Information Notice 1992-36, Intersystem LOCA Outside Containment: Difference between revisions

From kanterella
Jump to navigation Jump to search
(Created page by program invented by StriderTol)
 
(Created page by program invented by StriderTol)
 
(4 intermediate revisions by the same user not shown)
Line 3: Line 3:
| issue date = 05/07/1992
| issue date = 05/07/1992
| title = Intersystem LOCA Outside Containment
| title = Intersystem LOCA Outside Containment
| author name = Rossi C E
| author name = Rossi C
| author affiliation = NRC/NRR
| author affiliation = NRC/NRR
| addressee name =  
| addressee name =  
Line 13: Line 13:
| document type = NRC Information Notice
| document type = NRC Information Notice
| page count = 10
| page count = 10
| revision = 0
}}
}}
{{#Wiki_filter:UNITED STATESNUCLEAR REGULATORY COMMISSIONOFFICE OF NUCLEAR REACTOR REGULATIONWASHINGTON, D.C. 20555May 7, 1992NRC INFORMATION NOTICE 92-36: INTERSYSTEM LOCA OUTSIDE CONTAINMENT
{{#Wiki_filter:UNITED STATES
 
NUCLEAR REGULATORY COMMISSION
 
OFFICE OF NUCLEAR REACTOR REGULATION
 
WASHINGTON, D.C. 20555 May 7, 1992 NRC INFORMATION NOTICE 92-36:   INTERSYSTEM LOCA OUTSIDE CONTAINMENT


==Addressees==
==Addressees==
All holders of operating licenses or construction permits for nuclear powerreactors.
All holders of operating licenses or construction permits for nuclear power
 
reactors.


==Purpose==
==Purpose==
The U.S. Nuclear Regulatory Commission (NRC) is issuing this information noticeto alert addressees of potential plant vulnerabilities to intersystem loss-of-coolant accidents (ISLOCAs). It is expected that recipients will reviewthe information for applicability to their facilities and consider actions, asappropriate. However, suggestions contained in this information notice are notNRC requirements; therefore, no specific action or written response is required.This information notice provides information gathered during a concerted NRCstaff effort to study plant vulnerabilities to ISLOCAs. The staff gatheredthis information by performing (a) detailed evaluations of operating events,(b) inspections of a limited sample of pressurized water reactors (PWRs), and(c) extensive analyses of the sample PWRs. The information may be of use inrecipients' individual plant examination (IPE) programs.BackgroundThe ISLOCA is a class of accidents in which a break occurs in a system con-nected to the reactor coolant system (RCS), causing a loss of the primarysystem inventory. This type of accident can occur when a low pressure system,such as the residual heat removal (RHR) system, is inadvertently exposed tohigh RCS pressures beyond its capacity. ISLOCAs of most concern are thosethat can discharge the break flow outside the reactor containment building,primarily because they can result in high offsite radiological consequences butalso because the RCS inventory lost cannot be retrieved for long-term corecooling during the recirculation phase.In the "Reactor Safety Study," (WASH-1400), published in 1975, and inNUREG-1150, "Severe Accident Risks: An Assessment for Five U.S. Nuclear PowerPlants," the NRC described the ISLOCA outside containment as an event of lowcore damage frequency, but as one of the main contributors to plant risk. Inthose studies the NRC referred to the ISLOCA as "Event-V." Most probabilisticrisk assessments (PRAs) have also shown that the ISLOCA is very unlikely.However, these PRAs typically have modelled only those Event-V sequences thatinclude only the catastrophic failure of check valves that isolate the RCS from92050_ 45AMA IN 92-36May 7, 1992 low pressure systems. These PRAs included little consideration of human errorsleading to an ISLOCA. Also, most existing PRAs have given little or no creditfor operator actions to terminate an ISLOCA or to mitigate its radiologicalconsequences if core melt were to occur.On January 22, 1992, the Virginia Electric Power Company, licensee for theNorth Anna Power Station, reported that the RHR relief valves would not passthe design-basis flow to relieve an overpressurization of the RHR system whenthe latter is aligned to the RCS. The function of these relief valves isimportant when the RCS is water solid and therefore susceptible to overpressur-ization events, such as from a charging-letdown flow mismatch or a temperaturechange.The licensee made this report after conducting an engineering evaluation torespond to a notification by the nuclear steam supply vendor, the WestinghouseElectric Corporation. In February 1990, Westinghouse reviewed the RHR reliefvalve design basis for the Westinghouse Owners Group and recommended that itscustomers review the following three items:The adequacy of the RHR relief valves for protecting against coldoverpressure eventsDischarge capability of relief valves for probable back pressuresDesign basis commitments for valve specifications, commitments in thefinal safety analysis report, and technical specificationsThe NRC has issued several information notices to discuss certain operationalevents regarding ISLOCAs. In IN 90-05, "Inter-system Discharge of ReactorCoolant," the staff. discussed an event during which about 68,000 gallons ofreactor water was discharged outside the containment. The staff has alsoanalyzed operational experience and documented its findings in augmentedinspection team (AIT) reports. On October 23, 1990, the staff issued AITReport 50-456/90-020 on an event at Braidwood that resulted in primary waterleakage outside the containment and in the contamination of three personnel,one of whom received a second degree burn. Table 3 is a selected list ofinformation notices and AIT reports that the staff has issued on ISLOCAs andrelated events.DiscussionAlthough no ISLOCA has caused core damage, accumulated operational experience,both in the United States and abroad, indicates that ISLOCA-like events haveoccurred at a rate higher than expected. In conducting this study, the staffdefined an ISLOCA-like event, or an ISLOCA precursor, as an event that resultsfrom the failure, degradation, or inadvertent opening of the pressure isolationvalves (PIYs) between the RCS and lower pressure systems. An ISLOCA precursormay become an ISLOCA if it occurs during different plant conditions, or if someof the failures occur together.The NRC staff conducted root cause analyses of ISLOCA precursors, extensiveplant inspections, and detailed analyses of a sample of PWRs. These analyses IN 92-36May 7, 1992 included thermal-hydraulic analyses, fragility analyses to determine the likelysizes and locations of a break, and human reliability analyses. The staff usedthe results of these analyses in PRAs to gain insights about the significantcontributors to ISLOCA risk.The staff directed the studies described in this information notice towardsfinding vulnerabilities of PWR plants to ISLOCAs, since the primary pressurespresent in PWRs are greater than those found in boiling water reactors (BWRs),while the design pressures of low pressure systems are about the same in bothPWRs and BWRs. However, BWR licensees also may find this information to berelevant to their plants.Upon conducting these studies, the staff made the following observations on theISLOCA risk at nuclear power plants:1. The estimated core damage frequency caused by ISLOCAs could be greaterthan was estimated in PRAs for some plants.The ISLOCA risk depends on both the accident initiators and the capabili-ties for recovery. These factors vary from plant to plant. The maincontributors to ISLOCA initiation and/or recovery include (a) human errorsand (b) the effects of the accident-caused harsh environment on plantequipment and recovery activities. Both factors have significant uncer-tainties. Existing PRAs have provided little or no treatment of thesefactors. Plants that are particularly vulnerable to either of these twofactors could have a higher ISLOCA risk than indicated by existing PRAs.2. Most plants lack contingency plans to provide backup water supplies thatcan be transferred readily to provide long-term core cooling after anISLOCA.By examining a plant's emergency procedures, a licensee can findinsights for improving the plant's features to address the concerns forboth ISLOCAs and other accidents.3. The root cause analyses of operational events indicate that ISLOCA precur-sors most likely would be initiated by human errors, notably duringtesting and maintenance or because of procedural deficiencies. This maybe attributed to the general lack of awareness of the possibility orconsequences of an ISLOCA.Licensees may significantly reduce the probability of ISLOCA precursorsby improving the ability of operators and maintenance personnel to recog-nize ISLOCAs, mechanisms that can cause them, actions to prevent them, andmethods to manage them if they occur.4. Most observed ISLOCA precursors have low public risk consequences. However,an ISLOCA precursor can require a shutdown or extension of a shutdown,require radioactivity cleanup operations, and cause personnel injur IN 92-36May 7, 1992 Table 1 presents the staff's observations from root cause analyses and plantinspections. Table 2 presents insights gained from the ISLOCA PRAs.The staff is completing its ISLOCA research program under Generic Issue 105,"Intersystem Loss of Coolant Accidents in Light Water Reactors." Upon complet-ing this research, the staff may issue further generic correspondence tolicensees.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.es ERossi, DrectrDivision of Operational Events AssessmentOffice of Nuclear Reactor RegulationTechnical contacts: Kazimieras Campe, NRR(301) 504-1092Sammy Diab, RES(301) 492-3914Gary Burdick, RES(301) 492-3812
The U.S. Nuclear Regulatory Commission (NRC) is issuing this information notice
 
