Information Notice 1990-06, Potential for Loss of Shutdown Cooling While at Low Reactor Coolant Levels: 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 = 01/29/1990
| issue date = 01/29/1990
| title = Potential for Loss of Shutdown Cooling While at Low Reactor Coolant Levels
| title = Potential for Loss of Shutdown Cooling While at Low Reactor Coolant Levels
| 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 = 7
| page count = 7
| revision = 0
}}
}}
{{#Wiki_filter:UNITED STATESNUCLEAR REGULATORY COMMISSIONOFFICE OF NUCLEAR REACTOR REGULATIONWASHINGTON, D.C. 20555January 29, 1990NRC INFORMATION NOTICE NO. 90-06: POTENTIAL FOR LOSS OF SHUTDOWN COOLINGWHILE AT LOW REACTOR COOLANT LEVELS
{{#Wiki_filter:UNITED STATES
 
NUCLEAR REGULATORY COMMISSION
 
OFFICE OF NUCLEAR REACTOR REGULATION
 
WASHINGTON, D.C. 20555 January 29, 1990
                                                                      SHUTDOWN COOLING
 
NRC INFORMATION NOTICE NO. 90-06: POTENTIAL FOR LOSS OF COOLANT LEVELS
 
WHILE  AT   LOW REACTOR


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


==Purpose==
==Purpose==
:This information notice is intended to alert addressees to a potential problemaffecting the operability of the residual heat removal (RHR) system duringoperating conditions involving mid-loop operation. It is expected that re--cipients will review the information for applicability to their facilitiesand consider actions, as appropriate, to avoid similar problems. However,suggestions contained in this information notice do not constitute NRCrequirements; therefore, no specific action or written response is required.
:
                                                                      to a potential problem
 
This information notice is intended to alert addressees (RHR) system during
 
affecting the operability of the residual     heat removal
 
is expected that re- operating conditions involving mid-loop operation. It to their facilities
 
-cipients will review the information for applicability problems. However, and consider actions, as appropriate, to avoid similar constitute NRC
 
suggestions contained in this information notice do not
 
response is required.
 
requirements; therefore, no specific action or written


==Description of Circumstances==
==Description of Circumstances==
:On July 18, 1989, at Comanche Peak Unit 1, train 'Al of the residual heatremoval system was in operation prior to initial fuel loading. The airoperated RHR heat exchanger flow control valve (FCV) was being used tomaintain system flow below 2000 gpm. The reactor vessel water level wasbeing maintained slightly abpve the center line of the hot legs.The inverter supplying power to the controller for the FCV failed. The lossof power to the controller resulted in the FCV failing to its emergency corecooling system (ECCS) position of being fully open. The open valve causedan increase in system flow to 4400 gpm. This sudden, increased flow causedconditions where vortexing was expected at the suction of the RHR pipe con-nection to the RCS.The power supply for the controllers was manually transferred to an alternatesource and the FCV was throttled, thus terminating the event.Discussion:The FCV is manually throttled to maintain a desired rate of flow through theRHR heat exchanger. The heat exchanger flow rate is adjusted to control thetemperature of the water being returned to the vessel. Total system flow isregulated by throttling the heat exchanger bypass valve coincident with theadjustment of the FCV.001230175 Z ( (' D*1 IC,eo uachr IN 90-06January 29, 1990 During this event, there were no indications of pump air ingestion. However,the increased system flow corresponded to the rate at which vortexing hadbeen calculated to occur based on the existing RCS level. The licensee hadpreviously determined maximum permitted flow rates for various reduced levelsof the RCS to prevent the possibility of vortexing and air entrainment intothe RHR pump.Although RHR pump operation was never actually impaired, the potential existedfor air to be introduced to the pump's suction. This concern is exacerbated by* the fact that the heat exchanger FCVs for both trains of RHR are powered fromthe same inverter. Since the FCVs open fully on a loss of power, both trainsof RHR could become inoperable on a loss of power during mid-loop operation.(A loss of instrument air would also cause the FCVs to fail to the full openposition and could also result in the loss of both trains of the RHR system).During most modes of operation, having the FCVs go -fully open on loss ofpower or instrument air is not a safety concern because having the valvesfully open does not normally prevent the system from performing its safetyfunction. However, having the valves go fully open while at mid-loop couldresult in the loss of decay heat removal capability. This loss could persistuntil electrical power or instrument air is restored and air is vented fromthe RHR system.The licensee has revised procedures for mid-loop operation to require manuallypositioning the cold leg injection isolation valves to limit the maximum flowthrough the system, even with the FCVs fully open. This lineup will be usedwhenever the unit is at mid-loop and protects against the consequences offailure of either electrical power or instrument air.Several generic communications have been issued informing licensees of theconsequences of the loss of residual (decay) heat removal and the operatingconditions under which the probability of a loss increases; i.e., reducedinventory conditions. The most recent publications include Generic Letter(GL) No. 87-12, "Loss of Decay Heat Removal While the Reactor Coolant Systemis Partially Filled;" GL No. 88-17, *Loss of Decay Heat Removal;" NRC In-formation Notice (IN) 87-23, "Loss of Decay Heat Removal During Low ReactorCoolant Level Operation;" IN 88-36, 'Possible Sudden Loss of RCS InventoryDuring Low Coolant Level Operation;" and IN 89-67, "Loss of Residual HeatRemoval Caused by Accumulator Nitrogen Injection." The event describedabove introduces a subtle failure scenario which licensees may not haveconsidere IN 90-06January 29, 1990 This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contactone of the technical contacts listed below or the appropriate NRR project manager.Charles E. Rossi, irectorDivision of Operational Events AssessmentOffice of Nuclear Reactor RegulationTechnical Contacts: Nick Fields, NRR(301) 492-1173Steve Bitter, RIV(817) 897-1500
:
                                                                        the residual heat
 
