Information Notice 1989-30, High Temperature Environments at Nuclear Power Plants

High Temperature Environments at Nuclear Power Plants

ML031180725
Person / Time
Site:	Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Mcguire, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Three Mile Island, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant
Issue date:	11/01/1990
From:	Rossi C Office of Nuclear Reactor Regulation
To:
References
IN-89-030, NUDOCS 9010260154
Download: ML031180725 (8)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 November 1, 1990

NRC INFORMATION NOTICE NO. 89-30, SUPPLEMENT 1: HIGH TEMPERATURE ENVIRONMENTS

AT NUCLEAR POWER PLANTS

Addressees

All holders of operating licenses or construction permits for nuclear power

reactors.

Purpose

This information notice supplement is being provided to present additional

information regarding the effects of elevated room temperature on the

operability of safety related equipment as discussed in NRC Information Notice 89-30, issued March 15, 1989. It is expected that recipients will review the

information for applicability to their facilities and consider actions, as

appropriate, to avoid similar problems. However, suggestions contained in

this information notice do not constitute NRC requirements; therefore, no

specific action or written response is required.

Description of Circumstances

Information Notice No. 89-30 described events where elevated temperatures and

high humidity within the drywell or containment adversely impacted the

operability of safety related equipment.. This supplement describes events

where high ambient temperatures in areas other than the containment or the

drywell caused the failure or degradation of'safety related equipment.

On June 25, 1990, the Omaha Public Power District (the licensee) conducted a

full load test on the No. 1 emergency diesel generator (EDG) at Fort Calhoun

Unit 1. This test was conducted to establish a temperature profile for the'

EDG room. The test was terminated when the output from the generator became

erratic as a result of the failure of a transistor in the static exciter

circuitry.

The licensee's investigationlrevealed that the transistor had failed because of

the effects of elevated temperatures in the static exciter/voltage regulator

cabinet which was located in the EDG room. Temperatures in the cabinet had

reached 140 degrees Fahrenheit (F) during the test. The transistor was-replaced

and the EDG was returned to operable status. The licensee also discovered

elevated temperatures in the static exciter/voltage regulator cabinet for the

No. 2 EDG. In a recently completed engineering analysis, the licensee verified

that because of inadequate cabinet ventilation, a potential common mode failure

of both EDGs exists. The analysis also concluded that this condition has likely

existed since plant startup.

t 91060154_Z>'

Ir I IN, I... I IN b-,30, Supplement I

November 1, 1990 To reduce the potential for heat bujildup in the cabinets, the cabinet doors were

temporarily--removed until a long term solution to the. problem can be formulated.

The licensee's investigation of this event also revealed that elevated room tem- peratures significantly impact the operating efficiency of the EDGs and could

lead to accelerated degradation.

Discussion:

The Fort Calhoun Station has two General Motors EMD 20-645E4,diesel generator

sets. The cooling system for each EDG consists of an engine radiator, an

engine-driven fan, and a.pump that circulates cooling water through the engine

and radiator. Outside air is drawn into the EDG room by the fan, is blown

across the radiator, and exits through the roof of the building through air

ducts. Inlet air for the diesel turbocharger is drawn directly from the EDG

room.

In June 1988 the licensee modified the hangers on the diesel'exhaust headers.

These modifications required that the insulating material on the

headers be removed. After removing the insulating material, the licensee

was aware'that ambient temperature would increase. Therefore, the licensee

performed an analysis to support a design change that would allow the exhaust

headers to remain uninsulated. The analysis concluded that bulk temperature in

the EDG rooms would rise by only 9 degrees F and that this increase would not

have an adverse effect on the operability of the EDGs. The analysis did not ": I

' specfically ddresthei'effect"of elevated room temperature on other equipment-

:: ", .

1

• !' '

, I 2.

-located infthe room.: ' .. -  ; .

When test runs were made during the summer months of 1989, the licensee found

that bulk room temperatures actually increased approximately 20 degrees F, or

more than twice the increase'predicted by the licensee's analysis. This ele- vated room temperature likely accelerated the degradation of the exciter com-,

ponent that failed. However, the potential for the temperature buildup in the

unvented cabinet probably existed since the cabinets were installed.

The licensee also has determined that the 20 degree rise in ambient temperature

resulted in an increase in jacket water temperature and turbocharger. inlet air

temperature., These temperature increases adversely affect engine operating

efficiency. Depending on the amount of increase, elevated jacket water

temperature and/or turbocharger inlet air temperature, combined with heavy

loading, may lead to accelerated degradation of the engine. This degradation

could result in engine failure or prevent the engine from meeting its designed

run time as assumed in the Final Safety Analysis Report. To reduce the poten- tial for engine degradation while operating during periods of high ambient

temperatures, unit loading would have to be limited. Derating the EDG could

result in the unit's dependable output capability being less than required for

design basis accident loads.

