ML20043B174

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Application for Amends to Licenses NPF-11 & NPF-18,revising Single Largest Load Reject Value for Div III Diesel Generator & Clarifying Requirements for Automatic Bypassing of Diesel Generator Trips on ECCS Actuation Signal
ML20043B174
Person / Time
Site: LaSalle  Constellation icon.png
Issue date: 05/16/1990
From: Morgan W
COMMONWEALTH EDISON CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20043B175 List:
References
NUDOCS 9005250005
Download: ML20043B174 (8)
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\ Commonwealth Edison

., - i ) 1400 Cpus Plsce i ) Downers Crove, Illinois 60515

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May 16, 1990 p

L U.S. Nuclear Regulatory Commission i ATTN: Document Control Desk Washington, DC 20$$$

c St ab jec t s taSalle County Station Units I and 2

@, , Proposed Ament: ment to Technical Specification for heility operating Licence hos. EPF-11 and NPF-18 EBC_DockrA_Nea.,_50-373 amL50-374 .

F Reference (s): See Attachment D i 1

Dear Sir  ;

Pursuant to 10 CFR $0.90, Conanonwealth Edieon Company (CECO), is hereby applying for an amendment to Facility Operating License Nos. NPF-11 and NPF-18, Appendix A, Technical Specifications. The purpose of this  !

Technical Specification change is to revise the single largewt load reject  ;

value for the Division III Diesel Generator, and to clarify the requiremento for Automatic Bypassing of Diesel Generator Trips on an ECCS Actuation Signal.

Attachment A contains background information and justification for  ;

the proposed change. Attachmert B contains the proposed changes to the #

Technical Specifications. The proposed changes have been reviewed and "

approved by both On-Site and Off-Site Review committees in accordance with Commonwealth Edison Company procedures. This amendment request has been evaluated in accordance with 10 CFR $0.92(c) and it was determined that no ,

significant hazards consideration exists. That evaluation is documented in Attachment C. Attachment D lists other documents referenced in this submittal.

Commonwealth Edison is notifying the State of Illinois of our application for amendment by trnnomitting a copy of this letter to the .

I designated State Official.

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,9005250005900516 PDC I

- q, U.S. NRC- May 16, 1990 i

r Please direct any questions you may have regarding this matter to this office.

Very truly yours.

[

I 1 W Edu b Morgan '

Nuclear Licensing Adm'nistrator t s

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, , Attachmentu  ;

ect K. Pulsifer - Projeat Manager, NRh i E4 A. B. Davis Regional /.dmintutrator, R111 Senior Resident Ir.6pector - laStdie Office of Facility Safety - IDNS t

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TECEi10AluSEECIELCAllD!LAtimINENT REQUEST tmin c0UMILSIATHW UNITS 2 AMIL3 BACKGMUNILAND DISCUSE10N BACK0A01!ND During the August 1989 NRC Safety System Functional Inspection at LaSalle Station (Reference a) it was identified that a discrepancy existed between Technical Specification 4.8.1.1.2.d.2&3 and the Updated Final Safety Analysis Report (UTSAR) Table 8.3-1,regarding the value of the engineered safety feature (ESF) Division 3 " single largest load" and " full load rejection" tests. The single largest load value in the technical specification ic given as 2381 kW which equates to 3000 brake horse power (bhp)*, while the UFSAR gives the value as 3050 bhp. In the response to the NRC inspection report Commonwealth Edison committed (Reference b) to evaluate this discrepancy and to take any necessary corrective action. This evaluation (Exhibits 1&2) competed the technical specification load reject values for ESF Divisions 1, 2 and 3 with the values given in the UFSAR (References c, d and e). The evaluation determined that certain discrepancies t.xisted between the technical specification surveillance test values and the UFSAR design criteria given for the Division 3 " single largest load reject" and " full load reject" test. The Divisions 1 and 2 technical specification values were found to be consistent with the USTAR values. The Division 3 " full load reject" test value discrepaneles were corrected in the April 1990 Amendment to the UFSAR. This was done by revising the UFSAR Table 8.3-1 loads on Division 3 buses to more accurately reflect the bus loeds during a Unit 1 LOCA. The UFSAR Division 3 Unit 1 bun loading values were found to be more conservative than the technical specification surveillance value, this creating the discrepancy. To determine the loading, the actual name plate data was used where available and conservative data was used in the absence of available data. This submittal is proposing to revise the Technical Specification to resolve the

" single largest load reject" test value discrepancy. The appropriate station surveillance procedures for the Division 3 diesel generators have been revised to use the more conservative limits, and the diesel generators have been successfully tested using the new procedure revisions.