On July 18, 1989, at Comanche Peak Unit 1, train 'Al ofloading. The air
 
removal system was in operation prior to   initial   fuel
 
being used to
 
operated RHR heat exchanger flow control valve (FCV) was water level was
 
maintain system flow below 2000 gpm.   The   reactor vessel
 
legs.
 
being maintained slightly abpve the center line of the hot
 
FCV failed. The loss
 
The inverter supplying power to the controller for the to its emergency core
 
of power to the controller resulted in the FCV failing             open valve caused
 
cooling system (ECCS) position of being fully open. The                   flow caused
 
an increase in system flow to 4400   gpm.   This   sudden,   increased
 
the RHR pipe con- conditions where vortexing was expected at the suction of
 
nection to the RCS.
 
to an alternate
 
The power supply for the controllers was manually transferred
 
terminating    the  event.
 
source and the FCV was throttled, thus
 
Discussion:
                                                                              flow through the
 
The FCV is manually throttled to maintain a desired rate of             to control the
 
RHR heat exchanger. The heat exchanger   flow   rate is adjusted
 
to   the vessel.      Total  system flow is
 
temperature of the water being returned                                       with the
 
regulated by throttling the heat exchanger bypass valve coincident
 
adjustment of the FCV.
 
001230175   Z                                                                   ((
                                                                                ' D*1 IC,
eo uachr
 
IN 90-06 January 29, 1990 During this event, there were no indications of pump air ingestion. However, the increased system flow corresponded to the rate at which vortexing had
 
been calculated to occur based on the existing RCS level. The licensee had
 
previously determined maximum permitted flow rates for various reduced levels
 
of the RCS to prevent the possibility of vortexing and air entrainment into
 
the RHR pump.
 
Although RHR pump operation was never actually impaired, the potential existed
 
for air to be introduced to the pump's suction. This concern is exacerbated by
 
* the fact that the heat exchanger FCVs for both trains of RHR are powered from
 
the same inverter. Since the FCVs open fully on a loss of power, both trains
 
of RHR could become inoperable on a loss of power during mid-loop operation.
 
(A loss of instrument air would also cause the FCVs to fail to the full open
 
position and could also result in the loss of both trains of the RHR system).
 
During most modes of operation, having the FCVs go -fully open on loss of
 
power or instrument air is not a safety concern because having the valves
 
fully open does not normally prevent the system from performing its safety
 
function. However, having the valves go fully open while at mid-loop could
 
result in the loss of decay heat removal capability. This loss could persist
 
until electrical power or instrument air is restored and air is vented from
 
the RHR system.
 
The licensee has revised procedures for mid-loop operation to require manually
 
positioning the cold leg injection isolation valves to limit the maximum flow
 
through the system, even with the FCVs fully open. This lineup will be used
 
whenever the unit is at mid-loop and protects against the consequences of
 
failure of either electrical power or instrument air.
 
