"
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