to alert addressees of potential plant vulnerabilities to intersystem loss-of- coolant accidents (ISLOCAs). It is expected that recipients will review
 
the information for applicability to their facilities and consider actions, as
 
appropriate. However, suggestions contained in this information notice are not
 
NRC requirements; therefore, no specific action or written response is required.
 
This information notice provides information gathered during a concerted NRC
 
staff effort to study plant vulnerabilities to ISLOCAs. The staff gathered
 
this information by performing (a) detailed evaluations of operating events, (b) inspections of a limited sample of pressurized water reactors (PWRs), and
 
(c) extensive analyses of the sample PWRs. The information may be of use in
 
recipients' individual plant examination (IPE) programs.
 
Background
 
The ISLOCA is a class of accidents in which a break occurs in a system con- nected to the reactor coolant system (RCS), causing a loss of the primary
 
system inventory. This type of accident can occur when a low pressure system, such as the residual heat removal (RHR) system, is inadvertently exposed to
 
high RCS pressures beyond its capacity. ISLOCAs of most concern are those
 
that can discharge the break flow outside the reactor containment building, primarily because they can result in high offsite radiological consequences but
 
also because the RCS inventory lost cannot be retrieved for long-term core
 
cooling during the recirculation phase.
 
In the "Reactor Safety Study," (WASH-1400), published in 1975, and in
 
NUREG-1150, "Severe Accident Risks: An Assessment for Five U.S. Nuclear Power
 
Plants," the NRC described the ISLOCA outside containment as an event of low
 
core damage frequency, but as one of the main contributors to plant risk. In
 
those studies the NRC referred to the ISLOCA as "Event-V." Most probabilistic
 
risk assessments (PRAs) have also shown that the ISLOCA is very unlikely.
 
However, these PRAs typically have modelled only those Event-V sequences that
 
include only the catastrophic failure of check valves that isolate the RCS from
 
AMA
 
92050_  45
 
IN 92-36 May 7, 1992 low pressure systems. These PRAs   included little consideration of human errors
 
leading to an ISLOCA. Also, most   existing PRAs have given little or no credit
 
for operator actions to terminate an ISLOCA or to mitigate its radiological
 
consequences if core melt were to occur.
 
On January 22, 1992, the Virginia Electric Power
 
North Anna Power Station, reported that the RHR Company, licensee for the
 
relief valves would not pass
 
the design-basis flow to relieve an overpressurization
 
the latter is aligned to the RCS. The function               of the RHR system when
 
important when the RCS is water solid and thereforeof these    relief valves is
 
ization events, such as from a charging-letdown         susceptible      to overpressur- flow   mismatch     or a temperature
 
change.
 
The licensee made this report after conducting
 
respond to a notification by the nuclear steam an engineering evaluation to
 
supply vendor, the Westinghouse
 
Electric Corporation. In February 1990, Westinghouse
 
valve design basis for the Westinghouse Owners             reviewed the RHR relief
 
customers review the following three items:       Group  and    recommended that its
 
The adequacy of the RHR relief valves for protecting
 
overpressure events                                        against cold
 
Discharge capability of relief valves for probable
 
back pressures
 
Design basis commitments for valve specifications, final safety analysis report, and technical specificationscommitments in the
 
The NRC has issued several information notices
 
to discuss certain operational
 
events regarding ISLOCAs. In IN 90-05, "Inter-system
 
Coolant," the staff. discussed an event during             Discharge of Reactor
 
which
 
reactor water was discharged outside the containment.     about    68,000 gallons of
 
analyzed operational experience and documented               The    staff has also
 
inspection team (AIT) reports. On October 23,     its  findings      in augmented
 
Report 50-456/90-020 on an event at Braidwood     1990,  the    staff  issued AIT
 
that resulted in primary water
 
leakage outside the containment and in the contamination
 
one of whom received a second degree burn. Table                 of three personnel, information notices and AIT reports that the           3 is  a  selected list of
 
related events.                                staff   has   issued   on ISLOCAs and
 
Discussion
 
Although no ISLOCA has caused core damage, accumulated
 
both in the United States and abroad, indicates               operational experience, occurred at a rate higher than expected. In         that  ISLOCA-like      events have
 
conducting
 
defined an ISLOCA-like event, or an ISLOCA precursor,           this    study,  the staff
 
from the failure, degradation, or inadvertent               as    an  event  that results
 
valves (PIYs) between the RCS and lower pressure opening of the pressure isolation
 
may become an ISLOCA if it occurs during differentsystems. An ISLOCA precursor
 
of the failures occur together.                         plant conditions, or if some
 
