ML17304A755

Analysis of Equipment Functionality W/Essential Chiller Sys Inoperable

ML17304A755
Person / Time
Site:	Palo Verde
Issue date:	11/07/1988
From:	ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:
Shared Package
ML17304A744	List: ML17304A743 ML17304A755 ML17304A760 ML17304A761 ML17304A762 ML17304A763 ML17304A769 ML17304A770 ML17304A771 ML17304A774
References
NUDOCS 8811220463
Download: ML17304A755 (48)

Text

'

E EXECUTIVE

SUMMARY

ANALYSIS OF E UIPMENT FUNCTIONALITY

'WITH ESSFNTIAL CHILLER SYSTEM INOPERABLE The E.C.

system consists of two 100% capacity, redundant, chilled water trains rated at 23S tons refrigeration each.

It provides chilled water to the essential HVAC systems in the ESP equipment and main control rooms.

With both chillers inoperable due to isolation of the flow transmitter by root valves (LER 1-88-017-00),

Engineering's analysis deter'.ined that:

i.,

All equipment would perform their intended function with the E.C.

system inoperable for 415 minutes (Reference Study 13-MS-AM, Revision 0).

'I 5 ii.

Equipment qualified life is shortened, but the decrease is not significant (Reference Calculation 13-EC-EC-200, Revision 1).

Based on an accident scenario of LOCA concurrent with

LOP, a

transient temperature calculation model was developed and temperatures were calculated for each room.

To verify the temperature rise calculated for. the control room by the model, a heat-up test was conducted inside the control"room.

This test provided a more realistic temperature rise and total heat load.

The test data was incorporated into a

separate calculation to modify the model and then recalculate the final room temperatures.

Based on the maximum evaluated temperature for individual

rooms, all safety related equipment was analyzed for functionality and loss of E.Q. life.

This analysis included, but is not limited to, bearing temperatures, lubricants, charcoal filter efficiencies, and tripping characteristics of electrical devices.

The equipment operating temperatures were obtained from proj ect specifications, existing vendor data, E.Q. reports and direct vendor contact.

11/7/88 SSii220463 SBii09 PDR AGOCK 05000528 P

PDC

~g(( QB 00('P~

PURPOSE THIS PRESENTATION IS TO OUTLINE THE ENGINEERI NG METHODOLOGYt LOGIC i ASSUMPTIONS AND END 'ESULTS IN THE ANALYSIS Of THE EC CHILLER INOP ERABILZTY.

THIS INFORMATION ZS TO PROVIDE THE INTERFACE BETWEEN-THE LER AND THE DETAILED EVALUATZONS PERFORMED BY ENGINEERING.

(.

fili'R ii/7/SS

Sco e

oE The Evaluation Engineering

'onducted an evaluation of the recent Essential Chiller inoperability to determine the safety significance and functionality of the equ pment in rooms whose HVAC equipment is supplied by the essential chilled water system.

The evaluation looked at the following.'etermine all the safety rooms.

related equipment within the affected 2.

'Perform transient temperature calculations for the affected rooms to establish an ANPP Model.

3.

Perform a

control room test to determine actual heat load and actual heat rate rise to be used to refine the ANPP model.

4.

Determine the functionality of the equipment at the refined maximum evaluated temperature calculated for each effecied room.

Determine the loss of qualified life as a result of the refined maximum evaluated temperatures calculated for each effected room 6.

Determine the confidence level of the operator response time.

o Mechanical, Electrical and Instrumentation

& Controls Evaluations Functionality review Equipment Qualification Evaluation Loss of EQ life PRA Evaluation Analysis of operator 'response time EED Evaluation j

Control room heat-up test Chiller start scenario gvJ 9

- 11/7/88'

0

ENGINEERING EVALUATION LOGIC TREE OESIGN INPUT 8c ASSUMPTIONS CONSERVATIVE MODEL ME-204 ANPP HEAT LOAD MODEL (HLM)

CONTROL ROOM HEAT-UP TEST ACTUAL HEAT LOADS AND HEAT RISE BENCH MARK ANPP HLM ALL OTHER ROOMS MODEL COMPUTER PLOTS TEMP. VS. TIME 8

ROOMS CONTROL ROOM MODEL REFINED ASSUMPTIONS

& INPUT TO HLM RERUN CONTROL ROOM "ANPP MODEL Y(ITH REFINED INPUT & ASSUMPTIONS REFINED CONTROL ROOM MODEL EQUIPMENT LIST EO DATA BASE EVALUATE EQUIPMENT BY CALCS,STUDIES, VENDOR DATA, TEST DATA LIMITING ELAPSED.