Several generic communications have been issued informing licensees of the
 
consequences of the loss of residual (decay) heat removal and the operating
 
conditions under which the probability of a loss increases; i.e., reduced
 
inventory conditions. The most recent publications include Generic Letter
 
(GL) No. 87-12, "Loss of Decay Heat Removal While the Reactor Coolant System
 
is Partially Filled;" GL No. 88-17, *Loss of Decay Heat Removal;" NRC In- formation Notice (IN)87-23, "Loss of Decay Heat Removal During Low Reactor
 
Coolant Level Operation;" IN 88-36, 'Possible Sudden Loss of RCS Inventory
 
During Low Coolant Level Operation;" and IN 89-67, "Loss of Residual Heat
 
Removal Caused by Accumulator Nitrogen Injection." The event described
 
above introduces a subtle failure scenario which licensees may not have
 
considered.
 
IN 90-06 January 29, 1990 This information notice requires no specific action or written response. If
 
you have any questions about the information in this notice, please contact
 
one of the technical contacts listed below or the appropriate NRR project manager.
 
Charles E. Rossi,   irector
 
Division of Operational Events Assessment
 
Office of Nuclear Reactor Regulation
 
Technical Contacts: Nick Fields, NRR
 
(301) 492-1173 Steve Bitter, RIV
 
(817) 897-1500
Attachment:  List of Recently Issued NRC Information Notices
 
I
 
IN 90-06 January 29, 1990 During this event, there were no indications of pump air ingestion                                            However
 
the increased system flow enrraenan~nA n~                                          -~              neto.      Hwvr
 
Attachment    ~
                                    q    )                                    sx 90-06 Jasmary 2§ 1990
                                                                                Page I of I
 
LIST OF RECEITLT ISSUED
 
NIR INFORtAT1011 OTICES
 
JCW  --
                      lnfonation                                      Issuance Issued te
 
Notice No.      SubJect
 
90-05          Inter-System Discharge of      1/26/9O  All holders of ULs
 
Reactor Coelant                          or Ch for nuclear
 
power reactors.
 
90-04          Cracking of the Upper Shall-  1/26/90  All holders of OLs
 
to-Transition Cone Girth                or CPs.for Westinghouse.
 
Melds Is Steam Generators              designed and Combustion
 
Engineering-disigned
 
nuclear power reactors.
 
90-03            malfunction of Borg-Varner    1/23/90  All holders of OLs
 
SBlted Sonnet Check Valves              or CPs for uclewr
 
Causd by Failure of the                power reactors.
 
Swing Arm
 
90-02          Potential Degradation of        1/29D    All holders of OLs
 
Secondary Contaient                    or CPs for Slis.
 
90-01            lIportace of Proper            1/12/90  All holders of NRC
 
Response to Self-Identifted            materials licenses.
 
Violations by Licensees
 
89-90            Pressurizer Safety Valv        12/28/84 All holder of OMs
 
Lift Setpoint Shift                    or Ch for Pilb.
 
89-8            Event Notificatton            12/26/89 All holders of CLs
 
Workshents                              or en for nuclear
 
powerreactors.
 
89-88            Recent XRC-Sponsored          12/26189 All holders of Ots
 
Testing of motor-Operated              or CPsfor nutlear
 
Valves                                  poer reactors.
 
8647            Disablilg of Emergency        12/19189 All helders of OLs
 
Diesel Generators by                    or CVs for nuclear
 
Their Neutral Ground-Fault              power reactors.
 
Protection Circuitry
 
8945.            etalclad. Lou-Voltage        12/IS/19 All holders of OLs
 
Supp. 2        Power Circuit Dreakars                  or CPsfor nuclear
 
Refurbished with                        power reactors.
 
Substandard Parts
 
OL*OpitunceS                      -                        _
                        CV s Construction Permit
 
UNITED STATES
 
IPOSTAGE & FEES PAOID
 
NUCLEAR REGULATORY COMMISSION                                                                                              ISNiRC      1 WASHINGTON, D.C. 20555 OFFICIAL BUSINESS
 
PENALTY FOR PRIVATE USE. 8300
 
IN 90-06 January 29, 1990 This information notice requires no specific action or written response. If
 
you have any questions about the information in this notice, please contact
 
one of the technical contacts listed below or the appropriate NRR project manager.
 
