Information Notice 1996-13, Potential Containment Leak Paths Through Hydrogen Analysis

Potential Containment Leak Paths Through Hydrogen Analysis

ML031060240
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:	02/26/1996
From:	Crutchfield D Office of Nuclear Reactor Regulation
To:
References
IN-96-013, NUDOCS 9602220234
Download: ML031060240 (7)

I

UNITED STATES

NUCLEAR REGULATORY COMMISSION K

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, DC 20555-0001 February 26, 1996 NRC INFORMATION NOTICE 96-13: POTENTIAL CONTAINMENT LEAK PATHS THROUGH

HYDROGEN ANALYZERS

Addressees

nuclear power

All holders of operating licenses or construction permits for

reactors.

Purpose

information

The U.S. Nuclear Regulatory Commission (NRC) is issuing this through

notice to alert addressees to potential containment leak paths

review the information

hydrogen analyzers. It is expected that recipients will as appropriate, to

for applicability to their facilities and consider actions, this information

avoid similar problems. However, suggestions contained in

or written

notice are not NRC requirements; therefore, no specific action

response is required.

Description of Circumstances

determined

On September 13, 1995, the licensee for Catawba Nuclear Station analyzer panel

that leakage from an internal component in a Unit 1 hydrogen

specified in the technical

exceeded the containment bypass leakage limits other

specifications (TS). Testing, performed in response to several showed that

containment integrity concerns with the hydrogen analyzer systems, pump shaft seal on a sample

the source of the bypass leakage was a defective building.

pump located inside the hydrogen analyzer cabinet in the auxiliary

unit at Catawba

Two redundant hydrogen analyzer systems are installed at each inside the

to provide continuous indication of hydrogen concentration

The analyzer panels are Teledyne

containment after a design-basis accident. adjacent to

Analytical Instruments and are located in the auxiliary building

system is connected to the

the containment. Each hydrogen analyzer the sample

containment atmosphere with inlet instrument tubing that draws which the sample

stream to the analyzer panel and with outlet tubing through

atmosphere. The inlet and outlet tubing

stream is returned to the containment valves in

by two containment isolation

is isolated at the containment boundary isolation

series on each line that do not receive an automatic containment consist of

signal. The internal components of the analyzer panel also

displacement pump, and an analysis volume.

isolation valves, a small positive on the inlet and

In standby conditions, containment isolation valves located

deenergized with

outlet lines are normally closed and the hydrogen analyzer is After an

the internal isolation valves closed and the sample pump off. valves to

accident, emergency procedures direct the inlet and outlet isolation begin sampling

be opened and the hydrogen analyzer panel to be energized to

9 2L- S'/7 ou e q70 -1t- (

9602220234 fort /sy a d I1 Ao

IN 96-13 February 26, 1996 the containment atmosphere. When the hydrogen analyzer panel is energized, the internal isolation valves open and the sample pump starts.

The licensee did not recognize during the development of the local leak rate

test and post-maintenance test procedures for the hydrogen analyzer

penetrations that the hydrogen analyzer panel was required to be energized and

its sample pump disabled to fully test the system as a containment boundary.

Failure to energize the panel during leak rate testing results in an

incomplete containment boundary configuration and can allow an undetected

potential containment bypass path to exist. The licensee analysis of the

potential dose consequences of the hydrogen analyzer containment bypass as- found leakage showed that the calculated control room operator exposure from a

design basis accident would not exceed the criteria of General Design

Criterion 19 of Appendix A to Part 50 of Title 10 of the Code of Federal

Regulations (10 CFR) and calculated offsite exposures from a design basis

accident would not exceed the exposure guidelines of 10 CFR Part 100.

The licensee also identified a containment integrity concern associated with

the periodic calibration testing of the hydrogen analyzers. The licensee

recognized that calibration testing allows a vent path from the containment

into the analyzer that was not Type C tested and would not automatically

isolate during a design-basis accident.

