ML20149H853

Forwards Revised Final Status Rept of Electrical Calculations Program for Facility,To Suppl . Rept Updates Status of Condition Adverse to Quality, Significant Condition & Problem Identification Repts

ML20149H853
Person / Time
Site:	Sequoyah
Issue date:	02/18/1988
From:	Gridley R TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
NUDOCS 8802220148
Download: ML20149H853 (12)

Text

'

i TENNESSEE VALLEY AUTHORITY '

CHATTANOOGA. TENNESSEE 374ol

$N 157B Lookout Place IFBB 181988 U.S. Nuclear Regulatory Commission '

ATTN: Document Control Desk Washington, D.C. 20555 Gentlemen:

In the Matter of ) Docket Nos. 50-327 Tennessee Valley Autherity ) 50-328 SEQUOYAH NUCLEAR PLANT (SQN) -

ELECTRICAL CALCULATIONS - REVISED FINAL STATUS FOR UNIT 2 RESTART

Reference:

TVA letter to NRC dated June 12, 1987, "Seouoyah Nuclear Plant

, (SQN) - Electrical Calculations - Revised Final Status Report"  ;

The purpose of this letter is to update NRC on the status of the electrical calculation program for SQN. It is a supplement to the referenced letter above and will (1) update the status of Condition Adverse to Quality Reports (CAQRs), Significant Condition Reports (SCRs), and Problem Identification Reports (PIRs) written as a result of the calculation program; (2) list new

' calculations performed since issuance of the referenced letter; (3) address the resolution of the unverified assumptions (UVAs); and (4) address postrestart work.

Enclosure 4 of the referenced letter defined a list of commitments to be satisfied by revising all essential minimum sets of calculations before restart. These are discussed below.

1. Verification of all previous UVAs.

SQN's Division of Nuclear Engineering (DNE) has addressed this issue by revising all essential minimum sets of calculations required to support '

unit 2 restart to either eliminate the UVA or provide justification in

, the calculation as to its acceptability for restart.

l

2. Deletion of nonconservative or unverified design cable lengths.

i calculations were revised to ensure that cable pull card data was utilized instead of design lengths. In the course of this effort, CAQR ,

1 SQP 871629 was written (see enclosure 2, page 6) and is being resolved in i j accordance with Nuclear Engineering Procedure 9.1, "Corrective Action."

The corrective action for unit 2 restart has been completed. I l

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' l 1 l 8802220148 880218 l PDR ADOCN 05000328 f

p DCD An Eowai Opportunity Employer

FEB 181988 U.S. Nuclear Regulatory Commission

3. Correction of deficiencies identified by the Design Baseline and Verification Program (DBVP).

Calculations have been revised to address punchlist items and CAQRs/SCRs '

generated by DBVP.

4 Incorporation of configurational control (as-constructed) drawings and applicable DBVP walkdown data.

Calculations were revised to include the DBVP walkdown data and marked-up ,

configurational control drawings, t

Enclosure 1 lists those new calculacions done since the referenced letter was '

a completed. It does not include revisions to the calculations listed in  :

l enclosure 2 of that letter. Enclosure 2 of this submittal is a revision to

) enclosure 3 of the referenced letter and updates the status of SCRs, CAQRs, and PIRs In addition. TVA would like to clarify a point that resulted from a question raised by Bechtel Corporation in their enclosure of Employee Concern No. i 213.01. Some calculations are not performed within the Sequoyah Engineering '

Project (SQEP). These calculations, which support relay setting cheets, are l issued by TVA's Power System Operations (PS0) of the Office of Power under their quality assurance program. Although these calculations are performed by PSO, it is the responsibility of the SQEP to review and approve these relay setting sheets before their implementation by PSO personnel for safety-related equipment. SQEP review does not verify the P30 calculation, but looks at these 9etpoints with respect to their impact on safety of the affected  ;

system. TVA feels clarification of this point is appropriate in order to '

prevent any misunderstanding between TVA and NRC concerning this item.

i Very truly yours.