Charles E. Rossi, Director
 
Division of Operational Events Assessment
 
Office of Nuclear Reactor Regulation
 
Technical Contacts:  Nick Fields, NRR
 
(301) 492-1173 Steve Bitter, RIV
 
(817) 897-1500
Attachment:  List of Recently Issued NRC Information Notices
 
*SEE PREVIOUS CONCURRENCE
 
EAB:NRR      TECH:EDITOR EAB:NRR    C:EAB:NRR    C:OGCB:NRR    NRR:SRXB
 
*NFields: db *BCalure    *DCFischer *CJHaughney *CHBerlinger *RJones
 
1/12/90      1/13/90    1/16/90    1/16/90      1/17/90      1/23/90
1/Z3'90
 
K)j                                V%2IN 90-
                                                        January , 1990 No specific action or written response is required by this information notice.
 
If you have any questions about this matter, please contact one of the technical
 
contacts listed below or the Regional Administrator of the appropriate regional
 
office.
 
Charles E. Rossi, Director
 
Division of Operational Events Assessment
 
Office of Nuclear Reactor Regulation
 
Technical Contacts:  Nick Fields (301) 492-1173 Steve Bitter (817) 897-1500
Attachment:  List of Recently Issued NRC Information Notices
 
*SEE PREVIOUS CONCURRENCE
 
EAB:NRR    TECH:EDITOR EAB:NRR C:EAB:NRR        C:OGCB:NRR    N R    B
 
*DCFischer  *CJHaughney* *CHBerlinger  RJV es
 
*NFields:db *BCalure
 
/ /90      / /90        / /90    / /90          / /90    I j:/90
D:DOEA:NRR
 
CERossi
 
/ /90
 
IN 90-
                                                                  January , 1990
                                                              %...Z'age 3 of 3 No specific action or written response is required by this
 
infornation notice. If you have any questions about this matter, please contact the technical contact listed below or the Regional
 
Administrator of the appropriate regional office.
 
Charles E. Rossi, Director
 
Division of Operational Events Assessment
 
Office of Nuclear Reactor Regulation
 
Technical Contacts:        Nick Fields (301) 492-1173 Steve Bitter (817) 897-1500
Attachment:    List of Recently Issued NRC Information Notices
 
C0Wvtn    Au t


===Attachment:===
AJF      VIU46x1 4fhire0rAtU rAI                      CV
List of Recently Issued NRC Information Notices IIN 90-06January 29, 1990 During this event, there were no indications of pump air ingestion Howeverthe increased system flow enrraenan~nA n~ -~ neto. HwvrAttachment ~q ) sx 90-06Jasmary 2§ 1990Page I of ILIST OF RECEITLT ISSUEDNIR INFORtAT1011 OTICESJCW --lnfonationNotice No.90-0590-04SubJectInter-System Discharge ofReactor CoelantIssuance1/26/9OCracking of the Upper Shall- 1/26/90to-Transition Cone GirthMelds Is Steam GeneratorsIssued teAll holders of ULsor Ch for nuclearpower reactors.All holders of OLsor CPs.for Westinghouse.designed and CombustionEngineering-disignednuclear power reactors.All holders of OLsor CPs for uclewrpower reactors.All holders of OLsor CPs for Slis.All holders of NRCmaterials licenses.90-03 malfunction of Borg-VarnerSBlted Sonnet Check ValvesCausd by Failure of theSwing Arm90-02 Potential Degradation ofSecondary Contaient90-01 lIportace of ProperResponse to Self-IdentiftedViolations by Licensees89-90 Pressurizer Safety ValvLift Setpoint Shift89-8 Event NotificattonWorkshents89-88 Recent XRC-SponsoredTesting of motor-OperatedValves8647 Disablilg of EmergencyDiesel Generators byTheir Neutral Ground-FaultProtection Circuitry8945. etalclad. Lou-VoltageSupp. 2 Power Circuit DreakarsRefurbished withSubstandard Parts1/23/901/29D1/12/9012/28/84 All holder of OMsor Ch for Pilb.12/26/89 All holders of CLsor en for nuclearpower reactors.12/26189 All holders of Otsor CPs for nutlearpoer reactors.12/19189 All helders of OLsor CVs for nuclearpower reactors.12/IS/1 9 All holders of OLsor CPs for nuclearpower reactors.OL*OpitunceS -_CV s Construction PermitUNITED STATESNUCLEAR REGULATORY COMMISSIONWASHINGTON, D.C. 20555OFFICIAL BUSINESSPENALTY FOR PRIVATE USE. 8300IPOSTAGE & FEES PAOIDISNiRC1 IN 90-06January 29, 1990 This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contactone of the technical contacts listed below or the appropriate NRR project manager.Charles E. Rossi, DirectorDivision of Operational Events AssessmentOffice of Nuclear Reactor RegulationTechnical Contacts:Nick Fields, NRR(301) 492-1173Steve Bitter, RIV(817) 897-1500