Because of variations in the configurations of intake air systems, turbocharger

inlet air may be preheated significantly. The temperature of the air entering

the turbocharger may be much.higher than air temperature elsewhere. ,Also,,

water-to-air heat exchangers are more sensitive to changes in ambient temperature

IN E 30, Supplement 1 November 1, 1990 than are water-to-water heat exchangers. However, an increase in service water

temperature in water-to-water heat exchangers may also result in the derating

of an EDG. The NRC is!aware of other instances in which elevated ambient tempv- eratures resulted in the failure or degradation of safety related components.

To avoid excessive cabinet temperatures and subsequent component failures, the

licensee for the Washington Nuclear Project, Unit 2, has instituted admin- istrative procedures to remove the doors from the static exciter voltage

regulator cabinet when the EDG room temperature exceeds 90 degrees F. The

licensee performed an analysis which concluded that internal temperatures in

the cabinets would exceed the long-term (greater than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />) thermal'rating

of the cabinet components if'the EDG room temperature were to exceed 90 degrees F.

Extended operation at or above this temperature would significantly increase the

probability of a component failure.

On December 16, 1985, the failure of a fan in an engineered safety features

(ESF) cabinet at Palo Verde Unit 1 resulted in the spurious actuation of several

ESF signals. These signals initiated the automatic start of the Train A EDG,-

caused loads to be shed from the"Train A vital bus, and initiated the operation

of the ESF load sequencer. The load shed signal did not clear, prohibiting the

automatic or manual sequencing of ESF electrical loads. The licensee installed, a control room alarm that annunciates on cabinet exit air high temperature.

On June 4, 1984, at the McGuire Station, a total loss of control area ventilation

resulted in~temperature build-up in instrumentation cabinets. ;The elevated -j <WI

temperatures initiated several spurious solid state protection system alarms and

resulted in the'operators having to reduce output from both generating units.

This event is described in detail in IE Information Notice No. 85-89, "Potential

Loss of Solid State'Instrumentation Following Failure of Control Room Cooling."

On September 21, 1982, a similar event occurred at Davis-Besse Unit 1, and

involved the failure of a 48-volt power supply in the'-Steam aind'Feedwater Rupture

Control System (SFRCS). The failure of the power supply was attributed toiheat

buildup in the SFRCS cabinets. The licensee installed fans in the cabinets to

ensure more effective cooling.

This information notice requires no specific action or written response. If you

have any questions about the information in this notice,.please contact one of

the technical contacts listed below or the appropriate NRR project manager.

(hAarle E.Ros;s, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: C. Paulk, Region IV

(817) 860-8236 N. Fields, NRR

(301) 492-1173 Attachment: List of Recently Issued NRC Information Notices

Attachment 1 tIN89-30, Supplement 1 November 1, 1990

Page I of I

LIST OFRECENTLY ISSUED

- NRCINFORMATION NOTICES

uAte ot

Iotic1a No. Subhiect Issuance Issued to

90-69 Adequacy of Emergency And 10/31/90 All holders of OLs

Essential Lighting or CPs for nuclear

power reactors.

90-68 Stress Corrosion Cracking 10/30/90 All holders of OLs

of Reactor Coolant Pump Bolts or CPs for pres- surized water

reactors (PWRs).

90-67 Potential Security Equipment 10/29/90 All holders of OLs

Weaknesses or CPs for

nuclear power

reactors and

Category I fuel

facilities.

90-66 Incomplete Draining and 10/25/90 All holders of OLs

Drying of Shipping Casks for nuclear

power reactors

and all registered

users of XRC

approved waste

shipping packages.

8843. High Radiation Hazards 10/5/90 All holders of OLs

Supp. 1 From Irradiated Incoro or CPs for nuclear

Detectors and Cables power reactors.

90-65 Recent Orifice Plate 10/5/90 All holders of OLs

Problems or CPs for nuclear

power reactors.

90-64 Potential for Coaon-Mode 10/4/90 All holders of OLs

Failure Of High Pressure or CPs for pres- Safety Injection Pumps or surized-water

Release of Reactor Coolant reactors.

