Information Notice 1992-33, Increased Instrument Response Time When Pressure Dampening Devices Are Installed

Increased Instrument Response Time When Pressure Dampening Devices Are Installed
	ML031200378
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:	04/30/1992
From:	Rossi C; Office of Nuclear Reactor Regulation
To:	;
References
	IN-92-033, NUDOCS 9204240146
	Download: ML031200378 (9)
	v • d • e

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 April 30, 1992 NRC INFORMATION NOTICE 92-33: INCREASED INSTRUMENT RESPONSE TIME WHEN

PRESSURE DAMPENING DEVICES ARE INSTALLED

Addressees

All holders of operating licenses or construction permits for nuclear power

reactors.

Purpose

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

to alert addressees to increased response times for pressure sensing instruments

that occur when pressure dampening devices are installed in the instrument for

sensing lines. It is expected that recipients will review the information

applicability to their facilities and consider actions, as appropriate, to

avoid similar problems. However, suggestions contained in this information

notice are not NRC requirements; therefore, no specific action or written

response is required.

Description of Circumstances

On September 25, 1991, the GPU Nuclear Corporation, licensee for the Oyster

Creek Nuclear Generating Station, initiated a plant shutdown after determining

that seven of eight isolation condenser line break pressure sensors did not

meet the plant technical specification requirements for instrument response

times. The licensee's trouble shooting determined that pressure dampening

devices in the sensing lines for these differential pressure sensors had caused

an increase in the response times. Furthermore, the licensee found that the

time delay caused by these devices is significant at both low and high pressures.

Discussion

The pressure dampening devices (snubbers) which utilize sintered stainless

dampen

steel elements are generally installed in instrument sensing lines to contami- pressure oscillations or to protect the instruments from particulate

nation.

When the sensors failed to meet the required response times during surveillance

tests, the licensee reviewed the pressure sensing system and found that the

snubbers were causing unacceptable time delays. The licensee later removed the

snubbers because they are not needed when using the upgraded Barton pressure

sensors that were installed.

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IN 92-33 April 30, 1992 Snubber time delay will not be detected in response time testing

directly at the sensing instrument (see Figure 1.) The effect of conducted

will differ from sensor to sensor because of differences in the a snubber

volumetric

displacement of fluid within the pressure sensing mechanisms. System

time can also be degraded by the accumulation of foreign material response

line snubbers. in sensing

The NRC's Office of Nuclear Regulatory Research is conducting a

on the performance of pressure instrumentation at nuclear power generic study

staff plans to publish the results in NUREG/CR 5851, "Long Term plants. The

and Aging Characteristics of Nuclear Plant Pressure Transmitters." Performance

has completed a part of this effort, and the results of tests conducted The staff

pressure sensor response time testing were published in an ISA (Instrument on

Society of America) transaction 91-720, "Response Time Testing of

Transmitters in Nuclear Power Plants." This publication addresses Pressure

causes for delays in sensor response and documents that significant various

delays can occur. time

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.

harles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical contacts: Thomas Koshy, NRR

(301) 504-1176 Iqbal Ahmed, NRR

(301) 504-3252 Attachments:

1. Figure 1. Test Configuration that Excludes the

Effect of Snubbers

2. List of Recently Issued NRC Information Notices

Attachment 1 IN 92-33 April 30, 1992 PRESSURE SENSING DEVICE

UBBERS

Ti LOW SIDE BLOCK VALVE

TO PROCESS

CONNECTION

Figure 1.

Test Configuration That Excludes the Effect of Snubbers

2 a

m C/) Attachment 2 z IN 92-33 cn April 30, 1992 LIST OF RECENTLY ISSUED

- C1 NRC INFORMATION NOTICES

D

>cn Information

0 F)

Date of

mZ Notice No. Subject Issuance Issued to

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~03 *o m

A L

mM 92-32 Problems Identified with 04/29/92 All holders of OL or CPs

Emergency Ventilation for nuclear power reactors.

Systems for Near-Site

(

(An (Within 10 Miles) Emer- U). gency Operations Facili- ties and Technical Support

2 Centers

92-31 Electrical Connection 04/27/92 All holders of OLs or CPs

Problem in Johnson for nuclear power reactors.

Yokogawa Corporation

YS-80 Programmable Indi- cating Controllers

92-30 Falsification of Plant 04/23/92 All holders of OLs or CPs

Records for nuclear power reactors

and all licensed operators

and senior operators.

92-21, Spent Fuel Pool Re- 04/22/92 All holders of OLs or CPs

Supp. I activity Calculations for nuclear power reactors.

92-29 Potential Breaker His- 04/17/92 All holders of OLs or CPs

coordination Caused by for nuclear power reactors.

Instantaneous Trip

Circuitry

92-28 - Inadequate Fire Suppres- 04/08/92 All holders of OLs or CPs

sian System Testing for nuclear power reactors.