===The NRC staff conducted root cause analyses of===
plant inspections, and detailed analyses of a ISLOCA precursors, extensive
 
sample of PWRs. These analyses
 
IN 92-36 May 7, 1992 to determine the likely
 
included thermal-hydraulic analyses, fragility analysesanalyses. The staff used
 
sizes and locations of a break, and human reliability about the significant
 
the results of these analyses in PRAs to gain insights
 
contributors to ISLOCA risk.
 
notice towards
 
The staff directed the studies described in this information
 
since    the  primary    pressures
 
finding vulnerabilities of PWR plants to ISLOCAs,             water    reactors  (BWRs),
present in PWRs are greater than those found     in boiling
 
systems  are  about    the same  in  both
 
while the design pressures of low pressure               this    information    to  be
 
PWRs and BWRs. However, BWR licensees also     may find
 
relevant to their plants.
 
following observations on the
 
===Upon conducting these studies, the staff made the===
ISLOCA risk at nuclear power plants:
                                                                  could be greater
 
1.   The estimated core damage frequency caused by ISLOCAs
 
than was estimated in PRAs for some plants.
 
and the capabili- The ISLOCA risk depends on both the accident initiatorsto  plant.    The main
 
ties for recovery. These factors   vary   from plant
 
and/or   recovery   include     (a) human errors
 
contributors to ISLOCA initiation                                      on plant
 
and (b) the effects of the accident-caused harsh environment significant uncer- equipment and recovery activities. Both factors have       treatment of these
 
tainties. Existing PRAs have provided little or noto either of these two
 
factors. Plants that are particularly vulnerable               by existing PRAs.
 
factors could have a higher ISLOCA risk than indicated
 
water supplies that
 
2.   Most plants lack contingency plans to provide backup cooling after an
 
can be transferred readily to provide long-term core
 
ISLOCA.
 
can find
 
By examining a plant's emergency procedures, a licensee the concerns for
 
insights for improving the plant's features to address
 
both ISLOCAs and other accidents.
 
indicate that ISLOCA precur-
  3. The root cause analyses of operational events errors,        notably during
 
sors most likely would be initiated by human                             This may
 
testing and maintenance or because of procedural     deficiencies.
 
of  the  possibility    or
 
be attributed to the general lack of awareness
 
consequences of an ISLOCA.
 
ISLOCA precursors
 
Licensees may significantly reduce the probability of personnel to recog- by improving the ability of operators and   maintenance
 
to prevent them, and
 
nize ISLOCAs, mechanisms that can cause them, actions
 
methods to manage them if they occur.
 
risk consequences. However,
  4. Most observed ISLOCA precursors have low publicextension of a shutdown, an ISLOCA precursor can require a shutdown   or
 
injury.
 
require radioactivity cleanup operations, and cause personnel
 
IN 92-36 May 7, 1992 Table 1 presents the staff's observations from root
 
inspections. Table 2 presents insights gained from cause analyses and plant
 
the ISLOCA PRAs.
 
The staff is completing its ISLOCA research program
 
"Intersystem Loss of Coolant Accidents in Light Waterunder Generic Issue 105, ing this research, the staff may issue further generic Reactors." Upon complet- licensees.                                              correspondence to
 
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.
 
es ERossi, Drectr
 
Division of Operational Events Assessment
 
Office of Nuclear Reactor Regulation
 
Technical contacts:   Kazimieras Campe, NRR
 
(301) 504-1092 Sammy Diab, RES
 
(301) 492-3914 Gary Burdick, RES
 
(301) 492-3812 Attachments:
1. Table 1. "Observed Plant Vulnerabilities to
 
2. Table 2. "ISLOCA Risk Insights"                  ISLOCA Precursors"
3. Table 3. "A Selected List of ISLOCA Reports
 
and References"
4. List of Recently Issued NRC Information Notices
 
Attachment 1 IN 92-36 May 7, 1992 Table 1. Observed Plant Vulnerabilities to ISLOCA Precursors
 
plant inspections)
(Obtained from root cause analyses of ISLOCA precursors and
 
1. Lack of awareness of the nature or consequences of ISLOCAs
 
especially
 
2.  Inadequate emergency procedures for ISLOCA outside containment, for non-power operational modes
 
3.  Poor or incorrect valve labels
 
plant
 
4.  Different nomenclature used for the same equipment in the same
 
5.  Poor coordination between concurrently run tests
 
opera-
6.  Miscommunications between the control room operators and auxiliary
 
but  understood
 
tors ("get the valve" is meant as "crack open  then  close,"
    to mean "open")
7.  Poor shift turn-over communications
 
8.    Poor post-maintenance testing or operability checks
 
9.    Inadequate application of independent verification
 
10.  Tendency not to check diverse instrument indications
 
during
 
11.  Tendency to commit personnel to extensive overtime work, especially
 
level  and the
 
shutdown and startup operations, thus increasing  the fatigue
 
likelihood of errors
 
Attachment 2 IN 92-36 May 7, 1992 Table 2. ISLOCA Risk Insights
 
(Obtained from ISLOCA PRAs)
                                                                          by an
 
1.  The staff's studies suggest that the core damage frequency caused for some
 
ISLOCA could be substantially greater than previous PRA  estimates
 
and
 
plants. This is primarily caused by the effects of operator errors during
 
harsh environments caused by the accident. Valve alignment    errors
 
transition between operating modes can be particularly important.
 
the
 
2.  Equipment qualified for a harsh environment is likely to survive  submersion
 
adverse ISLOCA temperature and humidity, but not the  possible
 
caused by flooding.
 
or
 
3.  Multiple system failures may result from the ISLOCA harsh environment to
 
flooding, depending on the size and location of the  break  in  relation
 
of
 
affected equipment, the separation of redundant trains, and the effect
 
fire sprays on flooding.
 
essen-
4.    ISLOCA recovery is limited by harsh environments, which may damageof loss
 
tial equipment thus complicating long-term cooling,  and  the  rate
 
of reactor water outside the containment. If the water is not quickly    has
 
replenished, an ISLOCA may lead to core damage, even after the leak
 
been isolated.
 
an ISLOCA
 
5.  Symptom-based procedures may lead the operator to realize that to  plant
 
has occurred. However, unless the emergency  procedures  refer
 
water, the  operator  may  have
 
provisions for conserving and replenishing
 
difficulty managing the accident.
 
6.  Most observed ISLOCA precursors have low risk consequences, primarily small
 
because of the presence of one or more of the following conditions:low
 
leak size, redundant means of detecting and isolating a leak, and
 
power or shutdown conditions.
 
