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, 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
Revision:	0
From:	Rossi C E Office of Nuclear Reactor Regulation
To:
References
IN-92-033, NUDOCS 9204240146
Download: ML031200378 (9)

UNITED STATESNUCLEAR REGULATORY COMMISSIONOFFICE OF NUCLEAR REACTOR REGULATIONWASHINGTON, D.C. 20555April 30, 1992NRC INFORMATION NOTICE 92-33:INCREASED INSTRUMENT RESPONSE TIME WHENPRESSURE DAMPENING DEVICES ARE INSTALLED

Addressees

All holders of operating licenses or construction permits for nuclear powerreactors.

Purpose

The U.S. Nuclear Regulatory Commission (NRC) is issuing this information noticeto alert addressees to increased response times for pressure sensing instrumentsthat occur when pressure dampening devices are installed in the instrumentsensing lines. It is expected that recipients will review the information forapplicability to their facilities and consider actions, as appropriate, toavoid similar problems. However, suggestions contained in this informationnotice are not NRC requirements; therefore, no specific action or writtenresponse is required.

Description of Circumstances

On September 25, 1991, the GPU Nuclear Corporation, licensee for the OysterCreek Nuclear Generating Station, initiated a plant shutdown after determiningthat seven of eight isolation condenser line break pressure sensors did notmeet the plant technical specification requirements for instrument responsetimes. The licensee's trouble shooting determined that pressure dampeningdevices in the sensing lines for these differential pressure sensors had causedan increase in the response times. Furthermore, the licensee found that thetime delay caused by these devices is significant at both low and high pressures.DiscussionThe pressure dampening devices (snubbers) which utilize sintered stainlesssteel elements are generally installed in instrument sensing lines to dampenpressure oscillations or to protect the instruments from particulate contami-nation.When the sensors failed to meet the required response times during surveillancetests, the licensee reviewed the pressure sensing system and found that thesnubbers were causing unacceptable time delays. The licensee later removed thesnubbers because they are not needed when using the upgraded Barton pressuresensors that were installed.9204 /X 4A= I {e0(q Q-/ /~ A3/4-//C(

IIN 92-33April 30, 1992 Snubber time delay will not be detected in response time testing conducteddirectly at the sensing instrument (see Figure 1.) The effect of a snubberwill differ from sensor to sensor because of differences in the volumetricdisplacement of fluid within the pressure sensing mechanisms. System responsetime can also be degraded by the accumulation of foreign material in sensingline snubbers.The NRC's Office of Nuclear Regulatory Research is conducting a generic studyon the performance of pressure instrumentation at nuclear power plants. Thestaff plans to publish the results in NUREG/CR 5851, "Long Term Performanceand Aging Characteristics of Nuclear Plant Pressure Transmitters." The staffhas completed a part of this effort, and the results of tests conducted onpressure sensor response time testing were published in an ISA (InstrumentSociety of America) transaction 91-720, "Response Time Testing of PressureTransmitters in Nuclear Power Plants." This publication addresses variouscauses for delays in sensor response and documents that significant timedelays can occur.This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contact oneof the technical contacts listed below or the appropriate Office of NuclearReactor Regulation (NRR) project manager.harles E. Rossi, DirectorDivision of Operational Events AssessmentOffice of Nuclear Reactor RegulationTechnical contacts: Thomas Koshy, NRR(301) 504-1176Iqbal Ahmed, NRR(301) 504-3252

Attachments:

1. Figure 1. Test Configuration that Excludes theEffect of Snubbers2. List of Recently Issued NRC Information Notices Attachment 1IN 92-33April 30, 1992 PRESSURE SENSING DEVICEUBBERSTi LOW SIDE BLOCK VALVETO PROCESSCONNECTIONFigure 1.Test Configuration That Excludes the Effect of Snubbers mz-C1>cnmZcmm0 F)-0>~03<>CA LM2aC/)cnD*o m(AnU).200'Im,,00rn ->CAAttachment 2IN 92-33April 30, 1992 LIST OF RECENTLY ISSUEDNRC INFORMATION NOTICESInformation Date ofNotice No. Subject Issuance Issued to92-32 Problems Identified with 04/29/92 All holders of OL or CPsEmergency Ventilation for nuclear power reactors.Systems for Near-Site(Within 10 Miles) Emer-gency Operations Facili-ties and Technical SupportCenters92-31 Electrical Connection 04/27/92 All holders of OLs or CPsProblem in Johnson for nuclear power reactors.Yokogawa CorporationYS-80 Programmable Indi-cating Controllers92-30 Falsification of Plant 04/23/92 All holders of OLs or CPsRecords for nuclear power reactorsand all licensed operatorsand senior operators.92-21, Spent Fuel Pool Re- 04/22/92 All holders of OLs or CPsSupp. I activity Calculations for nuclear power reactors.92-29 Potential Breaker His- 04/17/92 All holders of OLs or CPscoordination Caused by for nuclear power reactors.Instantaneous TripCircuitry92-28 -Inadequate Fire Suppres- 04/08/92 All holders of OLs or CPssian System Testing for nuclear power reactors.92-27 Thermally Induced Acceler- 04/03/92 All holders of OLs or CPsated Aging and Failure of for nuclear power reactors.ITE/GOULD A.C. Relays Usedin Safety-Related Applic-ations92-26 Pressure Locking of Motor- 04/02/92 All holders of OLs or CPsOperated Flexible Wedge for nuclear power reactors.Gate ValvesOL = Operating LicenseC? -Construction Permit((.< \