TIME CHILLER

'TART EVAL.

~

L.E.R.

SAFETY EVALUATION NO SAFETY CONSEQUENCES OR IMPLICATIONS.ARISE DURING PERIOD CHIL'LERS

~

Y(ERE INOPERABLE IIIv'R 11 /

/QQ

VI 1

I',

II

ANPP Heat Load Model HLM

~ln uts Actual initial air and wall temperatures with normal HVAC operating.

Heat loads from equipment, lighting and personnel-were taken from the design calculations.

Room volumes and surface areas.

Chilled water system characteristics.

Assum tions 0

Accident scenario large break

LOCA, concurrent with LOP was chosen to model the most safety related equipment in operation.

Although LOP was assumed,,

some normal operating equipment heat loads such as cabinet area, communications area were assumed.

Miscellaneous metal fixtures, e.g.,

structural

steel, platforms,

desks, were not included as heat sinks.

Constant conservative thermal properties were assumed.

100% of essential equipment heat loads were included at time 0.

Model Model results in a system of 17 first order ordinary differential equations which were integrated numerically by computer.

Model was benchmarked against the ME204 Design

Program, the conservative design model used at Palo Verde.

~ The ANPP model was found to be 98% accurate as compared to the ME204 Program.

Chilled water heat transfer was set to zero during the benchmark to be consistent with the ME204 Program.

Result's 0

Conservative values of room temperatures.

Found the limiting room, base'd on conservative room temperatures, to be the control room.

Conservative temperatures for all other rooms except control room are used to evaluate the safety related equipment functionality.

II'4'R 11/7/8S

0

ANPP HEAT LOAD L

Q

= HEAT ABSORBED BY CONCRETE (FRm K 204)

QQ= HEAT LOAD GENERATED BY EQUIPMENT (FRCM K 204 OR HEAT-UP, TEST)

RATE OF ENERGY ABSORBED BY AIR EQ C

('I Q'i'I = HEAT LOAD ABSORBED OR RELEASED BY EC SYSTEi'1 (VENDOR DATA)

AiVPP HEAT LOAD MODEL BENCHMARK Com arison with ME204 at 90 Minutes Room Auxiliary Feed Pump Containment Spray Pump Control Electrical Penetration EV Pump HPSI LPSI Switchgear ANPP HLM AVG W 'F b TIME 1.374

1. 684 1.409

.349 1.513 1.863

'1. 684

.835 ME204 AVG 6 F

TIME 1.391 1-.720 1.416

.343 1.546 1.758 1.720

.826 Variance

l. 24 2.14 0.50 (1.72) 2.18 (5.64) 2'4 (1.08)

HMR 1l/7/8S

r U

I%

}

0'

104 I

ANPP/ME.204 MODEL COMPARISON TYPICAL BENCHMARK-ELECT PENE ROOM 103 102 101 100 99 98

.97 95 93 99 -q 0

20 40 60 80 100 120 ANPP MODEL ZME (MIN)

+

ME-204 MODEL

Control Room Heat-U Test

~Pur ose The test purpose was to determine the actual rate of temperature increase over time for the control room to compare with the rate of increase calculated by the ANPP Heat Load Hodel.

Initial Conditions Test.

was performed in the Unit 1

control room during an unscheduled outage to measure the actual temperature increase and verify heat loads.

Test was performed without chilled water flow and with one control room essential fan operating.

Control room temperature was lowered to 62.5'F so a 15'F rise could be experienced without exceeding the design maximum ambient room temperature of 80'F.

Control room was maintained at approximately 60'F for a

70 hour8.101852e-4 days <br />0.0194 hours <br />1.157407e-4 weeks <br />2.6635e-5 months <br /> stabilization period prior to the test.

Tested Parameters Temperatures were taken at 10 equipment locations over a 58 minute time period.

Steady state heat balance analysis was performed to verify control room equipment heat load.