LaSalle Station is additionally proposing a Technical Specification change to clarify the requirements for the Automatic Bypassing of the Diesel Generator (D/G) trips on an ECOs Actuation Signal.

The station emergency power diesel generators at LaSalle Station have been equipped with the following automatic protective trips listed in Technical Specifications 4.8.1.1.2.d.7 and 4.8.1.1.2.d.13:

Engine overspeed, generator differential current, generator under frequency, low lube oil pressure, high jacket cooling temperature, generatoi reverse power. generator overcurrent, generator loss of field, and engine cranking lockout.

  • (using the HPCS pumps name plate efficiency rating of 94%)

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In addition to the above automatic trips the diesel generators are also equipped with emergency manual stop push buttons. These trips help to protect the diesel generators from damage due to failures of various system components, during normal operation. Under accident conditions (ECCS actuation signal present) all of the trips are required to be bypassed except for engine overspeed, generator differential current and the emergency manual stop. Technical Specifications 4.8.1.1.2.d.12 and 4.8.1.1.2.d.7 provide the requirements for periodically testing the i

operability of the D/G trips and the trip bypass circuitry. Technical Specification 4.6.1.1.2.d.7.b specifically outlines the surveillance requirements ior the Diesel Generators. This surveillance verifles that the D/G automatic trip 6 "except Lt.ose stated" are automatically bypassed on an ECCS a:tuatiot, signal.

The currm t 'lochnical Specification for the Division 3 D/G's specifies the following automatic trips as not bestag eutematically bypassed on s n FCCS ac';s tion signal. " Division 3 - engine overspeed, genere, tor ditterential or nercurren% and emergency tranual stop,"

As worded, the ste%:wnt is :nisleading and could be interpreted to (

waan that both t he acuerator dif f erentiel current trip end the, overcurrent trip are to be typassed on an ECC3 c.ctuation signal. 1his interpretation of the requiremrint is contrary to regulatory requirements and actuel plant design.

This submittal is proposing to clarify this Technical Specification Surveillance Requirement.

DISC 1!ES10H Technical Specification 4.8.1.1.2.d.2 tests the ability of the ESF Divisions 1, 2 and 3 diesel generators to reject a load equal to or greater than the " single largest load" on the bus without exceeding 75% of the difference between the nominal speed and the overspeed trip setpoint or 151 above the nominal speed, whichever is less. The Unit 1 and 2 high pressure core spray (IIPCS) pumps, are the largest loads on the ESF Division 3 Buses 143 and 243 respectively.

From the performance curves for the IIPCS pump in Figure 6.3-3 of the UFSAR (reference f) it was determined that the HPCS pumps can achieve a maximum brake horse power slightly in excess of 3000 bhp. This maximum value is between 3000 and 3500 bhp. UFSAR 'lables 8.1-7 & 8 rate the Unit I and 2 IIPCS pumps at 3000 bhp. UFSAR Table 8.3-1 indicates the coincidental loads for shutdown and LOCA operation and gives a higher value of 3050 bhp -

for the lipCS pumps. This value from Table 8.3-1 bounds the maximum brake horse power value determined from Figure 6.3-3 and thus provides a conservative value for use in determining the " single large load reject" test value. It is proposed that the technical specification value be increased to 2421 kW which equates to the more conservative UFSAR value

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of 3050 bhp *. The proposed amendment increases the Unit 1 and 2 technical specification surveillance " single large load reject" test value for the Division 3 diesel generators (Technical Specification 4.8.1.1.2.d.2) to the more conservative value specified in UPSAR Table 8.3-1. This enhancement to the test program will help to assure the reliability and availability of the Division 3 diesel generators under all operating conditions. This enhancement will be accomplished by ensuring that the technical specification load reject test value is equel to or greater than the maximum load requirement for the HPCS pump which is the single largest Division 3 load.

In the Safety Evaluation Report (SER) for LaSalle Station (ref erence h, Section 8.3.1.1(3)), the diesel generator protective trip bypass system was evaluated. The SER required that the LaSalle diesel generator protective trip bypass system design meet the positions set forth in Branch Technical Position BTP ISCB-17 (reference 1), in order to minimita the potential for a false diesel genetator trip during accident conditions. The I BTP fa paragraph B.1 specifIcally stetes that, "The design nf standby diesel generator systems should retain only the engine overspeed and the generator differential trips and bypass all other trips under accident conditions.