Attachment 3 IN 92-36 May 7, 1992 Table 3. A Selected List of ISLOCA Reports and References
 
Identification            Title or Subject                            Date
 
Potential for Common-Mode Failure of              10/04/90
IN 90-64 HPSI Pumps or Release of Reactor Coolant
 
Outside Containment During a LOCA
 
Inter-system Discharge of Reactor Coolant          01/29/90
IN 90-05 IN 89-73            Potential Overpressurization of Low                11/01/89 Pressure Systems
 
AIT Report          An assessment of the 10/4/90 Braidwood            10/23/90
50-456/90-20        loss of reactor coolant inventory and
 
personnel contamination and injury
 
AIT Report          An assessment of the 4/12/89 Pilgrim                05/08/89
50-293/89-80        overpressurization event, which occurred
 
during the conduct of the RCIC logic test
 
ISLOCA Program Inspection of the Waterford        09/14/90
Inspection
 
Report              plant
 
50-382/90-200
                      ISLOCA Program Inspection of the Catawba          06/11/90
Inspection
 
Report              plants
 
50-413,414/90-200
Inspection          ISLOCA Program Inspection of the Davis              12/21/89 Report              Besse plant
 
50-346/89-201 Audit                Haddam Neck ISLOCA Audit Report: July 24  -        09/20/89 Report              August 4, 1989, Enclosure to Memorandum
 
Docket No. 50-213    from Frank J. Congel, NRC, to
 
Steven A. Varga, NRC*
NUREG/CR-5745        Assessment for ISLOCA Risks -                      June 91 Draft Methodology and Application:
                      Combustion Engineering Plant
 
NUREG/CR-5744      Assessment for ISLOCA Risks -                      Feb 91 Draft Methodology and Application:
                      Westinghouse Four-Loop Ice Condenser Plant
 
NUREG/CR-5604        Assessment for ISLOCA Risks -                      Feb 91 Draft Methodology and Application: Babcock
 
and Wilcox Nuclear Power Station
 
NUREG/CR-5124        Interfacing Systems LOCA, Boiling                  Feb 89 Water Reactors
 
NUREG/CR-5102        Interfacing Systems LOCA, Pressurized              Feb 89 Water Reactors
 
-A COpy OT this report is available in the NRC Public Document Room,
  2120 L Street, N.W., Washington, DC.
 
Attachment 4 IN 92-36 May 7, 1992 LIST OF RECENTLY ISSUED
 
NRC INFORMATION NOTICES
 
Information                                      Date of
 
Notice No.            Subject                    Issuance  Issued to
 
92-35          Higher Than Predicted Ero-      05/06/92  All holders of OLs or CPs
 
sion/Corrosion in Unisol-                  for nuclear power reactors.
 
able Reactor Coolant Pres- sure Boundary Piping Inside
 
Containment at A Boiling
 
Water Reactor
 
92-34          New Exposure Limits for          05/06/92  All licensees whose opera- Airborne Uranium and                      tions can cause airborne
 
Thorium                                    concentrations of uranium
 
and thorium.
 
92-33          Increased Instrument            04/30/92  All holders of OLs or CPs
 
Response Time When                        for nuclear power reactors.
 
Pressure Dampening
 
Devices are Installed
 
92-32          Problems Identified with        04/29/92  All holders of OLs or CPs
 
Emergency Ventilation                      for nuclear power reactors.
 
Systems for Near-Site
 
(Within 10 Miles) Emer- gency Operations Facili- ties and Technical Support
 
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. 1        activity Calculations                      for nuclear power reactors.
 
OL = Operating License
 
CP = Construction Permit
 
IN 92-36 May 7, 1992 Table 1 presents the staff's observations from root cause analyses and plant
 
inspections. Table 2 presents insights gained from the ISLOCA PRAs.
 
The staff is completing its ISLOCA research program under Generic Issue 105,
"Intersystem Loss of Coolant Accidents in Light Water Reactors." Upon complet- ing this research, the staff may issue further generic correspondence to
 
licensees.
 
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.
 
Original Signed by
 
Charles E Rei
 
Charles E. Rossi, Director
 
Division of Operational Events Assessment
 
Office of Nuclear Reactor Regulation
 
Technical contacts:  Kazimieras Campe, NRR
 
(301) 504-1092 Sammy Diab, RES
 
(301) 492-3914 Gary Burdick, RES
 
(301) 492-3812 Attachments:
1. Table 1. "Observed Plant Vulnerabilities to ISLOCA Precursors'
2. Table 2. "ISLOCA Risk Insights"
3. Table 3. "A Selected List of ISLOCA Reports and References"
4. List of Recently Issued NRC Information Notices
 
Document Name: IN 92-36
*See previous concurrence.
 
C/OGCB:DOEA:NRR D/DOEA:NRR
 
*CHBerlinger
 
04/24/92 RPB:ADM          D/DSIR:RES      C/RPSIB:DSIR:RES  RPSIB:DSIR:RES C/EIB:DSIR:RES
 
*TechEd          *WMinners        *KKniel            *GBurdick          *RLBaer
 
04/09/92        04/15/92        04/14/92          04/13/92            04/13/92 OGCB:DOEA:NRR    SC/RAB:DREP:NRR C/RAB:DREP:NRR      D/DREP:NRR          EIB:DSIR:RES
 
*CVHodge        *KCampe          *WBeckner          *FCongel            *SDiab
 
04/08/92        04/09/92        04/09/92          04/09/92            04/13/92
 
IN 92-XX
 
April xx, 1992 Table 1 presents the staff's observations from root cause analyses and plant
 
inspections. Table 2 presents insights gained from the ISLOCA PRAs.
 
The staff is completing its ISLOCA research program under Generic Issue 105,
"Intersystem Loss of Coolant Accidents in Light Water Reactors." Upon complet- ing this research, the staff may issue further generic correspondence to
 
licensees.
 
