Information Notice 1990-02, Potential Degradation of Secondary Containment

Potential Degradation of Secondary Containment

ML031130355
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, 05000000, Zimmer, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant
Issue date:	01/22/1990
From:	Rossi C E Office of Nuclear Reactor Regulation
To:
References
IN-90-002, NUDOCS 9001160420
Download: ML031130355 (9)

I ft I i-UNITED STATES NUCLEAR REGULATORY

COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 January 22, 1990 NRC INFORMATION

NOTICE NO. 90-02: POTENTIAL

DEGRADATION

Addressees

All holders of operating

licenses or construction

permits for boiling water reactors (BWRs).

Purpose

This information

notice is intended to alert addressees

to potential

problems involving

degradation

of secondary

containment

as a result of unforeseen

inter-actions with various normal plant ventilation

systems and inadequate

surveillance

testing of secondary

containment

integrity.

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.Detcription

of Circumstances:

Duane Arnold Energy Center During a reactor building exhaust ventilation

inspection, an Iowa Electric system engineer discovered

a large hole in the duct work (see Figure 1).This hole allowed the main plant ventilation

system to communicate

directly with the reactor building ventilation

system, thus bypassing

the standby gas treatment

system (SGTS) and providing

a direct path for an untreated

release of radioactive

effluents

to the environment.

This pathway would have existed even with an automatic

Engineered

Safety Feature (ESF) isolation

of the reactor building ventilation

system and an autostart

of the SGTS. The licensee dis-covered that .its normal secondary

containment

integrity

surveillance

test (which requires a measurement

of 0.25 inch water vacuum with one train of SGTS operating)

was still apparently

satisfied

with the main plant ventilation

fans running. This has been the test configuration

used at the plant since initial startup in 1974. However, upon conducting

the test with the SGTS operating

as designed and the main plant ventilation

secured, the 0.25-inch vacuum could not be achieved because of numerous secondary

containment

leaks.A 10 CFR 50.72 4-hour notification

was made to the NRC upon this discovery.

The licensee determined

that during the performance

of the secondary

contain-ment integrity

surveillance

as it was previously

conducted, the main plant 9001160420

Zjl_ _v c

IN 90-02 January 22, 1990 ventilation, turbine building ventilation, and the radwaste building ventila-tion exhaust fans had aided the SGTS in drawing the required vacuum. Because surveillance

tests performed

since initial unit startup usually indicated

that the required negative pressure had been obtained, numerous secondary

contain-ment integrity

deficiencies

went undetected

and uncorrected.

The maintenance

to correct this overall degradation

of the secondary

containment

required more than 3 weeks of effort to locate and repair numerous door seals, electrical

penetrations, steam tunnel boot seals, dampers, building seals, and duct systems.These repairs resulted in an improvement

in the measured secondary

containment

vacuum from less than 0.08 inch of water to greater than 0.25 inch of water, as determined

by retesting

with a new surveillance

test procedure.

This test now requires all major plant exhaust ventilation

fans that potentially

communicate

with secondary

containment

to be secured.Continued

testing after repairs has shown that one main plant exhaust ventilation

fan can still draw an approximate

500 to 1000 standard cubic feet-per-minute (SCFM)volume' from the reactor building ventilation

system (the secondary

containment

boundary)

when the ESF-required

isolation

is in effect. As this circumstance

could result in an untreated

ground-level

release under certain accident scenarios, the licensee developed

alarm response procedures

designed to secure the main plant ventilation

fans when secondary

containment

isolation

is initiated

and main plant exhaust ventilation

radiation

monitors reach specified

values. Iowa Electric is also considering

long-term

corrective

action involving

hardware modifications

that would prevent main plant ventilation

from drawing air out of the reactor building under accident conditions.

Monticello

As a result of the secondary

containment

deficiencies

identified

at Duane Arnold, the NRC resident inspector

contacted

the licensee for the Monticello

plant con-cerning the procedures

and practices

for testing the secondary

containment

system.The licensee had normally tested the secondary

containment

integrity

with the main plant exhaust fans running and isolated both supply and exhaust fans in the reactor building.

However, on October 14, 1989, the licensee conducted the secondary

containment

integrity

test with the main plant exhaust fans secured and was not able to maintain the 0.25-inch

water vacuum required by the technical

specifications.

The vacuum reached in the reactor building was only 0.1 inch of water. Preliminary

investigation

revealed that failure of the test was due to leaks in the reactor building supply and exhaust system dampers and various other secondary

containment

leaks. The licensee also believes that the operation

of the main plant exhaust fans assisted the SGTS in drawing the required vacuum on the secondary

containment, thus establishing

a path that bypassed the SGTS. A 10 CFR 50.72 notification

was made to the NRC.Discussion

of Safety Significance:

Plant heating, ventilation, and air conditioning (HVAC) systems are diverse among boiling water reactors.

Interactions

between these systems and the standby gas treatment

system could mask degradation

of the secondary

contain-ment boundary during surveillance

testing and could exacerbate

such degradatiof+t'

by diverting

flow from the SGTS following

an accident.