Revision 2 of the ETP (reference j) indiccted that the BTP had been superceeded by Position 7 of Reguistory Culde 1.9 (reference g). The I requitementr, outlined in the Regulatory Guide are bacleally the same as the BTP, which is consistent with the LaSalle Station design for the Division 3 diesel generator protective trip bypass system. This design being that all i Division 3 diesel generator trips are bypassed under accident conditions with the exception of the engine overspeed, generator differential current and the emergency manual stop.

Based on this discussion it is proposed that Technical Specification 4.8.1.1.2.d.7.b for Units 1 and 2 be amended to clearly state that all trips are to be bypasses under accident conditions except fort engine overspeed, generator differential current and the emergency manual stop button.

  • (using the HPCS pumps name plate efficiency rating of 94%)

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EXHIBIT'1

  • Page.1 of 2 Diesel Generator Sing 1 ? bar"!c Load Reject Diesel Generator 0 1A 2A IB' 23 Single Largest Load LPCS Pump MR Pump RHR Pump HPCS Pump WCS Pump 1/2E21-C00l* Ic12-CG02B 2E12-C0028 lE22-C001 2E22-C001 Sources Pump Brake Horsepower U/FSAR 1500 lip 8100 ISP 800 HP Table 8.1-7 and 8 3000 HP 3000 W U/FSAR 1490 HP 765 I!P 765 HP Table 8.3-1 3050 HP Table Not Applicable Vendor Pump Curve Design Point 1480 HP 763 UP 760 HP Max Curve Point 1483 IIP Not Shown 2695 MP 773 HP 775 HP 3035 HP 3031 HP Max Data Point 1491 HP 775 HP 769 HP 3000 HP 3031 HP ELMS # 1490 HP 755 lP 765 HP 3050 HP 3000 HP Compa r ison Brake HP Used for Tech Spec Comparison 1491 HP 775 IIP 775 HP 3050 HP o

3050 HP Pump Motor Ef f f rom ELMS (nameplate data) 94% 93.31 93.34 94% 944 Power into Motor from DG 1586 HP 831 Hid 831 HP 3245 HP 3245 HP Conve r ted to KW 1182 KW 619 KW 619 KW 2421 KW 2421 KW Tech Spec Surveillance 1190 KW 635 5W 638 KW 2381 KW 2381 KW (4. 8.1.1. 2.d . 2) i Tech Spec Adequate? Yes Yes Yes No No Recommendation -

Revise Tech Spec Surveillance l from 2381 KW to 2421 KW g Electrical Loads Monitoring System - Data Base for Tracking Electrical Loads and Interconnections.

. . . .. . _ . , _ . . , , . - . __ _:-. -- . . _ . . - . . , _ _ . _ , _ - - - . . _ . ~ . - _ _ _ . _ _ _ _ . . = . _ . _ _ _ _ _ . _ ._

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g, EXHIBIT -.1 ;

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Diesel Generator. Single - Large Load - Reject

  • 2E21-C001 power requirements are higher, more conservative, than IE21-C001 and so are shown in this table.
    • ELMS 2E22-C001 brake horsepower value will be revised to ~ 3050 HP to conservatively account for the pump curve by using the pumpts aaximum power plus so:se margin for graph reading difficulty.

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  • EXHIBIT 2

,t Diesel Generator Full Load Reject c': ,

Division 1 Division 3  ;

Division 2 DG Ratings UFS AR Table 8. 3-3  ;

30-Minute 3040 KW 3040 KW 3040 KW 7-Day 2987 KW 2987 KW 2987 KW 2000-Hour 2860 KW 2860 KW 2860 KW t Continuous 2600 KW 2600 KW 2600 KW -;

E Tech Spec .

Surveillance 2600 KW 2600 KW 2600 KW

( 4. 8.1.1. 2. d . 3) i r

i UFSAR T3 Ole 8.3-1 (values for the-  ;

gresster of Unit '

1 prA 2 3us Load) 21.66 KW 2612 KW* 2719 KW Tech Spec a ' Adequate? Yes Yes Mo ,

Bus load using ELMS loads, e f ficiencies and power factors -- --

2597 KW Tech Spee Adequate with UPSAR Table 8.3-1 revised to 2597 KW7 -- --

Yes Recommundation -- --

Revise UFSAR Table 8.3-1 Division 3 load values using ELMS data

  • Approximately 57% of the listed Unit 2 Division 2 loads are to be manually operated as required within the diesel generator rating.

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