4

[

i

] TENNESSEE V LEY AUTHORITY  ;

R. Cridley, rector i

! Nuclear Licensing and '

j Regulatory Affairs l

i j Enclosures '

1 cet See page 3 1

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U.S. Nuclear Regulatory Commission FEB 181988 cc (Enclosures):

Mr. K. P. Barr, Acting Assistant Director for Inspection Programs TVA Projects Division Office of Special Projects U.S. Nuclear Regulatory Commission Region II 101 Marietta Street. NW Suite 2900 Atlanta, Georgia 30323 Mr. C. C. Zech. Assistant Director for Projects Mall Stop 7E23 TVA Projects Division Office of Special Projects U.S. Nuclear Regulatory Commission 1920 Norfolk Avenue Bethesda, Maryland 20814

!)equoyah Resident Inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy Daisy. Tennessec 37379

I ENCLOSURE 1 i ,

I The following are additions to the Instrumentation and Control Calculations t Section. Item 9,, Instrument Setpoint Accuracy Calculations.

1 No. 001B (843 870828 915) . !

l t -

No.,002B (B43 871026 905) l No. 003B (843 860813 901)

No. 004B (B43 860721 903)

No. 006B (B43 870123 901)

No. 70 (B43 870901 914)

No. 71 (B43 870414 904) j No. 72 (B43 870421 903) i No. 73 (B43 870828 913)

! No. 74 (843 871106 906) i No. 75 (B43 870824 909)  !

No. 76 (843 87080/ 902)  !

. No. 77 (B43 870831 902) l No. 78 (B43 870901 906)  ;

No. 79 (843 870709 903)

No. 80 (B43 870914 901) -

No. 81 (B43 870729 904)

No. 82 (B43 870827 907) 4 No. 83 (B43 870901 911)  !

No. 84 (843 871001 917)

No. 85 (B43 871009 906) I No. 86 (B43 871012 901) '

! No. 87 (B43 871029 901)

No. 88 (B43 871127 914) i No. 89 (B43 871127 915) i No. 90 (B43 871201 901)  !

No. 27S1A l No. 2-FT-70-81A/81E The following are calculations added to their respective item numbers for tux 111ary Power System:

i Item 5 - SQN-E3-011 (DC Voltage Analysis)  !

t i

Item 9 - SQN-EPS-011 (Verification of tising Cable Pull !.engths in Voltage I

] Drop Calculations) i l

Item 11 - SQN-APS-004 (Electrical Equipment Ampacity) [

]

Item 14 - SQN-E3-011 (DG Voltage Analysis)  !

! The following are calculations added to their respective item number for  !

) Control Power System:

l Item 13 - SQN-APJ-010 (Class 1E MCC '.'ndervoltage)

I l Item 26 - SQN-CPS-013 (Cascade Tuse Analysis) i Item 26 - SQN-E3-003 (Class 1E MCC Control Power Transforner overload 1

l Protection) s I

1

)

. ~ _ . - -. _ . . . ._ -_. .. - . - _ _ . - _ - .. . - . _ - . ..

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'" f ENCLOSURE 2 i I

SEQUOYAH NUCLEAR PLANT (SQN) '

Corrective Action LTst of Condition Adverse'to Quality Reports (CAORs).

• j Significant Condition Resorts (SCRs). and Problem Identification Resorts fPIRs) i i.

l (Sheets 1 to ?). i J t a

Referenced notes for this enclosure (

, are located on the last page t

1 of this enclosure. j

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SQN - SCRs, PIRs, AND CAQEs FOR ELECTRIC p0WER SYSTEM CALCULATIONS

^

SCR SQNEEB8607R1 PROBLEM: Deficiencies exist with respect to individual components' voltage in the Class 1E auxiliary power system.

CORRECTIVE ACTION: Installation uf eight new cables and eight new 80-percent voltage solenoid valves. En61neering Change Notice (ECN)-L6648 See Note No. 1 SCR SQNEEB8532R3 PROBLEM: Deficiencies exist with respect to individual components' valtage in the 120-V ac vital instrument power system.

CORFECTIVE ACTION: Pulling larger size cable to reduce esbit i.epedance and paralleling supply cables to reduce ,

current through various portions of the affected circuits.

(ECNs-L6609, -L6663 -L6698)

See Note No. 1 SLR SQNEEB8605R1 PROBtEM: Inadequate minimum de input voltage for the unit 1 inverters and 26 miscellaneous solenoid valves at minimum battery terminal voltage.

CORPECTIVE ACTION: Recertification and testing of inverters determined that inverters will operatu properly with Twenty-four solenoids were recategorized available voltage. '

as now-required at minimum battery voltage. The remaining two solenoids were certified operable by the vendor with available voltage. No physical modifications were required. (ECN - N/A)

Closed (B25 870312 101)

SCR SQNEEB8629R4 PROBLEM: Diesel generator potential overload during blackr.ut concurrent with Phase B containment irolation because of random load block addition at T = 30 seconds.