===Attachment:===
EAB:NRR   TECH:EDITOR         EAB:NRR   C:EAB:NRR C:OGCB:NRR D:DOEA:NRR
List of Recently Issued NRC Information Notices*SEE PREVIOUS CONCURRENCEEAB:NRR*NFields: db1/12/90TECH:EDITOR*BCalure1/13/90EAB:NRR C:EAB:NRR*DCFischer *CJHaughney1/16/90 1/16/90C:OGCB:NRR*CHBerlinger1/17/90NRR:SRXB*RJones1/23/901 /Z3'90 K)jV%2IN 90-January , 1990 No specific action or written response is required by this informationIf you have any questions about this matter, please contact one of thecontacts listed below or the Regional Administrator of the appropriateoffice.notice.technicalregionalCharles E. Rossi, DirectorDivision of Operational Events AssessmentOffice of Nuclear Reactor RegulationTechnical Contacts:Nick Fields (301) 492-1173Steve Bitter (817) 897-1500


===Attachment:===
NFields:db                     DCFischer CJHaughney CHBerlinger CERossi
List of Recently Issued NRC Information Notices*SEE PREVIOUS CONCURRENCEEAB:NRR*NFields:db/ /90D:DOEA:NRRCERossi/ /90TECH:EDITOR*BCalure/ /90EAB:NRR*DCFischer/ /90C:EAB:NRR*CJHaughney*/ /90C:OGCB:NRR*CHBerlinger/ /90N R BRJV esI j:/90 IN 90-January , 1990%...Z'age 3 of 3No specific action or written response is required by thisinfornation notice. If you have any questions about this matter,please contact the technical contact listed below or the RegionalAdministrator of the appropriate regional office.Charles E. Rossi, DirectorDivision of Operational Events AssessmentOffice of Nuclear Reactor RegulationTechnical Contacts:Nick Fields (301) 492-1173Steve Bitter (817) 897-1500List of Recently Issued NRC Information Notices


===Attachment:===
Jr //,/90    I /11/SQ         , /14/90    I /14/90  / 117/90        / /90}}
AJFEAB:NRRNFields:dbJr //,/90C0Wvtn Au tVIU46x1 4fhire0rAtU rAITECH:EDITOR EAB:NRRDCFischerI /11/SQ , /14/90C:EAB:NRRCJHaughneyI /14/90CVC:OGCB:NRRCHBerlinger/ 117/90D:DOEA:NRRCERossi/ /90}}


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

Latest revision as of 04:02, 24 November 2019

Potential for Loss of Shutdown Cooling While at Low Reactor Coolant Levels
ML031130325
Person / Time
Site: Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Mcguire, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Three Mile Island, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, 05000000, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant
Issue date: 01/29/1990
From: Rossi C
Office of Nuclear Reactor Regulation
To:
References
IN-90-006, NUDOCS 9001230175
Download: ML031130325 (7)
v • d • e


UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 January 29, 1990

SHUTDOWN COOLING

NRC INFORMATION NOTICE NO. 90-06: POTENTIAL FOR LOSS OF COOLANT LEVELS

WHILE AT LOW REACTOR

Addressees

nuclear power

All holders of operating licenses or construction permits for

reactors.