This information notice requires    no speci fic action or written response. If
 
you have any questions about the    informat ion 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:    Kazimieras Campe, NRR
 
(301) 504-1092 Sammy Diab, RES
 
(301) 492-3914 Gary Burdick, RES
 
(301) 492-3812 Attachments:
1. Table 1. "Observed Plant Vulnerabilities to ISLOCA Precursors"
2. Table 2. "ISLOCA Risk Insights"
3. Table 3. "A Partial List of ISLOCA Reports and References"
4. List of Recently Issued NRC Information Notices
 
Document Name: ISLOCA REV    2 C/OGCB:DOEA:NRR D/D1DOEA: NRR
 
CHBerling~* fj, CER tossi l


===Attachments:===
04/21/92gq"'    04/
1. Table 1. "Observed Plant Vulnerabilities to ISLOCA Precursors"2. Table 2. "ISLOCA Risk Insights"3. Table 3. "A Selected List of ISLOCA Reports and References"4. List of Recently Issued NRC Information Notices Attachment 1IN 92-36May 7, 1992 Table 1. Observed Plant Vulnerabilities to ISLOCA Precursors(Obtained from root cause analyses of ISLOCA precursors and plant inspections)1. Lack of awareness of the nature or consequences of ISLOCAs2. Inadequate emergency procedures for ISLOCA outside containment, especiallyfor non-power operational modes3. Poor or incorrect valve labels4. Different nomenclature used for the same equipment in the same plant5. Poor coordination between concurrently run tests6. Miscommunications between the control room operators and auxiliary opera-tors ("get the valve" is meant as "crack open then close," but understoodto mean "open")7. Poor shift turn-over communications8. Poor post-maintenance testing or operability checks9. Inadequate application of independent verification10. Tendency not to check diverse instrument indications11. Tendency to commit personnel to extensive overtime work, especially duringshutdown and startup operations, thus increasing the fatigue level and thelikelihood of errors Attachment 2IN 92-36May 7, 1992 Table 2. ISLOCA Risk Insights(Obtained from ISLOCA PRAs)1. The staff's studies suggest that the core damage frequency caused by anISLOCA could be substantially greater than previous PRA estimates for someplants. This is primarily caused by the effects of operator errors andharsh environments caused by the accident. Valve alignment errors duringtransition between operating modes can be particularly important.2. Equipment qualified for a harsh environment is likely to survive theadverse ISLOCA temperature and humidity, but not the possible submersioncaused by flooding.3. Multiple system failures may result from the ISLOCA harsh environment orflooding, depending on the size and location of the break in relation toaffected equipment, the separation of redundant trains, and the effect offire sprays on flooding.4. ISLOCA recovery is limited by harsh environments, which may damage essen-tial equipment thus complicating long-term cooling, and the rate of lossof reactor water outside the containment. If the water is not quicklyreplenished, an ISLOCA may lead to core damage, even after the leak hasbeen isolated.5. Symptom-based procedures may lead the operator to realize that an ISLOCAhas occurred. However, unless the emergency procedures refer to plantprovisions for conserving and replenishing water, the operator may havedifficulty managing the accident.6. Most observed ISLOCA precursors have low risk consequences, primarilybecause of the presence of one or more of the following conditions: smallleak size, redundant means of detecting and isolating a leak, and lowpower or shutdown condition Attachment 3IN 92-36May 7, 1992 Table 3. A Selected List of ISLOCA Reports and ReferencesIdentificationIN 90-64IN 90-05IN 89-73Title or SubjectPotential for Common-Mode Failure ofHPSI Pumps or Release of Reactor CoolantOutside Containment During a LOCAInter-system Discharge of Reactor CoolantPotential Overpressurization of LowPressure SystemsDate10/04/9001/29/9011/01/8910/23/9005/08/89AIT Report50-456/90-20AIT Report50-293/89-80An assessment of the 10/4/90 Braidwoodloss of reactor coolant inventory andpersonnel contamination and injuryAn assessment of the 4/12/89 Pilgrimoverpressurization event, which occurredduring the conduct of the RCIC logic testInspectionReport50-382/90-200InspectionReport50-413,414/90-200InspectionReport50-346/89-201ISLOCA Program InspectionplantISLOCA Program InspectionplantsISLOCA Program InspectionBesse plantof the Waterfordof the Catawbaof the Davis09/14/9006/11/9012/21/89AuditReportDocket No. 50-213NUREG/CR-5745NUREG/CR-5744NUREG/CR-5604NUREG/CR-5124NUREG/CR-5102Haddam Neck ISLOCA Audit Report: July 24 -August 4, 1989, Enclosure to Memorandumfrom Frank J. Congel, NRC, toSteven A. Varga, NRC*Assessment for ISLOCA Risks -Draft Methodology and Application:Combustion Engineering PlantAssessment for ISLOCA Risks -Draft Methodology and Application:Westinghouse Four-Loop Ice Condenser PlantAssessment for ISLOCA Risks -Draft Methodology and Application: Babcockand Wilcox Nuclear Power StationInterfacing Systems LOCA, BoilingWater ReactorsInterfacing Systems LOCA, PressurizedWater Reactors09/20/89June 91Feb 91Feb 91Feb 89Feb 89-A COpy OT this report is available in the NRC Public Document Room,2120 L Street, N.W., Washington, D Attachment 4IN 92-36May 7, 1992 LIST OF RECENTLY ISSUEDNRC INFORMATION NOTICESInformation Date ofNotice No. Subject Issuance Issued to92-3592-3492-3392-3292-3192-30Higher Than Predicted Ero-sion/Corrosion in Unisol-able Reactor Coolant Pres-sure Boundary Piping InsideContainment at A BoilingWater ReactorNew Exposure Limits forAirborne Uranium andThoriumIncreased InstrumentResponse Time WhenPressure DampeningDevices are InstalledProblems Identified withEmergency VentilationSystems for Near-Site(Within 10 Miles) Emer-gency Operations Facili-ties and Technical SupportCentersElectrical ConnectionProblem in JohnsonYokogawa CorporationYS-80 Programmable Indi-cating ControllersFalsification of PlantRecordsSpent Fuel Pool Re-activity Calculations05/06/9205/06/9204/30/9204/29/9204/27/9204/23/9204/22/92All holders of OLs or CPsfor nuclear power reactors.All licensees whose opera-tions can cause airborneconcentrations of uraniumand thorium.All holders of OLs or CPsfor nuclear power reactors.All holders of OLs or CPsfor nuclear power reactors.All holders of OLs or CPsfor nuclear power reactors.All holders of OLs or CPsfor nuclear power reactorsand all licensed operatorsand senior operators.All holders of OLs or CPsfor nuclear power reactors.92-21,Supp. 1OL = Operating LicenseCP = Construction Permit IN 92-36May 7, 1992 Table 1 presents the staff's observations from root cause analyses and plantinspections. Table 2 presents insights gained from the ISLOCA PRAs.The staff is completing its ISLOCA research program under Generic Issue 105,"Intersystem Loss of Coolant Accidents in Light Water Reactors." Upon complet-ing this research, the staff may issue further generic correspondence tolicensees.This information notice requiresyou have any questions about theof the technical contacts listedReactor Regulation (NRR) projectno specific action or written response. Ifinformation in this notice, please contact onebelow or the appropriate Office of Nuclearmanager.Original Signed byCharles E ReiCharles E. Rossi, DirectorDivision of Operational Events AssessmentOffice of Nuclear Reactor RegulationTechnical contacts:Kazimieras Campe, NRR(301) 504-1092Sammy Diab, RES(301) 492-3914Gary Burdick, RES(301) 492-3812
RPB:ADM          D/D g kS          CL        SI R:RES RQ    DSIR:RES C/EIB:D IRRES