CORRECTIVE ACTION: Addition of time-delay relays to ensure that random loading does not occur simultaneously at T = 30 seconds. (ECN-L6715)

See Note No. 1

SCR SQNEEB8665RO PROBLEM

Incorrect setpoints for vital battery boards I, II, '

III, IV, and V main breakers.

CORRECTIVE ACTION: Add redundant protective device or resize existing protective scher.e :.s required by Design Criteria

$QN-DC-V-11.3. (ECN-L6820) l See Note No. 1

. _ . _ _ _ _ _ . - _ _ _ .-_-_.-...._.._.._.._._____._.m ._ _ _ , _ _ _ . _ _ . _ _ . _ - - _ .

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j SCR I 1

SQNEEB8523R0 PROBLEN: Inadequate overcurrent protection for ten V3 '

! penetration circuits. '

j CORRECTIVE ACTION: Add redundant protective device or resize r ex' sting protectiv9 scheme as required by Design Criteria [

] SQN-DC-V-11.3. (ECN-L6606) f I

j c Closed (843 860123 907) I i

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! SCR j SQNEEB8675R0 PROBLE:1: Inadequate continuous current protection for

(Unit 1) electrical penetrations. (

i a

SQNEEB8677R0 CORRECTIVE ACTION: Obtain exception to Design Criteria 4

(Unit 2) SQN-DC-V-11.3 for electrical penetrations 52 and 53.  !

! (ECN - N/A)

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See Note No. 3 i t

i pIR SQNEEB8657R1 PROBLEM: Fifth vital battery system transfer switches ar- I l not adequately rated to withstand maximum ovallable fault l j current. '

CORRECTIVE ACTION

Corrective acticn has not yet been l i detemined. This system is not required for unit 2 restart.

i (ECM - N/A)  !

i >

i See Note No. 3

{

j SCR 6

SQNEEB8646R1 PROBLEM: Civen diesel generator breaker closure at 80-percent voltage and 850 r/ min and loads applied at Tao  !

(closure of the creaker), the voltage will dip below the  !

{

25-percent variance and will not recover +o 90 percent of  ;

nominal for 1.9 seconds for blackout with phase A isolation. i

{ CORRECTIVE ACTION: Based upon test results of Surveillance  !

Instruction (SI) 7 (performed January .!3.1986), breaker l l closure actually occurs when voltage is greater than '

( 100 percent of nominal. Thus, no deficiency exists and no j l corrective action is required. '

1

Closed (B25 870220 0,5) i i pIR 4

SQNEEB8666RO PROBLEM: The available fault current at the 6.9-kV unit

) boards exceeds the breaker's ratings for the following

} condition: Full load operation with power supplied from the Unit Service Station Transfomers (USSTs) and generator operating at 24.5 kV (673 MVA available).

90RRECTIVE ACTION: Corrective action was established under j SQ-DCR-p-1958. (ECN-Later) i

See Note No. 3 I

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SCR SQNEEB86124R0 PROBLEM: Maximum loss of coolant accident (LOCA) loading for control and auxiliary building vent boards 1Al-1, 2Al-A, and 2B1-B' exceeds the feeder breaker continuous current setpoints.

CORRECTIVE ACTION: Change feeder becaker setpoint (proposed). (ECN-L6883)

See Note No. 1 CAQR SQP870791 PROBLEM: The loud tabulations on 125-V de vital battery board single-line drawings 45N703-1R26 and 45N703-2R22 are incorrect relative to de emergency lighting loads.

CORRECT 1VE ACTION: Determine worst-case battery loading and revise calculation SQN-CPS-004 and the affected single-line drawings accordingly (proposed). (ECN-L7186)

See Note No. 1 SCR SQNEEBS6131R0 PROBLEM: Tabulated worst-case 2-hour loading on vital battery boards I, II, III, and IV panel 3 bus exceeds manufacturer's continuous current rating.

CORRECTIVE ACTION: Additional vendor data doeurented a 3-hour bus rating on panel 3 in excess of the 2-hour loading; thus, no corrective action is required.

Closed (B25 871007 019)

SCR SQNEEB86167R3 PROBLEM: This SCR documented three Cans: (1) Lack of selective coordination for 480-V essential raw cooling water (ERCW) boards and diecol auxiliary boards; (2) lack of overload protection for several 480-V IE loads (switchgear and motor control center); and (3) lack of adequate short-circuit protection for station deck su=p purpt A and B.