Outside Containment During

A ton-Of-Coolant Accident--

DI0* Operating License

CP* Construction Permit

UNITED STATES FRST CLASS MAKt

NUCLEAR REGULATORY COMMISSION POSTAGEI FEES PAIO

WASHINGTON. D.C. 20555 UItRC

. PRMIT N-. 0-7 OFFICIAL BUSINESS

PENALTY FOR PRIVATE USE. $300

IN 89-30, Supplement 1 November 1, 1990 than are water-to-water heat exchangers. However, an increase in service water

temperature in water-to-water heat exchangers may also result in the derating

of an EDG. The NRC is aware of other instances in which elevated ambient temp- eratures resulted in the failure or degradation of safety related components.

To avoid excessive cabinet temperatures and subsequent component failures, the

licensee for the Washington Nuclear Project, Unit 2, has instituted admin- istrative procedures to remove the doors from the static exciter voltage

regulator cabinet when the EDG room temperature exceeds 90 degrees F. The

licensee performed an analysis which concluded that internal temperatures in

the cabinets would exceed the long-term (greater than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />) thermal rating

of the cabinet components if the EDG room temperature were to exceed 90 degrees F.

Extended operation at or above this temperature would significantly increase the

probability of a component failure.

On December 16, 1985, the failure of a fan in an engineered safety features

(ESF) cabinet at Palo Verde Unit 1 resulted in the spurious actuation of several

ESF signals. These signals initiated the automatic start of the Train A EDG,

caused loads to be shed from the Train A vital bus, and initiated the operation

of the ESF load sequencer. The load shed signal did not clear, prohibiting the

automatic or manual sequencing of ESF electrical loads. The licensee installed

a control room alarm that annunciates on cabinet exit air high temperature.

On June 4, 1984, at the McGuire Station, a total loss of control area ventilation

resulted in temperature build-up in instrumentation cabinets. The elevated

temperatures initiated several spurious solid state protection system alarms and

resulted in the operators having to reduce output from both generating units.

This event is described in detail in IE Information Notice No. 85-89, "Potential

Loss of Solid State Instrumentation Following Failure of Control Room Cooling."

On September 21, 1982, a similar event occurred at Davis-Besse Unit 1, and

involved the failure of a 48-volt power supply in the Steam and Feedwater Rupture

Control System (SFRCS). The failure of the power supply was attributed to heat

buildup in the SFRCS cabinets. The licensee installed fans in the cabinets to

ensure more effective cooling.

This information notice requires no specific action or written response. If you

have any questions about the information in this notice, please contact one of

the technical contacts listed below or the appropriate NRR project manager.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: C. Paulk, Region IV

(817) 860-8236 N. Fields, NRR

(301) 492-1173 Attachment: List of Recently Issued NRC Information Notices

• See previous concurrence

OFC :NRR:EAB :REGION IV :TECH ED :SC/NRR/EAB :BC/NRR/EAB :BC/NRR/GC :DD/NRR/DOEA

_____ ------------ __ _ _ _______

__-______-____-____--

NAME :*EFIELDS  :*CPAULK  : * :DFISHER :ACHAFFEE :CBERLINGER

DATE ://90 0 / /90 /90  : /90 ://90

Document Name: 89-30, SUPP. 1 1

IN 8941', SUP 1 October XX, 1990 This information notice requires no specific action or written response. If you

have any questions about the information in this notice, please contact one of

the technical contacts listed below or the appropriate NRR project manager.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

C. Paulk, Region IV

(817) 860-8236- C

N. Fields, NRR

(301) 492-1173 Attachment: List of Recently Issued NRC Information Notices

• See previous concurrence

OFC :NRR:EAB :REGION IV :TECH ED :SSJCNRR/EAB :BCJNRR/EAB :tC "tC :DD/NRR/DOEA

_____: -- --------- ____________ ------ _ _ ------------ _____-__

NAME :*EFIELDS  :*CPAULK  : * :DFISHER :ACHAFFEE :CBERLINGER :CROSSI1 DATE:  :  :  : 1o1J71 I  :(D/P.Z/  : /T

Document Name: FTCALHOUN IN

To avoid excessive cabinet temperatures and subsequent component failures, the

licenfe for the Washington Nuclear Project, Unit 1, has instituted administrative

procedur to remove the doors from the static exciter voltage regulator cabinet

when the E room temperature exceeds 90 degrees F. The licensee performed an analysis

which conclu that internal temperatures in the cabinets would exceed the

long-term (grea than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />) thermal rating of the cabinet components if

the EDG room tempe ture were to exceed 90 degrees F. Extended operation at or

above this temperatu would significantly increase the probabilty of a component

failure.