Purpose

to a potential problem

This information notice is intended to alert addressees (RHR) system during

affecting the operability of the residual heat removal

is expected that re- operating conditions involving mid-loop operation. It to their facilities

-cipients will review the information for applicability problems. However, and consider actions, as appropriate, to avoid similar constitute NRC

suggestions contained in this information notice do not

response is required.

requirements; therefore, no specific action or written

Description of Circumstances

the residual heat

On July 18, 1989, at Comanche Peak Unit 1, train 'Al ofloading. The air

removal system was in operation prior to initial fuel

being used to

operated RHR heat exchanger flow control valve (FCV) was water level was

maintain system flow below 2000 gpm. The reactor vessel

legs.

being maintained slightly abpve the center line of the hot

FCV failed. The loss

The inverter supplying power to the controller for the to its emergency core

of power to the controller resulted in the FCV failing open valve caused

cooling system (ECCS) position of being fully open. The flow caused

an increase in system flow to 4400 gpm. This sudden, increased

the RHR pipe con- conditions where vortexing was expected at the suction of

nection to the RCS.

to an alternate

The power supply for the controllers was manually transferred

terminating the event.

source and the FCV was throttled, thus

Discussion:

flow through the

The FCV is manually throttled to maintain a desired rate of to control the

RHR heat exchanger. The heat exchanger flow rate is adjusted

to the vessel. Total system flow is

temperature of the water being returned with the

regulated by throttling the heat exchanger bypass valve coincident

adjustment of the FCV.

001230175 Z ((

' D*1 IC,

eo uachr

IN 90-06 January 29, 1990 During this event, there were no indications of pump air ingestion. However, the increased system flow corresponded to the rate at which vortexing had

been calculated to occur based on the existing RCS level. The licensee had

previously determined maximum permitted flow rates for various reduced levels

of the RCS to prevent the possibility of vortexing and air entrainment into

the RHR pump.

Although RHR pump operation was never actually impaired, the potential existed

for air to be introduced to the pump's suction. This concern is exacerbated by

  • the fact that the heat exchanger FCVs for both trains of RHR are powered from

the same inverter. Since the FCVs open fully on a loss of power, both trains

of RHR could become inoperable on a loss of power during mid-loop operation.

(A loss of instrument air would also cause the FCVs to fail to the full open

position and could also result in the loss of both trains of the RHR system).

During most modes of operation, having the FCVs go -fully open on loss of

power or instrument air is not a safety concern because having the valves

fully open does not normally prevent the system from performing its safety

function. However, having the valves go fully open while at mid-loop could

result in the loss of decay heat removal capability. This loss could persist

until electrical power or instrument air is restored and air is vented from

the RHR system.

The licensee has revised procedures for mid-loop operation to require manually

positioning the cold leg injection isolation valves to limit the maximum flow

through the system, even with the FCVs fully open. This lineup will be used

whenever the unit is at mid-loop and protects against the consequences of

failure of either electrical power or instrument air.

Several generic communications have been issued informing licensees of the

consequences of the loss of residual (decay) heat removal and the operating

conditions under which the probability of a loss increases; i.e., reduced

inventory conditions. The most recent publications include Generic Letter

(GL) No. 87-12, "Loss of Decay Heat Removal While the Reactor Coolant System

is Partially Filled;" GL No. 88-17, *Loss of Decay Heat Removal;" NRC In- formation Notice (IN)87-23, "Loss of Decay Heat Removal During Low Reactor

Coolant Level Operation;" IN 88-36, 'Possible Sudden Loss of RCS Inventory

During Low Coolant Level Operation;" and IN 89-67, "Loss of Residual Heat

Removal Caused by Accumulator Nitrogen Injection." The event described

above introduces a subtle failure scenario which licensees may not have

considered.

IN 90-06 January 29, 1990 This information notice requires no specific action or written response. If

you have any questions about the information in this notice, please contact

one of the technical contacts listed below or the appropriate NRR project manager.

Charles E. Rossi, irector

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: Nick Fields, NRR

(301) 492-1173 Steve Bitter, RIV

(817) 897-1500

Attachment: List of Recently Issued NRC Information Notices

I

IN 90-06 January 29, 1990 During this event, there were no indications of pump air ingestion However

the increased system flow enrraenan~nA n~ -~ neto. Hwvr

Attachment ~

q ) sx 90-06 Jasmary 2§ 1990

Page I of I

LIST OF RECEITLT ISSUED

NIR INFORtAT1011 OTICES

JCW --

lnfonation Issuance Issued te

Notice No. SubJect

90-05 Inter-System Discharge of 1/26/9O All holders of ULs

Reactor Coelant or Ch for nuclear

power reactors.