On November 9, 1994, the licensee for Braidwood Station, Unit 2, completed a

containment integrated leak rate test. For this test, the 1/4-inch nominal

containment penetration hydrogen sensing lines for both trains were

disconnected outboard of the closed containment isolation valves, and a

balloon was placed on the end of each line to identify any leakage. The

procedure did not specify whether to disconnect the sensing line inside the

hydrogen monitor cabinet or outside. The operators who lined up the test

disconnected the lines inside the cabinet. The licensee's investigation

concluded that when other operators restored the system after the test, they

observed the exterior sensing lines and assumed that the lines had been

reconnected. Therefore, the sensing lines remained disconnected inside the

cabinet. On January 31, 1995, the operations department wrote a problem

identification report to identify a growing difference in the hydrogen

readings on the A and B trains that are taken every shift. On February 15,

1995, during troubleshooting, the A train lines were found to be disconnected, approximately 3 months after they were disconnected.

The hydrogen monitors at Braidwood are normally isolated. However, during a

loss-of-coolant accident, the emergency operating procedures direct the

operators to put them in service to monitor containment hydrogen

concentration. This would create an unfiltered release path from the

containment to the auxiliary building. The licensee calculated that

regulatory limits would be exceeded within 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> if both monitors were

disconnected and within 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> if only one monitor were disconnected. Area

radiation monitors near the hydrogen monitors and radiation monitors in the

auxiliary building exhaust would assist the operators in identifying the leak.

IN 96-13 February 26, 1996 Discussion

and equipment that will be exposed

Because containment penetrations, systems, rate tested to ensure that

to the containment atmosphere must be leaka design-basis accident, the

containment integrity is maintained after consider the penetration

procedures for these tests must adequately monitor containment isolation

configuration. Additionally, because hydrogen

after a design-basis accident, any

valves are normally procedurally opened may bypass the containment and can

leakage in the hydrogen monitor system guidelines.

challenge regulatory radiological exposure

action or written response. If

This information notice requires no specific in this notice, please contact

you have any questions about the informationor the appropriate Office of

one of the technical contacts listed below

Nuclear Reactor Regulation project manager.

De .Crutch eld irector

Division of Reactor P-ogram Management

Office of Nuclear Reactor Regulation

Technical Contacts: Peter Balmain, Region II

(803) 831-2963 Internet: pabl@nrc.gov

James Pulsipher, NRR

(301) 415-2811 Internet: jcp2@nrc.gov

John R. Tappert, NRR

(301) 415-1167 Internet: jrt4nrc.gov

Attachment: List of Recently Issued NRC Information Notices

Attachment

IN 96-13 February 26, 1996 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information Date of

Subject Issuance Issued to

Notice No.