===Attachments:===
TechEd J7Hh9q    W"                                   GB      k      RLBaerXiF'
1. Table 1. "Observed Plant Vulnerabilities to ISLOCA Precursors'2. Table 2. "ISLOCA Risk Insights"3. Table 3. "A Selected List of ISLOCA Reports and References"4. List of Recently Issued NRC Information NoticesDocument Name: IN 92-36*See previous concurrence.C/OGCB:DOEA:NRR D/DOEA:NRR*CHBerlinger04/24/92RPB:ADM*TechEd04/09/92D/DSIR:RES*WMinners04/15/92C/RPSIB:DSIR:RES*KKniel04/14/92RPSIB:DSIR:RES*GBurdick04/13/92C/EIB:DSIR:RES*RLBaer04/13/92OGCB:DOEA:NRR*CVHodge04/08/92SC/RAB:DREP:NRR*KCampe04/09/92C/RAB:DREP:NRR*WBeckner04/09/92D/DREP:NRR*FCongel04/09/92EIB:DSIR:RES*SDiab04/13/92 IN 92-XXApril xx, 1992 Table 1 presents the staff's observations from root cause analyses and plantinspections. Table 2 presents insights gained from the ISLOCA PRAs.The staff is completing its ISLOCA research program under Generic Issue 105,"Intersystem Loss of Coolant Accidents in Light Water Reactors." Upon complet-ing this research, the staff may issue further generic correspondence tolicensees.This information notice requires no speciyou have any questions about the informatof the technical contacts listed below orReactor Regulation (NRR) project manager.fic action or written response. Ifion in this notice, please contact onethe appropriate Office of NuclearCharles E. Rossi, DirectorDivision of Operational Events AssessmentOffice of Nuclear Reactor RegulationTechnical contacts:Kazimieras Campe, NRR(301) 504-1092Sammy Diab, RES(301) 492-3914Gary Burdick, RES(301) 492-3812
04/ q/92        04/ 15~/ 92      04/A//92          04//3/92      04//3/92 OGCB:DOEA: RR    SC/IRAB: REP:NRR C/RAB:DREP:IER    D/DREP:N      EIB:DSIR L>
CVHodge US9      KCaiimp          WBeckner    Xyt    FCongel        SDiab


===Attachments:===
04/od/92        04/ I9/9          04/A /92           04/9 /92        04/,3/92/}}
1. Table 1. "Observed Plant Vulnerabilities to ISLOCA Precursors"2. Table 2. "ISLOCA Risk Insights"3. Table 3. "A Partial List of ISLOCA Reports and References"4. List of Recently Issued NRC Information NoticesDocument Name:C/OGCB:DOEA:NRR D/D1CHBerling~* fj, CER04/21/92gq"' 04/RPB:ADM D/DTechEd J7Hh9q W"04/ q/92 04/OGCB:DOEA: RR SC/ICVHodge US9 KCai04/od/92 04/ISLOCA REV 2DOEA: NRRtossi lg kS15~/ 92RAB: REP:NRRimpI9/9C L SI R:RES04/A//92C/RAB:DREP:IERWBeckner Xyt04/A /92R Q DSIR:RESGB k04//3/92D/DREP:NFCongel04/9 /92C/EIB:D IRRESRLBaerXiF'04//3/92EIB:DSIR L>SDiab04/,3/92/}}


{{Information notice-Nav}}
{{Information notice-Nav}}

Latest revision as of 03:22, 24 November 2019

Intersystem LOCA Outside Containment
ML031200356
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  Entergy icon.png
Issue date: 05/07/1992
From: Rossi C
Office of Nuclear Reactor Regulation
To:
References
IN-92-036, NUDOCS 9205010045
Download: ML031200356 (10)
v • d • e


UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 May 7, 1992 NRC INFORMATION NOTICE 92-36: INTERSYSTEM LOCA OUTSIDE CONTAINMENT

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 of potential plant vulnerabilities to intersystem loss-of- coolant accidents (ISLOCAs). It is expected that recipients will review

the information for applicability to their facilities and consider actions, as

appropriate. However, suggestions contained in this information notice are not

NRC requirements; therefore, no specific action or written response is required.

This information notice provides information gathered during a concerted NRC

staff effort to study plant vulnerabilities to ISLOCAs. The staff gathered

this information by performing (a) detailed evaluations of operating events, (b) inspections of a limited sample of pressurized water reactors (PWRs), and

(c) extensive analyses of the sample PWRs. The information may be of use in

recipients' individual plant examination (IPE) programs.

Background

The ISLOCA is a class of accidents in which a break occurs in a system con- nected to the reactor coolant system (RCS), causing a loss of the primary

system inventory. This type of accident can occur when a low pressure system, such as the residual heat removal (RHR) system, is inadvertently exposed to

high RCS pressures beyond its capacity. ISLOCAs of most concern are those

that can discharge the break flow outside the reactor containment building, primarily because they can result in high offsite radiological consequences but

also because the RCS inventory lost cannot be retrieved for long-term core

cooling during the recirculation phase.

In the "Reactor Safety Study," (WASH-1400), published in 1975, and in

NUREG-1150, "Severe Accident Risks: An Assessment for Five U.S. Nuclear Power

Plants," the NRC described the ISLOCA outside containment as an event of low

core damage frequency, but as one of the main contributors to plant risk. In

those studies the NRC referred to the ISLOCA as "Event-V." Most probabilistic

risk assessments (PRAs) have also shown that the ISLOCA is very unlikely.

However, these PRAs typically have modelled only those Event-V sequences that

include only the catastrophic failure of check valves that isolate the RCS from

AMA

92050_ 45

IN 92-36 May 7, 1992 low pressure systems. These PRAs included little consideration of human errors

leading to an ISLOCA. Also, most existing PRAs have given little or no credit

for operator actions to terminate an ISLOCA or to mitigate its radiological

consequences if core melt were to occur.

On January 22, 1992, the Virginia Electric Power

North Anna Power Station, reported that the RHR Company, licensee for the

relief valves would not pass

the design-basis flow to relieve an overpressurization

the latter is aligned to the RCS. The function of the RHR system when

important when the RCS is water solid and thereforeof these relief valves is

ization events, such as from a charging-letdown susceptible to overpressur- flow mismatch or a temperature

change.