90-04 Cracking of the Upper Shall- 1/26/90 All holders of OLs

to-Transition Cone Girth or CPs.for Westinghouse.

Melds Is Steam Generators designed and Combustion

Engineering-disigned

nuclear power reactors.

90-03 malfunction of Borg-Varner 1/23/90 All holders of OLs

SBlted Sonnet Check Valves or CPs for uclewr

Causd by Failure of the power reactors.

Swing Arm

90-02 Potential Degradation of 1/29D All holders of OLs

Secondary Contaient or CPs for Slis.

90-01 lIportace of Proper 1/12/90 All holders of NRC

Response to Self-Identifted materials licenses.

Violations by Licensees

89-90 Pressurizer Safety Valv 12/28/84 All holder of OMs

Lift Setpoint Shift or Ch for Pilb.

89-8 Event Notificatton 12/26/89 All holders of CLs

Workshents or en for nuclear

powerreactors.

89-88 Recent XRC-Sponsored 12/26189 All holders of Ots

Testing of motor-Operated or CPsfor nutlear

Valves poer reactors.

8647 Disablilg of Emergency 12/19189 All helders of OLs

Diesel Generators by or CVs for nuclear

Their Neutral Ground-Fault power reactors.

Protection Circuitry

8945. etalclad. Lou-Voltage 12/IS/19 All holders of OLs

Supp. 2 Power Circuit Dreakars or CPsfor nuclear

Refurbished with power reactors.

Substandard Parts

OL*OpitunceS - _

CV s Construction Permit

UNITED STATES

IPOSTAGE & FEES PAOID

NUCLEAR REGULATORY COMMISSION ISNiRC 1 WASHINGTON, D.C. 20555 OFFICIAL BUSINESS

PENALTY FOR PRIVATE USE. 8300

IN 90-06 January 29, 1990 This information notice requires no specific action or written response. If

you have any questions about the information in this notice, please contact

one of the technical contacts listed below or the appropriate NRR project manager.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: Nick Fields, NRR

(301) 492-1173 Steve Bitter, RIV

(817) 897-1500

Attachment: List of Recently Issued NRC Information Notices

  • SEE PREVIOUS CONCURRENCE

EAB:NRR TECH:EDITOR EAB:NRR C:EAB:NRR C:OGCB:NRR NRR:SRXB

  • NFields: db *BCalure *DCFischer *CJHaughney *CHBerlinger *RJones

1/12/90 1/13/90 1/16/90 1/16/90 1/17/90 1/23/90

1/Z3'90

K)j V%2IN 90-

January , 1990 No specific action or written response is required by this information notice.

If you have any questions about this matter, please contact one of the technical

contacts listed below or the Regional Administrator of the appropriate regional

office.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: Nick Fields (301) 492-1173 Steve Bitter (817) 897-1500

Attachment: List of Recently Issued NRC Information Notices

  • SEE PREVIOUS CONCURRENCE

EAB:NRR TECH:EDITOR EAB:NRR C:EAB:NRR C:OGCB:NRR N R B

  • DCFischer *CJHaughney* *CHBerlinger RJV es
  • NFields:db *BCalure

/ /90 / /90 / /90 / /90 / /90 I j:/90

D:DOEA:NRR

CERossi

/ /90

IN 90-

January , 1990

%...Z'age 3 of 3 No specific action or written response is required by this

infornation notice. If you have any questions about this matter, please contact the technical contact listed below or the Regional

Administrator of the appropriate regional office.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: Nick Fields (301) 492-1173 Steve Bitter (817) 897-1500

Attachment: List of Recently Issued NRC Information Notices

C0Wvtn Au t

AJF VIU46x1 4fhire0rAtU rAI CV

EAB:NRR TECH:EDITOR EAB:NRR C:EAB:NRR C:OGCB:NRR D:DOEA:NRR

NFields:db DCFischer CJHaughney CHBerlinger CERossi

Jr //,/90 I /11/SQ , /14/90 I /14/90 / 117/90 / /90


Retrieved from "https://kanterella.com/w/index.php?title=Information_Notice_1990-06,_Potential_for_Loss_of_Shutdown_Cooling_While_at_Low_Reactor_Coolant_Levels&oldid=2200907"