IN 92-33April 30, 1992 Snubber time delay will not be detected in response time testing conducteddirectly at the sensing instrument (see Figure 1.) The effect of a snubberwill differ from sensor to sensor because of differences in the volumetricdisplacement of fluid within the pressure sensing mechanisms. System responsetime can also be degraded by the accumulation of foreign material in sensingline snubbers.The NRC's Office of Nuclear Regulatory Research is conducting a generic studyon the performance of pressure instrumentation at nuclear power plants. Thestaff plans to publish the results in NUREG/CR 5851, "Long Term Performanceand Aging Characteristics of Nuclear Plant Pressure Transmitters." The staffhas completed a part of this effort, and the results of tests conducted onpressure sensor response time testing were published in an ISA (InstrumentSociety of America) transaction 91-720, "Response Time Testing of PressureTransmitters in Nuclear Power Plants." This publication addresses variouscauses for delays in sensor response and documents that significant timedelays can occur.This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contact oneof the technical contacts listed below or the appropriate Office of NuclearReactor Regulation (NRR) project manager. Orginal Signed byCharles E. RossiCharles E. Rossi, DirectorDivision of Operational Events AssessmentOffice of Nuclear Reactor RegulationTechnical contacts: Thomas Koshy, NRR(301) 504-1176Iqbal Ahmed, NRR(301) 504-3252

Attachments:

1. Figure 1. Test Configuration that Excludes theEffect of Snubbers2. List of Recently Issued NRC Information NoticesReviewed by J. Main, Technical Editor, on 02/07/92*SEE PREVIOUS CONCURRENCEOFC :OEAB:DOEA :SICB:DST :SC:OEAB:DOEA:C:SICB:DST :C:OEAB:DOEA :C:OGCB:DOEA :D:DOEANAME :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 92OFFICIAL RECORD COPYDocument Name: IN 92-33 IN 92-XXApril xx, 1992 Since the snubbers are mounted upstream of the sensors, this time delay willnot be experienced in response time testing conducted directly at the sensinginstrument (see Figure 1.) These snubbers could degrade and reduce the flowthrough the device, further increasing the time delay. The effect of a snubberwould differ between various sensors because of the differences in the volumetricdisplacement of fluid within their pressure sensing mechanism. System responsetime could be degraded by the presence and condition of snubbers in the sensingline.The NRC's Office of Nuclear Regulatory Research is conducting a generic studyon the performance of pressure instrumentation at nuclear power plants. Thestaff plans to publish this study report as NUREG/CR 5851, "Long Term Performanceand Aging Characteristics of Nuclear Plant Pressure Transmitters." The staffcompleted a part of this effort and the result of tests conducted on pressuresensor response time testing was published in an ISA (Instrument Society ofAmerica) transaction 91-720, "Response Time Testing of Pressure Transmitters inNuclear Power Plants." This publication addresses various causes for thedelays in sensor response and documents that significant time delays can occur.This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contact oneof the technical contacts listed below or the appropriate Office of NuclearReactor Regulation (NRR) project manager.Charles E. Rossi, DirectorDivision of Operational Events AssessmentOffice of Nuclear Reactor RegulationTechnical contacts: Thomas Koshy, NRR(301) 504-1176Iqbal Ahmed, NRR(301) 504-3252

Attachments:

1. Figure 1. Test Configuration that Excludes theEffect of Snubbers2. List of Recently Issued NRC Information NoticesReviewed 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:DOEANAME :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 : / /92OFFICIAL RECORD COPYDocument Name: IN/KOSHY IN 92-XXMarch xx, 1992 Since the snubbers are mounted upstream of the sensors, this time delay willnot be experienced in response time testing conducted directly at the sensinginstrument. These snubbers could degrade and reduce the flow through thedevice, further increasing the time delay. The effect of a snubber woulddiffer between various sensors because of the differences in the volumetricdisplacement of fluid within their pressure sensing mechanism. System responsetime could be degraded by the presence and condition of snubbers in the sensingline.The NRC's Office of Nuclear Regulatory Research is conducting a generic studyon the performance of pressure instrumentation at nuclear power plants. Thestaff plans to publish this study report as NUREG/CR 5851, "Long Term Performanceand Aging Characteristics of Nuclear Plant Pressure Transmitters." The staffcompleted a part of this effort and the result of tests conducted on pressuresensor response time testing was published in an ISA (Instrument Society ofAmerica) transaction 91-720, "Response Time Testing of Pressure Transmitters inNuclear Power Plants." This publication addresses various causes for thedelays in sensor response and documents that significant time delays can occur.This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contact oneof the technical contacts listed below or the appropriate Office of NuclearReactor Regulation (NRR) project manager.Charles E. Rossi, DirectorDivision of Operational Events AssessmentOffice of Nuclear Reactor RegulationTechnical contacts: Thomas Koshy, NRR(301) 504-1176Iqbal Ahmed, NRR(301) 504-3252