The licensee made this report after conducting

respond to a notification by the nuclear steam an engineering evaluation to

supply vendor, the Westinghouse

Electric Corporation. In February 1990, Westinghouse

valve design basis for the Westinghouse Owners reviewed the RHR relief

customers review the following three items: Group and recommended that its

The adequacy of the RHR relief valves for protecting

overpressure events against cold

Discharge capability of relief valves for probable

back pressures

Design basis commitments for valve specifications, final safety analysis report, and technical specificationscommitments in the

The NRC has issued several information notices

to discuss certain operational

events regarding ISLOCAs. In IN 90-05, "Inter-system

Coolant," the staff. discussed an event during Discharge of Reactor

which

reactor water was discharged outside the containment. about 68,000 gallons of

analyzed operational experience and documented The staff has also

inspection team (AIT) reports. On October 23, its findings in augmented

Report 50-456/90-020 on an event at Braidwood 1990, the staff issued AIT

that resulted in primary water

leakage outside the containment and in the contamination

one of whom received a second degree burn. Table of three personnel, information notices and AIT reports that the 3 is a selected list of

related events. staff has issued on ISLOCAs and

Discussion

Although no ISLOCA has caused core damage, accumulated

both in the United States and abroad, indicates operational experience, occurred at a rate higher than expected. In that ISLOCA-like events have

conducting

defined an ISLOCA-like event, or an ISLOCA precursor, this study, the staff

from the failure, degradation, or inadvertent as an event that results

valves (PIYs) between the RCS and lower pressure opening of the pressure isolation

may become an ISLOCA if it occurs during differentsystems. An ISLOCA precursor

of the failures occur together. plant conditions, or if some

The NRC staff conducted root cause analyses of

plant inspections, and detailed analyses of a ISLOCA precursors, extensive

sample of PWRs. These analyses

IN 92-36 May 7, 1992 to determine the likely

included thermal-hydraulic analyses, fragility analysesanalyses. The staff used

sizes and locations of a break, and human reliability about the significant

the results of these analyses in PRAs to gain insights

contributors to ISLOCA risk.

notice towards

The staff directed the studies described in this information

since the primary pressures

finding vulnerabilities of PWR plants to ISLOCAs, water reactors (BWRs),

present in PWRs are greater than those found in boiling

systems are about the same in both

while the design pressures of low pressure this information to be

PWRs and BWRs. However, BWR licensees also may find

relevant to their plants.

following observations on the

Upon conducting these studies, the staff made the

ISLOCA risk at nuclear power plants:

could be greater

1. The estimated core damage frequency caused by ISLOCAs

than was estimated in PRAs for some plants.

and the capabili- The ISLOCA risk depends on both the accident initiatorsto plant. The main

ties for recovery. These factors vary from plant

and/or recovery include (a) human errors

contributors to ISLOCA initiation on plant

and (b) the effects of the accident-caused harsh environment significant uncer- equipment and recovery activities. Both factors have treatment of these

tainties. Existing PRAs have provided little or noto either of these two

factors. Plants that are particularly vulnerable by existing PRAs.

factors could have a higher ISLOCA risk than indicated

water supplies that

2. Most plants lack contingency plans to provide backup cooling after an

can be transferred readily to provide long-term core

ISLOCA.

can find

By examining a plant's emergency procedures, a licensee the concerns for

insights for improving the plant's features to address

both ISLOCAs and other accidents.

indicate that ISLOCA precur-

3. The root cause analyses of operational events errors, notably during

sors most likely would be initiated by human This may

testing and maintenance or because of procedural deficiencies.

of the possibility or

be attributed to the general lack of awareness

consequences of an ISLOCA.

ISLOCA precursors

Licensees may significantly reduce the probability of personnel to recog- by improving the ability of operators and maintenance

to prevent them, and

nize ISLOCAs, mechanisms that can cause them, actions

methods to manage them if they occur.

risk consequences. However,

4. Most observed ISLOCA precursors have low publicextension of a shutdown, an ISLOCA precursor can require a shutdown or

injury.

require radioactivity cleanup operations, and cause personnel

IN 92-36 May 7, 1992 Table 1 presents the staff's observations from root

inspections. Table 2 presents insights gained from cause analyses and plant

the ISLOCA PRAs.

The staff is completing its ISLOCA research program

"Intersystem Loss of Coolant Accidents in Light Waterunder Generic Issue 105, ing this research, the staff may issue further generic Reactors." Upon complet- licensees. correspondence to

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.

es ERossi, Drectr

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical contacts: Kazimieras Campe, NRR

(301) 504-1092 Sammy Diab, RES

(301) 492-3914 Gary Burdick, RES

(301) 492-3812 Attachments:

1. Table 1. "Observed Plant Vulnerabilities to

2. Table 2. "ISLOCA Risk Insights" ISLOCA Precursors"

3. Table 3. "A Selected List of ISLOCA Reports

and References"

4. List of Recently Issued NRC Information Notices

Attachment 1 IN 92-36 May 7, 1992 Table 1. Observed Plant Vulnerabilities to ISLOCA Precursors

plant inspections)

(Obtained from root cause analyses of ISLOCA precursors and

1. Lack of awareness of the nature or consequences of ISLOCAs

especially

2. Inadequate emergency procedures for ISLOCA outside containment, for non-power operational modes

3. Poor or incorrect valve labels

plant

4. Different nomenclature used for the same equipment in the same

5. Poor coordination between concurrently run tests

opera-

6. Miscommunications between the control room operators and auxiliary

but understood

tors ("get the valve" is meant as "crack open then close,"

to mean "open")

7. Poor shift turn-over communications

8. Poor post-maintenance testing or operability checks

9. Inadequate application of independent verification

10. Tendency not to check diverse instrument indications

during

11. Tendency to commit personnel to extensive overtime work, especially

level and the

shutdown and startup operations, thus increasing the fatigue

likelihood of errors

Attachment 2 IN 92-36 May 7, 1992 Table 2. ISLOCA Risk Insights

(Obtained from ISLOCA PRAs)

by an

1. The staff's studies suggest that the core damage frequency caused for some

ISLOCA could be substantially greater than previous PRA estimates

and

plants. This is primarily caused by the effects of operator errors during

harsh environments caused by the accident. Valve alignment errors

transition between operating modes can be particularly important.

the

2. Equipment qualified for a harsh environment is likely to survive submersion

adverse ISLOCA temperature and humidity, but not the possible

caused by flooding.

or

3. Multiple system failures may result from the ISLOCA harsh environment to

flooding, depending on the size and location of the break in relation

of

affected equipment, the separation of redundant trains, and the effect

fire sprays on flooding.

essen-

4. ISLOCA recovery is limited by harsh environments, which may damageof loss

tial equipment thus complicating long-term cooling, and the rate

of reactor water outside the containment. If the water is not quickly has

replenished, an ISLOCA may lead to core damage, even after the leak

been isolated.

an ISLOCA

5. Symptom-based procedures may lead the operator to realize that to plant

has occurred. However, unless the emergency procedures refer

water, the operator may have

provisions for conserving and replenishing

difficulty managing the accident.