Control Rod Insertion 02/15/96 All holders of OLs or CPs

96-12 for nuclear power reactors

Problems

Ingress of Demineralizer 02/14/96 All holders of OLs or CPs

96-11 for pressurized water

Resins Increases Potential

Stress Corrosion Cracking nuclear power reactors

of Control Rod Drive

Mechanism Penetrations

Potential Blockage by 02/13/96 All holders of OLs or CPs

96-10 for nuclear power reactors

Debris of Safety System

Piping Which is Not Used

During Normal Operation

or Tested During Surveil- lances

Damage in Foreign Steam 02/12/96 All holders of OLs or CPs

96-09 for pressurized water

Generator Internals

reactors

Thermally Induced Pres- 02/05/96 All holders of OLs or CPs

96-08 for nuclear power reactors

sure Locking of a High

Pressure Coolant Injec- tion Gate Valve

Slow Five Percent Scram 01/26/96 All holders of OLs or CPs

96-07 for boiling water reactors

Insertion Times Caused

By Viton Diaphragms in

Scram Solenoid Pilot

Valves

Design and Testing 01/25/96 All holders of OLs or CPs

96-06 for nuclear power reactors

Deficiencies of Tornado

Dampers at Nuclear Power

Plants

Partial Bypass of Shutdown 01/18/96 All holders of OLs or CPs

96-05 for boiling water reactors

Cooling Flow from the

Reactor Vessel

OL = Operating License

CP - Construction Permit

IN 96-13 February 26, 1996 Discussion

Because containment penetrations, systems, and equipment that will be exposed

to the containment atmosphere must be leak rate tested to ensure that

containment integrity is maintained after a design-basis accident, the

procedures for these tests must adequately consider the penetration

configuration. Additionally, because hydrogen monitor containment isolation

valves are normally procedurally opened after a design-basis accident, any

leakage in the hydrogen monitor system may bypass the containment and can

challenge regulatory radiological exposure guidelines.

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 Office of

Nuclear Reactor Regulation project manager.

original signed by

Dennis M. Crutchfield, Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical Contacts: Peter Balmain, Region II

(803) 831-2963 Internet: pabl@nrc.gov

James Pulsipher, NRR

(301) 415-2811 Internet: jcp2@nrc.gov

John R. Tappert, NRR

(301) 415-1167 Internet: jrt@nrc.gov

Attachment: List of Recently Issued NRC Information Notices

Tech Editor Reviewed 12/11/95

• see previous concurrence

OFFICE C/SCSB:DSSA C/PECB:DRPM D/Dn

-NE CBerlinger * AChaffee * DArKfield

DATE 12/21/95 1/25/96 -1-/26/96 Official Record Copy

DOCUMENT NAME: S:\DRPM SEC\96-13.IN

IN 96-XX

January XX, 1995 Discussion

Because containment penetrations, systems, and equipment that will be exposed

to the containment atmosphere must be leak rate tested to ensure that

containment integrity is maintained after a design-basis accident, the

procedures for these tests must adequately consider the penetration

configuration. Additionally, because hydrogen monitor containment isolation

valves are normally procedurally opened after a design-basis accident, any

leakage in the hydrogen monitor system may bypass the containment and can

challenge regulatory radiological limits.

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 Office of

Nuclear Reactor Regulation (NRR) project manager.

Dennis M. Crutchfield, Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical Contacts: Peter Balmain, Region II

(803) 831-2963 ----

E Mail: A NOV

James Pulsipher, NRR (

(301) 415-2U L_

E Mail: CP2@NRC.GDY,

John R. Tappert, NRR

(301) 415-1167- E Mail: TNRC.

Attachment: List of Recently Issued NRC Information Notices

Tech Editor Reviewed 12/11/95

• see previous concurrence

OFFICE C/SCSB:DSSA C/PECB:DRPM D/DRPM

.NME CBerlinger LrAChaffee

• 3l DCrutchfield

DATE 12/21/95 /25/196

• 1 / /96 L. )

Official Record Copy ZWA"L_1'

DOCUMENT NAME: G:\JRT\H2LEAK.IN

\-

IN 95-XX

December XX, 1995 Discussion

Because containment penetrations, systems, and equipment that will be exposed

to the containment atmosphere must be leak rate tested to ensure that

containment integrity is maintained after a design-basis accident, the

procedures for these tests must adequately consider the penetration

configuration. Additionally, because hydrogen monitor containment isolation

valves are normally procedurally opened after a design-basis accident, any

leakage in the hydrogen monitor system may bypass the containment and can

challenge regulatory radiological limits.

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 Office of

Nuclear Reactor Regulation (NRR) project manager.

Dennis M. Crutchfield, Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical Contacts: Peter Balmain, Region II

(803) 831-2963 E Mail: PAB1@NRC.GOV

James Pulsipher, NRR

(301) 415-2811 E Mail: JCP2@NRC.GOV

John R. Tappert, NRR

(301) 415-1167 E Mail: JRT@NRC.GOV

Attachment- Li of Recently Issued NRC Information Notices

OFFICE C/SCSB:DSSA C/PECB:DRPM D/DRPM

KME CBerlinger AChaffee DCrutchfield

DATE 11./2J/95 &,2) / /95 / /95 ji

DOCUMENT NAME: G:\JRT\H2LEAK.IN