Attachment:

List of Recently Issued NRC Information NoticesReviewed by J. Main, Technical Editor, on 02/07/92*SEE PREVIOUS CONCURRENCEOFC :OEAB:DOEA :SICB:DST :SC:OEB:DOEA SICPST :COEAB:DOEA :C:OGCB:DOEA :D:DOEANAME :TKoshy* :IAhmed* :DFsTcher :SN-- erry :ACxt :CBerlinger :CRossiDATE :02/12/92 :03/03/92 :3 /6 /92 :S,48/92 : 5It"/92 : / /92 : / /92OFFICIAL RECORD COPYDocument Name: IN/KOSHY IN 92-XXFebruary xx, 1992 The NRC's Office of Nuclear Regulatory Research is conducting a generic studyon the performance of pressure instrumentation at nuclear power plants. Thestaff plans to publish this study report as NUREG/CR 5851, "Long Term Performanceand Aging Characteristics of Nuclear Plant Pressure Transmitters." The staffcompleted a part of this effort and the result of tests conducted on pressuresensor response time testing was published in an ISA (Instrument Society ofAmerica) transaction 91-720, "Response Time Testing of Pressure Transmitters inNuclear Power Plants." This publication addresses various causes for thedelays in sensor response and documents a 3-second delay for a snubber in thesensing line.Since the snubbers are mounted upstream of the sensors, this time delay willnot be experienced in response time testing conducted directly at the sensinginstrument. These snubbers could degrade and reduce the flow through thedevice, further increasing the time delay. The effect of a snubber woulddiffer between various sensors because of the differences in the volumetricdisplacement of fluid within their pressure sensing mechanism. System responsetime could be degraded by the presence and condition of snubbers in the sensingline.This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contact oneof the technical contacts listed below or the appropriate Office of NuclearReactor Regulation (NRR) project manager.Charles E. Rossi, DirectorDivision of Operational Events AssessmentOffice of Nuclear Reactor RegulationTechnical contacts: Thomas Koshy, NRR(301) 504-1176Iqbal Ahmed, NRR(301) 504-3252

Attachment:

List of Recently Issued NRC Information NoticesReviewed by J. Main, Technical Editor, on 02/07/92*SEE PREVIOUS CONCURRENCEOFC :OEAB:DOEA :SICB:DST :SC:OEAB:DOEA:C:SICB:DST :C:OEAB:DOEA :C:OGCB:DOEA :D:DOEANAME :TKoshy* :IAhmed ( :DFischer :SNewberry :AChaffee :CBerlinger :CRossiDATE :02/12/92 :3 /3/92 : / /92 : / /92 : / /92 : / /92 : / /92OFFICIAL RECORD COPYDocument Name: IN/KOSHY IN 92-XXFebruary xx, 1992 The NRC's Office of Nuclear Regulatory Research is studying the performance ofinstrumentation. The staff plans to publish this study as NUREG/CR 5851, "LongTerm Performance and Aging Characteristics of Nuclear Plant Pressure Transmitters."The staff completed a part of this effort and the result of tests conducted onpressure sensor response time testing was published in an ISA (InstrumentSociety of America) transaction 91-720, "Response Time Testing of PressureTransmitters in Nuclear Power Plants." This publication addresses variouscauses for the delays in sensor response and documents a 3-second delay for asnubber in the sensing line.Since the snubbers are mounted upstream of the sensors, this time delay willnot be experienced in response time testing conducted directly at the sensinginstrument. These snubbers could degrade and reduce the flow through thedevice, further increasing the time delay. The effect of a snubber woulddiffer between various sensors because of the differences in the volumetricdisplacement of fluid within their pressure sensing mechanism. System responsetime could be degraded by the presence and condition of snubbers in the sensingline.This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contact oneof the technical contacts listed below or the appropriate Office of NuclearReactor Regulation (NRR) project manager.Charles E. Rossi, DirectorDivision of Operational Events AssessmentOffice of Nuclear Reactor RegulationTechnical contacts: Thomas Koshy, NRR(301) 504-1176Iqbal Ahmed, NRR(301) 504-3252

Attachment:

List of Recently Issued NRC Information NoticesReviewed by J. Main, Technical Editor, on 02/07/92OFC :OEAB:DOEA :SICB:DST :SC:OEAB:DOEA:C:SICB:DST :C:OEAB:DOEA :C:OGCB:DOEA :D:DOEANAME :TKoshy Tf :IAhmed :DFischer :SNewberry :AChaffee :CBerlinger :CRossiDATE :2_//2/92 :/ /92 ://92 ://92 ://92 ://92 :/ /92OFFICIAL RECORD COPYDocument Name: IN/KOSHY