92-27 Thermally Induced Acceler- 04/03/92 All holders of OLs or CPs (.

ated Aging and Failure of for nuclear power reactors.

ITE/GOULD A.C. Relays Used

in Safety-Related Applic-

0 ations

0

,,

92-26 Pressure Locking of Motor- 04/02/92 All holders of OLs or CPs

Operated Flexible Wedge for nuclear power reactors.

Gate Valves

'Im 00

rn ->

OL = Operating License

CA C? - Construction Permit

< \

IN 92-33 April 30, 1992 Snubber time delay will not be detected in response time testing conducted

directly at the sensing instrument (see Figure 1.) The effect of a snubber

will differ from sensor to sensor because of differences in the volumetric

displacement of fluid within the pressure sensing mechanisms. System response

time can also be degraded by the accumulation of foreign material in sensing

line snubbers.

The NRC's Office of Nuclear Regulatory Research is conducting a generic study

on the performance of pressure instrumentation at nuclear power plants. The

staff plans to publish the results in NUREG/CR 5851, "Long Term Performance

and Aging Characteristics of Nuclear Plant Pressure Transmitters." The staff

has completed a part of this effort, and the results of tests conducted on

pressure sensor response time testing were published in an ISA (Instrument

Society of America) transaction 91-720, "Response Time Testing of Pressure

Transmitters in Nuclear Power Plants." This publication addresses various

causes for delays in sensor response and documents that significant time

delays can occur.

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. Orginal Signed by

Charles E. Rossi

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical contacts: Thomas Koshy, NRR

(301) 504-1176 Iqbal Ahmed, NRR

(301) 504-3252 Attachments:

1. Figure 1. Test Configuration that Excludes the

Effect of Snubbers

2. List of Recently Issued NRC Information Notices

Reviewed by J. Main, Technical Editor, on 02/07/92

SEE PREVIOUS CONCURRENCE

OFC :OEAB:DOEA :SICB:DST :SC:OEAB:DOEA:C:SICB:DST :C:OEAB:DOEA :C:OGCB:DOEA :D:DOEA

NAME :TKoshy* :IAhmed* :DFischer* :SNewberry* :AChaffee* :CBerlinger*

_____ --------------

__ _ - -:-- - -- - - ------ :-- - -- - - : -- - - - - -\-- - - - - - - -

DATE :02/12/92 :03/03/92 : 03/06/92 :03/18/92 :03/19/92 :04/20/92 :04/ v 92 OFFICIAL RECORD COPY

Document Name: IN 92-33

IN 92-XX

April xx, 1992 Since the snubbers are mounted upstream of the sensors, this time delay will

not be experienced in response time testing conducted directly at the sensing

instrument (see Figure 1.) These snubbers could degrade and reduce the flow

through the device, further increasing the time delay. The effect of a snubber

would differ between various sensors because of the differences in the volumetric

displacement of fluid within their pressure sensing mechanism. System response

time could be degraded by the presence and condition of snubbers in the sensing

line.

The NRC's Office of Nuclear Regulatory Research is conducting a generic study

on the performance of pressure instrumentation at nuclear power plants. The

staff plans to publish this study report as NUREG/CR 5851, "Long Term Performance

and Aging Characteristics of Nuclear Plant Pressure Transmitters." The staff

completed a part of this effort and the result of tests conducted on pressure

sensor response time testing was published in an ISA (Instrument Society of

America) transaction 91-720, "Response Time Testing of Pressure Transmitters in

Nuclear Power Plants." This publication addresses various causes for the

delays in sensor response and documents that significant time delays can occur.

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.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical contacts: Thomas Koshy, NRR

(301) 504-1176 Iqbal Ahmed, NRR

(301) 504-3252 Attachments:

1. Figure 1. Test Configuration that Excludes the

Effect of Snubbers

2. List of Recently Issued NRC Information Notices

Reviewed by J. Main, Technical Editor, on 02/07/92

SEE PREVIOUS CONCURRENCE

,OFC :OEAB:DOEA :SICB:DST :SC:OEAB:DOEA:C:SICB:DST :C:OEAB:DOEA :C:OA D:DOEA

NAME :TKoshy* :IAhmed* :DFischer* :SNewberry* :AChaffee* :CB lnger :CRossi -

DATE :02/12/92 :03/03/92 : 03/06/92 :03/18/92 :03/19/92 : 9/A5/ 92 : / /92 OFFICIAL RECORD COPY

Document Name: IN/KOSHY

IN 92-XX

March xx, 1992 Since the snubbers are mounted upstream of the sensors, this time delay will

not be experienced in response time testing conducted directly at the sensing

instrument. These snubbers could degrade and reduce the flow through the

device, further increasing the time delay. The effect of a snubber would

differ between various sensors because of the differences in the volumetric