-

K>IN 90-02 January 22, 1990 For those plants discussed

above, a portion of the secondary

containment

boundary is formed by the ductwork and isolation

dampers of the reactor build-ing ventilation

system. This system exhausts to a common plenum area within the reactor building, but outside secondary

containment, where ventilation

flows from other plant HVAC systems are also directed.

The high-capacity

main plant ventilation

exhaust fans take suction from the plenum area and discharge the flow through the reactor building roof stacks. Because of the high capa-city of the main plant exhaust fans and their proximity

to the reactor building ventilation

system components

that form part of the secondary

containment

boundary, the potential

exists for air flow to bypass the SGTS even when the secondary

containment

is isolated.

Further, if the main plant ventilation

fans are operated during surveillance

testing, degradation

of secondary

containment

could go undetected

as the main plant fans and the SGTS fans could collectively

draw the required vacuum.In view of the possibility

of the main plant ventilation

systems masking deficiencies

in SGTS and/or secondary

containment

integrity

and of creating possible untreated

release paths under accident conditions, licensees

for other BWR plants may wish to review the design and operation

of major plant ventila-tion systems and to review their secondary

containment

integrity

surveillance

procedures.

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:

William L. Axelson, Region III (708) 790-5574 John A. Kudrick, NRR (301) 492-0871 James R. Hall, NRR (301) 492-1391 Attachments:

1. Figure 1 -Reactor Building Ventilation

2. List of Recently Issued NRC Information

Notices

Attachment

1 IN 90-02 January 22, 1990 Failed DucUng Isolatlon

Dampers Reactor Buiding VentShaft Fgure 1 Reactor Building Ventilation

Iw/I1-89 A1087 K>Attachment

2 IN 90-02 January 22, 1990 ti e.-..11 -1..,-1-LIST OF RECENTLY ISSUED NRC INFORMATION

NOTICES Information

Date of Notice No. Subject Issuance Issued to 90-01 89-90 89-89 89-88 89-87 89-45, Supp. 2 89-86 89-85 89-84 Importance

of Proper Response to Self-Identified

Violations

by Licensees Pressurizer

Safety Valve Lift Setpoint Shift Event Notification

Worksheets

Recent NRC-Sponsored

Testing of Motor-Operated

Valves Disabling

of Emergency Diesel Generators

by Their Neutral Ground-Fault

Protection

Circuitry Metalclad, Low-Voltage

Power Circuit Breakers Refurbished

with Substandard

Parts Type HK Circuit Breakers Missing Close Latch Anti-Shock Springs.EPA's Interim Final Rule on Medical Waste Tracking and Management

Failure of Ingersoll

Rand Air Start Motors as a Result of Pinion Gear Assembly Fitting Problems 1/12/90 12/28/89 12/26/89 12/26/89 12/19/89 12/15/89 12/15/89 12/15/89 12/12/89 All holders of NRC materials

licenses.All holders of OLs or CPs for PWRs.All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for nuclear power reactors.All medical, academic, industrial, waste broker, and waste disposal site licensees.

All holders of OLs or CPs for nuclear power reactors.OL = Operating

License CP = Construction

Permit

IN 90-02 January 22, 1990 For those plants discussed

above, a portion of the secondary

containment

boundary is formed by the ductwork and isolation

dampers of the reactor build-ing ventilation

system. This system exhausts to a common plenum area within the reactor building, but outside secondary

containment, where ventilation

flows from other plant HVAC systems are also directed.

The high-capacity

main plant ventilation

exhaust fans take suction from the plenum area and discharge the flow through the reactor building roof stacks. Because of the high capa-city of the main plant exhaust fans and their proximity

to the reactor building ventilation

system components

that form part of the secondary

containment

boundary, the potential

exists for air flow to bypass the SGTS even when the secondary

containment

is Isolated.

Further, if the main plant ventilation

fans are operated during surveillance

testing, degradation

of secondary

containment

could go undetected

as the main plant fans and the SGTS fans could collectively

draw the required vacuum.In view of the possibility

of the main plant ventilation

systems masking deficiencies

in SGTS and/or secondary

containment

integrity

and of creating possible untreated

release paths under accident conditions, licensees

for other BWR plants may wish to review the design and operation

of major plant ventila-tion systems and to review their secondary

containment

integrity

surveillance

procedures.