On June 4, 1984, at the M ire Station, a total loss of control area ventilation

resulted in temperature bui -up in instrumentation cabinets. The elevated tempera- tures initiated several spur s solid state protection system alarms and resulted

in the operators having to redu output from both generating units. This event is

described in detail in IE Informa ion Notice No. 85-89, "Potential Loss of Solid

State Instrumentation Following Fai ure of Control Room Cooling."

On September 21, 1982, a similar event ccurred at Davis-Besse Unit 1, and involved

the failure of a 48-volt power supply in the Steam and Feedwater Rupture Control

System (SFRCS). The failure of the power upply was attributed to heat build-up in the

SFRCS cabinets. The licensee installed fa in the cabinets to ensure more

effective cooling.

On December 16, 1985, the failure of a fan in a engineered safety features (ESF)

cabinet at Palo Verde Unit 1 resulted in the spur ous actuation of several ESF

signals. These signals initiated the automatic st t of the Train A EDG, caused

loads to be shed from the Train A vital bus, and in iated the operation of

the ESF load sequencer. The load shed signal did not lear, prohibiting the

automatic or manual sequencing of ESF electrical loads The licensee installed

a control room alarm that annunciates on cabinet exit ai high temperature.

This information notice requires no specific action or wri ten response. If you

have any questions about the information in this notice, pl se contact one of

the technical contacts listed below or the appropriate NRR pr ect manager.

Charles E. Rossi, Director

Division of Operational Evens Assessment

Office of Nuclear Reactor Regulation

C. Paulk, Region IV

(817) 860-8236 N. Fields, NRR

(301) 492-1173 Attachment: List of Recently Issued NRC Information Notices

• See previous concurrence INA?9z d

OFC :NRR:EAB :REGION IV :TECH ED :SC R1t/EAB :BC/NRR/EAB :BC/NRR/GC :DD/NRR/DOEA

NAME :EFIELD :CPAULK  : * :DFISHER :ACHAFFEE :CBERLINGER :CROSSI

DATE * /:Y q '°/iq//c

OFFICIAL RECORD COPY

Document Name: FTCALHOUN IN

To avoid excessive cabinet temperatures and subsequent component failures, the

licensee for the Washington Nuclear Project Unit 1 has instituted administrative

procedures to remove the static ex-citer voltage regulator cabinet doors when the

EDG roo stemperature exceeds 90 degrees F. The licensee performed an analysis

which cont uded that internal temperatures in the cabinets would exceed the

long-term ( eater than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />), thermal rating of the cabinet components if

the EDG room mperature were to exceed 90 degrees F. Extended operation at

this temperatur or higher would significantly increase the probabilty that a

component failure ould occur.

On June 4, 1984, at t Mcquire Station, a total loss of control area ventilation

resulted in temperature uild-up in instrumentation cabinets. The elevated tempera- tures initiated several s rious solid state protection system alarms and resulted

in a operators having to re ce output from both generating units. This event is

described in detail in IE Inf mation Notice No. 85-89, "Potential Loss of Solid

State Instrumentation Following ailure of Control Room Cooling".

A similar event occurred at Davis- sse 1 on September 21, 1982 and involved the

failure of a 48-volt power supply in he Steam and Feedwater Rupture Control System

(SFRCS). The failure of the power sup y was attributed to heat build-up in the

SFRCS cabinets. The licensee installed ns in the cabinets to ensure more effective

cooling.

On December 16, 1985, the failure of a fan in n engineered safety features (ESF)

cabinet at Palo Verde Unit 1 resulted in the sp rious actuation of several ESF

signals. A spurious auto-start of the train A E , operation of the ESF load

sequencer, and a train A load shed signal. The lo d shed signal did not clear, prohibiting the automatic or manual sequencing of E electrical loads. The

licensee installed a control room alarm which annunci e on high cabinet exit

air temperature.

This information notice requires no specific action or wri en response. If you

have any questions about the information in this notice, ple se contact the

technical contact listed below or the appropriate NRR project anager.

Charles E. Rossi, Director

Division of Operational Events ssessment

Office of Nuclear Reactor Regul ion

C. Paulk, Region IV

(817) 860-8236 N. Fields, NRR

(301) 492-1173 Attachment: List of Recently Issued NRC Information Notices

OFC :NRR:EAB :REGION IV :TECH ED :SC/NRR/EAB :BC/NRR/EAB :BC/NRR/GC :DD/NRR/DOEA

NAME :NFIELDS :CPAULK  : TJH;;nI :DFISHER :ACHAFFEE :CBERLINGER :CROSSI

DATE :  :  : IOqJqo  :  :

OFFICIAL RECORD COPY

Document Name: FTCALHOUN IN