COIRECTIVE ACTION:

Proposed (1) Adjust breaker long delay pickup; Proposed (2) SCR SQNEEB86167 and PIR SQNEEB86192 identified two deficiencies with respect to thermal overload heaters (TOLS):

A. The TOLS for approximately 100 Class IE motors or valves were not .ized in accordance with the requirements of TVA i

4 Procedutw dethod (PF) 86-18 (TVA).

, B. The impedance of the TOLS for approximataly 100 Class 1E motors or valses proouced excessive voltage drop to the components, thereby potertially rendering the devices inoperable,

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As corrective action for the deficiencies, the following }

options were proposed and implemented as appropriate. l A. For motors, resize the TOL in accordance with the I requirements of PM 86-18 and in accordance with position  !

C.2 of Regulatory Guide 1.106, revision 1, March 1977. I B. For active valves not actuated by a safety injection (SI) I

, signal, bypass the TOL contacts in accordanca with i ECN-L6883 and technical specification (TS) change 87-29. f C. For SI-actuated valves, bypass the TOL in accordance with

, ECN-L6883 and TS change 87-29. This option in several ,

i cases reduced the circuit impedance significantly and ,

l resulted in the potential for a fault current to exist in '

excess of the associated circuit breaker interrupting rating. In these instances, the circuit breakers were l

j also replaced, ,

For corrective action options 2 and 3, applicable TSs shall -

be revised as required, f l

Proposed (3) Replace thermal magnetic breakers. i See Note No. 1 l PIR

, SQ:lEEB8668 PROBLEM: Pressure switches are not qualified to seismic l j category 1 requirements. Failure of these switches will  !

i cause the Main Control Room (MCR) air chillers to not perform e i their intended safety function.  !

! CORRECTIVE ACTION: Replace components or obtain seismic l

}

l qualification for existing components. >

j Seismic qualification obtstned in accordance with j

calculation SQEP-EMC2, "Seismic Qualification of Alarm Relay

Power Supply and Pressure Transmitters." No further action E

required.

I  !

., PIR PROBLEM: An interlock from the carbon dioxide (CO ) fif*

2 I

SQNEEB8628R0 protection system initiation signal that stops the diesel [

j generator room exhaust system is not seismic category 1 as ,

i required by the Final Safety Analysis Report (TSAR),  !

I section 9.4.5.3. I

.i  ;

CORRECTIVE ACTION: Replace components or obtain seismic

qualification for existing components. (ECW - Later) 1 See Note No. 3 I l

1 1

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s j PIR 3

SQNEEB8683R0 PROBLEH: Heater control circuits are not seismically qualified. Their f ailure can cause the heaters to turn on inadvertently, with the potential to heat the associated roots to an. unacceptable temperature. '

, g0RRECTIVE ACTION: Replace components or obtain seismic qualification for existing components. (ECH - Later)

I

' See Note No. 3 (Item has been transferred to the Mechanical Engineering Branch (MEB]).

! l SCR '

SQNEEB8667R0 PROBLEM: Air compressors were seismically qualified; however, qualification did not demonstrate that instrument

} setpoints would not have an unacceptable shift following a  :

i seismic event, j CORRECTIVE ACTION: Replace components or obtain seismic

) qualification for existing components. (ECN-L6878) r See Note No. 1 o

! l SCR

! SQNEEB8673R0 PROBLEMt High temperature shutdown interlock in either j shutdown board room A or B will shut down the l air-conditioning equipment for the opposite training board j room.

1 CORRECTIVE ACTION: Purther evaluation of system design has determined that problem does not exist.

l i Closed (B25 870404 106) i i i l SCR i

• SQNEEB8691R0 PROBLEM: A. pres'nt setpoint for instruments that start the traveling screen motors for the ERCW system is 90 PSIC.

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! Accuracy of these instruments is i 4.5 PSIG. Safety limits  !

?

' are lower = 70.5. upper . 70.9. Therefore, operational  ;

limits are violated even with a setpoint change. l i Corrective Acti;n: Leave the setpoint at 90 PSIC. Change  !