Results Control Room temperature actually increased by 12.5'F in 58 minutes versus the calculated rise of 32.5'F in 58 minutes for the same operating conditions.

The ANPP HLf is conservative versus the actual control room temperature test.

1R

I

130 CONTROL ROOM TEMPERATURE 1 FAN-NO EC FLOW 120 1,.10 100 CONSERVATIVE ANPP HEAT LOAD MODEL 90

'80 70 CONTROL ROOM HEATUP TEST 60 0

20 TIME (MIN) 40 60

Refined Control Room HLM

~In ues Actual initial room air and wall temperatures with normal HVAC operating.

Heat loads from equipment, lighting and personnel were reduced from the desi n values to the actual test heat load data.

Room volumes and surface areas.

Chilled Mater System characteristics.

ssum tions Accident scenario-large break LOCA, concurrent with LOP, was chosen to model the most safety related equipment in operation.

Although LOP was assumed some normal operating equipment heat load such as cabinet area, communications area.were included in the test and included in the model.

Additional heat sinks were

modeled, such as structural

steel, platforms, etc.

Constant but realistic thermal ro erties were assumed.

100% of equipment heat loads included at time - 0.

Heat loss bv radiation was modeled.

Chilled water heat transfer was set to zero to be consistent with the actual test data.

Results This results in a realistic best estimate model producing temperatures approximately 8'F greater than the heat-up test; which removed the conservative inputs and assumptions.

130 CONTROL ROOM TEMPERATURE

1. FANNO EC FLOW 120 110 100 CONSERVATIVE ANPP HEAT LOAD MODEL 90 80 REALISTIC ANPP HEAT LOAD MODEL 70 CONTROL ROOM HEATUP TEST 60 0

20 TlME (MIN) 40 60

N

Final Pro ram Hodelin For the Cont o

oo Heat Load Control Room Refined HLM was run with 75.5'F initial temperature.

\\

Two Control Room fans were running vs.

the one fan in the heat-up test.

EC chilled water was modeled into all rooms by a heat balance method to simulate actual condition from the event.

le'R

)> /

~ /MR

CONTROL ROOM TEMPERATURE 130 120 119 F

110 100 90 80

70 0

TlME (rnlnutes) 415 570

E ui ment Evaluated for Functionality Reviewed all Qualified Equipment Types of equipment evaluated Pumps Fans Electrical Switchgear I&C Cabinets and Local Instruments Transformers Motors Dampers Equipment Evaluation Based on Calculated Maximum Evaluated Room Temperature to Determine Functionality Equipment Bearing Temperatures Equipment Lubricants Effects on Charcoal Filters Tripping Characteristics of Electrical Devices Vendor Data on all Equipment Reduction in EQ Life for all Equipment Operating temperatures of equipment were obtained from:

Project Specifications Vendor Data Equipment Qualification Reports Direct Vendor Technical Contact

II 0

LIMITING FLAPSFD TIME TO REACH POSTULATED FUNCTIONALITY LIi!IT I

1 I

I I

Room I

I Temp. of Other Rooms)

When Control Room Reaches Postulated Functionality Limit

'F 6 Hr'5 Min c

Room Temperature Limit For Postulated Functionality Limit Temp. Limit oF Total Time To Reach

Limiting, Component Temperature HR'MIN c

I Aux. Feed I

) Cntmt.

Spray l Control I Elec.

Pen.

EW Pump HPSI I

I LPSI I

Swgr I

134.4 133.2 119.0 109.1 131. 0 136.2 135.8 119.2 131 164.3 159.8 135.8 122 l

(b) l (b)

I (b)

't" I

(b)

I I

(b)

I l

140.0 (a) 135.8 (b) 119 (a) 10:35 8:17 6:55 I

>24:00 I

I

>24:00 I

I

>24:00 I

l 6:55

(

I 8:37 I

1 I

All times from accident at time - 0

Reference:

a.

13-JS-A05 b.

13-EC-EC-200 c.

13-HC-EC-253

Conclusions Engineering's evaluation of equipment functionality of 415 minutes following the postulated accident scenario described concludes that:

With the EC system inoperable as described, the operating electrical and mechanical equipment in all areas served by essential chilled water will not significantly degrade at the elevated room temperatures and will perform their functions.

2.