6. Most observed ISLOCA precursors have low risk consequences, primarily small

because of the presence of one or more of the following conditions:low

leak size, redundant means of detecting and isolating a leak, and

power or shutdown conditions.

Attachment 3 IN 92-36 May 7, 1992 Table 3. A Selected List of ISLOCA Reports and References

Identification Title or Subject Date

Potential for Common-Mode Failure of 10/04/90

IN 90-64 HPSI Pumps or Release of Reactor Coolant

Outside Containment During a LOCA

Inter-system Discharge of Reactor Coolant 01/29/90

IN 90-05 IN 89-73 Potential Overpressurization of Low 11/01/89 Pressure Systems

AIT Report An assessment of the 10/4/90 Braidwood 10/23/90

50-456/90-20 loss of reactor coolant inventory and

personnel contamination and injury

AIT Report An assessment of the 4/12/89 Pilgrim 05/08/89

50-293/89-80 overpressurization event, which occurred

during the conduct of the RCIC logic test

ISLOCA Program Inspection of the Waterford 09/14/90

Inspection

Report plant

50-382/90-200

ISLOCA Program Inspection of the Catawba 06/11/90

Inspection

Report plants

50-413,414/90-200

Inspection ISLOCA Program Inspection of the Davis 12/21/89 Report Besse plant

50-346/89-201 Audit Haddam Neck ISLOCA Audit Report: July 24 - 09/20/89 Report August 4, 1989, Enclosure to Memorandum

Docket No. 50-213 from Frank J. Congel, NRC, to

Steven A. Varga, NRC*

NUREG/CR-5745 Assessment for ISLOCA Risks - June 91 Draft Methodology and Application:

Combustion Engineering Plant

NUREG/CR-5744 Assessment for ISLOCA Risks - Feb 91 Draft Methodology and Application:

Westinghouse Four-Loop Ice Condenser Plant

NUREG/CR-5604 Assessment for ISLOCA Risks - Feb 91 Draft Methodology and Application: Babcock

and Wilcox Nuclear Power Station

NUREG/CR-5124 Interfacing Systems LOCA, Boiling Feb 89 Water Reactors

NUREG/CR-5102 Interfacing Systems LOCA, Pressurized Feb 89 Water Reactors

-A COpy OT this report is available in the NRC Public Document Room,

2120 L Street, N.W., Washington, DC.

Attachment 4 IN 92-36 May 7, 1992 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information Date of

Notice No. Subject Issuance Issued to

92-35 Higher Than Predicted Ero- 05/06/92 All holders of OLs or CPs

sion/Corrosion in Unisol- for nuclear power reactors.

able Reactor Coolant Pres- sure Boundary Piping Inside

Containment at A Boiling

Water Reactor

92-34 New Exposure Limits for 05/06/92 All licensees whose opera- Airborne Uranium and tions can cause airborne

Thorium concentrations of uranium

and thorium.

92-33 Increased Instrument 04/30/92 All holders of OLs or CPs

Response Time When for nuclear power reactors.

Pressure Dampening

Devices are Installed

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

Emergency Ventilation for nuclear power reactors.

Systems for Near-Site

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

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. 1 activity Calculations for nuclear power reactors.

OL = Operating License

CP = Construction Permit

IN 92-36 May 7, 1992 Table 1 presents the staff's observations from root cause analyses and plant

inspections. Table 2 presents insights gained from the ISLOCA PRAs.

The staff is completing its ISLOCA research program under Generic Issue 105,

"Intersystem Loss of Coolant Accidents in Light Water Reactors." Upon complet- ing this research, the staff may issue further generic correspondence to

licensees.

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.

Original Signed by

Charles E Rei

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical contacts: Kazimieras Campe, NRR

(301) 504-1092 Sammy Diab, RES

(301) 492-3914 Gary Burdick, RES

(301) 492-3812 Attachments:

1. Table 1. "Observed Plant Vulnerabilities to ISLOCA Precursors'

2. Table 2. "ISLOCA Risk Insights"

3. Table 3. "A Selected List of ISLOCA Reports and References"

4. List of Recently Issued NRC Information Notices

Document Name: IN 92-36

  • See previous concurrence.

C/OGCB:DOEA:NRR D/DOEA:NRR

  • CHBerlinger

04/24/92 RPB:ADM D/DSIR:RES C/RPSIB:DSIR:RES RPSIB:DSIR:RES C/EIB:DSIR:RES

  • TechEd *WMinners *KKniel *GBurdick *RLBaer

04/09/92 04/15/92 04/14/92 04/13/92 04/13/92 OGCB:DOEA:NRR SC/RAB:DREP:NRR C/RAB:DREP:NRR D/DREP:NRR EIB:DSIR:RES

  • CVHodge *KCampe *WBeckner *FCongel *SDiab

04/08/92 04/09/92 04/09/92 04/09/92 04/13/92

IN 92-XX

April xx, 1992 Table 1 presents the staff's observations from root cause analyses and plant

inspections. Table 2 presents insights gained from the ISLOCA PRAs.

The staff is completing its ISLOCA research program under Generic Issue 105,

"Intersystem Loss of Coolant Accidents in Light Water Reactors." Upon complet- ing this research, the staff may issue further generic correspondence to

licensees.

This information notice requires no speci fic action or written response. If

you have any questions about the informat ion 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: Kazimieras Campe, NRR

(301) 504-1092 Sammy Diab, RES

(301) 492-3914 Gary Burdick, RES

(301) 492-3812 Attachments:

1. Table 1. "Observed Plant Vulnerabilities to ISLOCA Precursors"

2. Table 2. "ISLOCA Risk Insights"

3. Table 3. "A Partial List of ISLOCA Reports and References"

4. List of Recently Issued NRC Information Notices

Document Name: ISLOCA REV 2 C/OGCB:DOEA:NRR D/D1DOEA: NRR

CHBerling~* fj, CER tossi l

04/21/92gq"' 04/

RPB:ADM D/D g kS CL SI R:RES RQ DSIR:RES C/EIB:D IRRES

TechEd J7Hh9q W" GB k RLBaerXiF'

04/ q/92 04/ 15~/ 92 04/A//92 04//3/92 04//3/92 OGCB:DOEA: RR SC/IRAB: REP:NRR C/RAB:DREP:IER D/DREP:N EIB:DSIR L>

CVHodge US9 KCaiimp WBeckner Xyt FCongel SDiab

04/od/92 04/ I9/9 04/A /92 04/9 /92 04/,3/92/


Retrieved from "https://kanterella.com/w/index.php?title=Information_Notice_1992-36,_Intersystem_LOCA_Outside_Containment&oldid=2200259"