' the logic diagram as appropriate. Establish a yearly i surveillance requirement to censure the screen wash pump discharge pressure and river level. The upper operational ,

limit can be determined by using the equation given in l l "Su mary of Calculated Data" in DNE calculation. I "Demonstrated Accuracy Calculation." O-PS-67-471. revision 0 t

(843 870120 935). Initiate corrective action if the 4

discharge pressure falls below this upper limit.

t i PROBLEN: B. present setpoint for the ERCW backwash initiation is 2.0 PSID increasing; operational limit is 0.5 PSID. Therefore, the present setpoint violates the operational limit.

l CORRECTIVE ACTION: Setpoints must be changed. (ECN-L7291 l and -L7292).

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PROBLEM: C. Present setpoint for the ERCW backwash flush j

] initiation is 20.0 PSID increasing. Operational limit is i 34.0 PSID decreasing. Functional logic is incorrect, and {

! setpoint is in violation of operational limit, j CORRECTIVE ACTION: Setpoint must be changed, and operational limits need to be recalculated. (ECW-L7291 and -L7292) (

4 i

See Note No. 3  !

I I l SCR j SQNEEB8689R0 PROBLEM: A. Present setpoint for nonessential control air j

) isolation is 80 PSIG decretainst system design limit is j 83 PSIC. Instrument accuracy is 1,2.7 PSIC. l 4

CORRECTIVE ACTIOM: Reevaluate mechanical system design t limits and revise setpoint, if required. (ECN-L6878)  !

i  !

j PROBLEM: B. Present setpoint for starting and loading the l

{ essential air compressors is 75 PSIC decreasing; system i

) design limit is 73 PSIG. With insecuracles of 2.7 PSI.

system design limits could be violated.

]

1 CORRECTIVE ACTION: Reevaluate mechanical system design ,.

j limits and revise setpoint, if required. (ECN-L6878) (

l See Note No. 1 lt SCR SQUEEB8690R0 PROBLEM: A. The automatic control for the turbine-driven I feedwater pump is set for 880 gal / min. The setpoint to lock j out manual control is 800 gal / min or greater. Therefore, t i manual control is effectively presented. Operating i i procedures require manual control. i i CORRECTIVE ACTION: None. Reevaluated system operation with i i respect to design criteria and determined that a problem did f l not exist. (ECN - N/A) i PROBLEMt B. FS-46-57 has a reset adjust that must be set to f minimum to prevent lockup. EIs do not require this adjustment to be made.

CORRECTIVE ACTION: None. Reevaluated system operation with I I respect to design criteria and determined that a problem did {

not exist. (ECN-N/A)  !

i

! Closed (B25 870928 024)  !

CAQR SQP871608 PROBLEM: Required accuracy for the refueling water storage I l tank level Postaccident Monitoring (PAM) indicators is

) violated. {.

? CORRECTIVE AC.I1QN Recalibrate transmitter and revise SI to i require the equipment to be checked at a maximum frequency of l 18 months. f

, i-See Note No. 2 l I

4 I _ __ _ _ ___I

CAQR SQP871629 PROBLEM: Cable pull cards are not quality assurance documented.

CORRECTIVE ACTION: Perform a voltage sensitivity analysis by determining,the allowable voltage drop margin between the calculated voltage at the device terminals and the voltage required for device operation. Field is to verify those cable lengths where margin is nat significant (less than 70 percent). This item is required for unit 2 restart.

See Note No. 1 CAQR SQP871631 PROBLEM: Voltage drop calculation for the "diation monitoring equipment shows that the voltago .* quired to start equipment is below manufacturer recommendations.

CORRECTIVE ACTION: Prepare exception request for design criteria.

See Note No. 3 CAQR SQP871644 PROBLEM: The satpoints for the upper head injection level switches are inaccurate.

CORRECTIVE ACTION: The corrective action has been determined and will be issued and implemented after unit 2 restart. It was determined that the description of the CAQR did not apply to unit 2 restart.

See Note No. 3 NOTES:

1. The corrective actions for this CAQ/CAQR have been identified and implemented for unit 2. The design and fieldwork are coeplete for that portlon of the corrective action that is required for unit 2 restart. The remaining work that is required has been scheduled so a unit 2 postrestart item.

2. The corrective actions for this CAQ/CAQR have been identified and are scheduled as unit 2 restart items. The implementation of that portion that is required for unit 2 restart will be completed before restart; all remaining work will be scheduled accordingly.

3. The corrective actions for this CAQ/CAQR have been generally identified and are scheduled as postrestart items. The corrective action has been scheduled accordingly.