Equipment qualified life is shortened during the time period the room temperature is above design basis.

However, this decrease in qualified life is negligible and not significant (Reference 13-EC-EC-200, Revision 1).

3.

Reliable operation of plant solid state instrumentation and control (Z&C) equipment is considered to be the limiting factor based on external cabinet temperature.

However, all ANPP cabinets (CAB) or the solid state Z&C components which they contain and that are required to function during the assumed

.postulated accident scenario have been qualified in excess of..the external cabinet temperature.

Therefore based upon ANPP's engineering evaluation, the safety consequences and implications arising from the event described in the LER are considered to be minimal.

l tl 4

ESSENTIAL CHILLED MATER SYSTEM EC EC System Consists Of:

Two, 100 percent-capacity, redundant, chilled water trains.

0 Chillers are self-contained, packaged refrigeration type with Each chiller has a rated capacity of 235 tons refrigeration.

The essential chilled water (EC) system supplies chilled water to the essential

heating, ventilating, and air-conditioning (HVAC) systems for control building, auxiliary building, and main steam support structure.

Roars ESF Switchgear Control Design Room/Air T~em -'F 104 80 Auxiliary Feedwater Pump I

EM Pump Electrical Penetration LPSI Pump HPSI Pump 120 104 104 104 104 CS Pump 104 DC Equipment 104 Design room air temperatures fiom project" Design Criteria Manual.

e IIllR

)I/7/88

I I

I I

I ESSENTIAL ACU HAA 03 I

I I

3C SSENTIA ACU HAA ZOI I

I

~P~MP f/~

ESSENT I AL ACU HAA-Z02 3C I

I 3

C I

I I

ELEC PENETRATION QQQ~~

ESSENTIAL ACU HAA-Z06 ESSENTIAL ACU HAA-Z05 X F WAT PUMP ROOM ESSENTIAL ACU HAA Z04 CONTROL ROOM ESSENTIAL ACU HJA-F04 I

I

(

I 3C CHANNEL "A" DC EOUIPMENT ROOM ESSENTIAL ACU HJA Z04 C

I I

I ESF SWITCHGEAR ROOM ESSENTIAL AHU HJA-Z03 DEMINERAL I ZED WATER STORAGE TANK

~HM AOO TANK ECN X01A CONDENSATE TANK TRANS'UMPS SERV ICE GASES l Ng )

80 GAL ~

65 PSIG

/@ANT A

CHILLEO H>0 EXPANSION I ANK ECA-TOI

'57 EF..

400 GPM IOO FT 235 ION ESSENT IAL CHILLEO wATER c IRcULAf loN PlwP ECA AOI A

ESSENT l AL-CHIL'LED-WATER SYSTEtv(

(ONE TRAIN)

ESSF.II V I al.

LHILLER EC*- Ol 44 ~F, II'4'R l~ ((A()

C Mechanical Evaluation En inee in Evaluation ANPP Heat Load Model - Calculation 13-MC-EC-253, Rev. 2'.

Su ort Calculations Descr'ion 13-MC-HA-252, Rev.

0 - Electric Penetration Room Transient Temperature S tudy 13-MC-HA-253, Rev.

0 -

EW Pump Room Transient Temperature Study 13-MC-HA-A02, Rev.

0 - HPSI Pump Room Transient Temperature Study 13-MC-HA-A03, Rev.

0 - Aux. Feed Pump B Room Transient Temperature Study 13-MC-HA-A05, Rev.

0 - Containment Spray Pump Room Transient Temperature Study 13-MC-HJ-253, Rev.

0 - Main Control Room Transient Temperature Study 13-MC-HJ-254, Rev.

0 -'SF Switchgear Room Transient Temperature Study 13-MC-HJ-255, Rev.

0 - Control Room Heat Load Calculation Mechanical E'quipment Evaluations

- Study 13-MS-A13, Rev.

0, Mechanical Equipment Operability Review with EC System Unavailable for 415 minutes and Calculation 13-MC-ZZ-202, Rev.

0, Bearing Temperature Calculation for AFA-P01 and SIA/B-P01 Motors, including CCN No. 1.

Bearing Temperatures for pumps,

fans, motors and dampers Lubricants Charcoal Filters Dampers ESF room design basis temp restoration

- Calculation 13-MC-ZZ-201, Rev.