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:

William L. Axelson, Region III (708) 790-5574 John A. Kudrick, NRR (301) 492-0871 James R. Hall, NRR (301) 492-1391 Attachments:

1. Figure 1 -Reactor Building Ventilation

2. List of Recently Issued NRC Information

Notices Document Name: INFO NOTICE -JACKIW, KIESSEL*SEE PREVIOUS CONCURRENCES

D *C/OGCB:DOEA:NRR

• RPB:ARM *D/DST:NRR

E CHBerlinger

TechEd AThadani 01//190 01/10/90 12/21/89 12/18/89*OGCB:DOEA:NRR*RIII

• PD33:DRSP:NRR

• SPLB:DST:NRR*C/SPLB:DST:NRR

RJKiessel

EGGreenman

JRHall JKudrick CEMcCracken

11/16/89 11/21/89 11/16/89 12/12/89 12/12/89 IN 90-XX January xx, 1990 For those plants discussed

above, a portion of the secondary

containment

boundary is formed by the ductwork and isolation

dampers of the reactor build-ing ventilation

system. This system exhausts to a common plenum area within the reactor building, but outside secondary

containment, where ventilation

flows from other plant HVAC systems are also directed.

The high-capacity

main plant ventilation

exhaust fans take suction from the plenum area and discharge the flow through the reactor building roof stacks. Because of the high capa-city of the main plant exhaust fans and their proximity

to the reactor building ventilation

system components

that form part of the secondary

containment

boundary, the potential

exists for air flow to bypass the SGTS even when the secondary

containment

is isolated.

Further, if the main plant ventilation

fans are operated during surveillance

testing, degradation

of secondary

containment

could go undetected

as the main plant fans and the SGTS fans could collectively

draw the required vacuum.In view of the possibility

of the main plant ventilation

systems' masking deficiencies

in SGTS and/or secondary

containment

integrity

and of creating possible untreated

release paths under accident conditions, licensees

for other BWR plants may wish to review the design and operation

of major plant ventila-tion systems and to review their secondary

containment

integrity

surveillance

procedures.

This information

notice requires no specific action or written response.

If you have any questions

about the information

in this notice, please contact 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:

William L. Axelson, Region III (708) 790-5574 John A. Kudrick, NRR (301) 492-0871 James R. Hall, NRR (301) 492-1391 Attachments:

1. Figure 1 -Reactor Building Ventilation

2. Figure 2 -Exhaust Fan Room 3. List of Recently Issued NRC Information

Notices Document Name: INFO NOTICE -JACKIW, KIESSEL*SEE PREVIOUS CONCURRENCES

D/DOEA:NRR

C/OGCB:D C Byt;*RPB:ARM

• D/DST:NRR

CERossi CHBerline

j) TechEd AThadani 01/ /90 01/Y,/90-

' 12/21/89 12/18/89*OGCB:DOEA:NRR*RIII

• PD33:DRSP:NRR

• SPLB:DST:NRR*C/SPLB:DST:NRR

RJKiessel

EGGreenman

JRHall -lf JKudrick CEMcCracken

11 11/21 11/16/8w 12/12/89 12/12/89 441/44s~4 IN 89-XX%2 ~November

xx, 1989 standby gas treatment

system could mask degradation

of the secondary

contain-ment boundary during surveillance

testing and could exacerbate

such degradation

by diverting

flow from the SGTS following

an accident.For those plants discussed

above, a portion of the secondary

containment

boundary is formed by the ductwork and isolation

dampers of the reactor build-ing ventilation

system. This system exhausts to a common plenum area within the reactor building, but outside secondary

containment, where ventilation

flows from other plant HVAC systems are also directed.

The high capacity main plant ventilation

exhaust fans take suction from the plenum area and discharge the flow out through the reactor building roof stacks. Due to the high capa-city of the main plant exhaust fans and their proximity

to the reactor building ventilation

system components

that form part of the secondary

containment

boundary, the potential

exists for air flow to bypass the SGTS even when the secondary

containment

is isolated.

Further, if the main plant ventilation

fans are operated during surveillance

testing, degradation

of secondary

containment

could go undetected

as the main plant fans and SGTS fans could collectively

draw the required vacuum.In view of the possibility

of main plant ventilation

systems masking deficien-cies in SGTS and/or secondary

containment

integrity

and of creating possible untreated

release paths under accident conditions, other BWR plants may wish to review the design and operation

of major plant ventilation

systems and to review their secondary

containment

integrity

surveillance

procedures.

This information

notice requires no specific action or written response.

If you have any questions

about the information

in this notice, please contact 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: William L. Axelson, Region III (708) 790-5574 John A. Kudrick, NRR (301) 492-0871 James R. Hall, NRR (301) 492-1391 Attachments:

1. Figure 1 -Reactor Building Ventilation

2. Figure 2 -Exhaust Fan Room 3. List of Recently Issued NRC Information

Notices Document Name: INFO NOTICE -JACKIW, KIESSEL*SEE PREVIOUS CONCURRENCES

sit D/DOEA:NRR

C/OGCB:DOEA:NRR

RPB:ARO'CERossi CHBerlinger

TechEd 11/ /89 11/ /89 ftH/.Zf/*OGCB:DOEA:NRR*RIII

• PD33:DRSP:NRR

SPLB: R RJKiessel

EGGreenman

JRHall *udri 11/16/89 11/21/89 11/16/89 WMI Al'D/DST:NRR ni MAK /89 C/SPLB:DST:

WG9 CEMcCracken,_

--/d 89