0 Conclusions Continued bearing operations for rotating mechanical equipment is highly dependent upon the operating temperature limits of the grease.

Grease temperature limits for this safety equipment range from 275 F

to 450'F.

Calculated maximum temperature for the equipment without HVAC, ranges from 198'F to 335'F, well within the capabilities of the grease.

I Dampers operation during accident conditions requires only one time movement.

Mechanical components can adequately accomplish this short time function without being compromised.

~ Fire dampers activate at 160'F.

All room temperatures are below this 'activation'emperature.

Charcoal filters were tested. for their design erficiency to 176 F

(80 C) and wi'll perform,theii intended function.

Hli'R

>1/7/SS

i

Envineezinv Evaluation Instrumentation Controls Evaluation Instrumentation

& Controls Equipment

- Study 13-JS-AO(5 I&C. Equipment l&C Panels/Cabinets Implementing Documents/Sources EQ Engineering Revelation Database Control room heat-up evaluation Letter 167-02653-MFH/HWR and Calculation No.

13-MC-EC-253 to include Calculation Change Notices No.

1 and,2 Conclusions All individual I&C equipment/components that are located in the subject rooms which were impacted by the loss of essential chillers were determined to have no impact to functionality or safety significance as all components were either specified or qualified to temperatures equal to or in excess of the ambient temperatures postulated post accident (T>>

at 415 minutes).

All I&C panels/cabinets in the same aforementioned rooms ware also looked at.

Onl'y those panels/cabinets that were necessary to mitigate, and/or monitor the accident or perform safe shutdown of the plant were considered.

All of the panels/cabinets reside in the control room.

It was also determined that there was no functionality or safety significance as all panels were qualified to ambient temperatures equal.to or in excess of the TPP>

il i

ll

En ineerin Evaluation Electrical Evaluatio Tripping characteristics of elec.

devices based on T><<g Max. ambient temp on electrical equipment basis Vendor data review based on T><<g at 415 min References Calculations:

13-EC-EC-200 13-EC-MC-f53&~

Equipment Qualification Reports Vendor Product Literature Conclusio There are no functionality/operability difficulties for the equipment investigated during the transition from To <<

o to Tz 415 minutes.

If functionality is preserved in the safety related equipment, then it follows that there can be no safety significance to the occurrence, provided that the essential chilled system is restored at 415 minutes.

The postulated ambient room temperatures will not cause premature tripping of breakers or increased clearing time on fuses in circuits operating normally.

~

lib'R ll/7/88

t

Risk and Reliabilit Evaluation 0 erator Res onse Evaluations 0

Operations

Response

for isolation of EC Flow Transmitters Calculation NC-EC-200, Rev.

0 Maintenance

Response

for manual restart of EC Chiller Calculation 13-NC-EC-201, Rev.

0 Conclusions Operations response to diagnose and restore the EC Chiller following isolation of its flow transmitter is estimated-to occur within 130 minutes (95% response time)

Maintenance response to diagnose EC Chiller fail to start and perform a

manual chiller restart is estimated to"occur within 320 minutes (95'4 response time)

I

SUMMARY

ANALYSIS TECHNICIAN EXPOSURE SEQUENCE TASK/DESCRIPTION LOCATION DURATION (MIN)

WHOIE BODY THYROID DOSE DOSE (REM)

(REM)

EVACUATION EVACUATION ACCOUNTABILITY RETURN TO UNIT REPORTING TO OSC 86 (A)l RESPIRATOR ISSUE I

I (B)l TRANSIENT TO I

CONTROL BLDG I

(C)l BACK TO EOF BLDG AUX ANNEX ANNEX TO SERVICE SERVICE TO AUX AUX BLDG CONTROL BLDG TO ANNEX 15 10 20 10 7.5 1.25 0.33

0. 63 0.63

0. 05

7. 88

1. 25 33.3 27.8

16. 65

16. 65 410 CLOSE OUT PAPER WORK 6 OTHERS EOF 60

0. 05 TOTAL DOSE CRITERIA FOR EMERGENCY CORRECTION ACTION (EPIP 18) 20 25 106 125 Respirator

+

Dose not calculat'ed, 'release to AUX. Building is minimal.

0'