Information Notice 1993-45, Degradation of Shutdown Cooling System Performance: Difference between revisions

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| issue date = 06/16/1993
| issue date = 06/16/1993
| title = Degradation of Shutdown Cooling System Performance
| title = Degradation of Shutdown Cooling System Performance
| author name = Grimes B K
| author name = Grimes B
| author affiliation = NRC/NRR
| author affiliation = NRC/NRR
| addressee name =  
| addressee name =  
Line 14: Line 14:
| page count = 9
| page count = 9
}}
}}
{{#Wiki_filter:UNITED STATES NUCLEAR REGULATORY
{{#Wiki_filter:UNITED STATES


COMMISSION
NUCLEAR REGULATORY COMMISSION


===OFFICE OF NUCLEAR REACTOR REGULATION===
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555 June 16, 1993 NRC INFORMATION


NOTICE 93-45: DEGRADATION
WASHINGTON, D.C. 20555 June 16, 1993 NRC INFORMATION NOTICE 93-45:   DEGRADATION OF SHUTDOWN COOLING


===OF SHUTDOWN COOLING SYSTEM PERFORMANCE===
SYSTEM PERFORMANCE


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


licenses or construction
reactors.
 
permits for nuclear power reactors.


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


Commission (NRC) is issuing this information
notice to alert addressees to degradation of shutdown cooling system


notice to alert addressees
performance at the Oyster Creek Nuclear Generating Station resulting from


to degradation
inadequate operating procedures. It is expected that recipients will review


of shutdown cooling system performance
the information for applicability to their facilities and consider actions, as


at the Oyster Creek Nuclear Generating
appropriate, to avoid similar problems. However, suggestions contained in


Station resulting
this information notice are not NRC requirements; therefore, no specific


from inadequate
action or written response is required.


operating
==Description of Circumstances==
On January 23, 1993, the Oyster Creek Nuclear Generating Station was in day 57 of the 14R refueling outage. The plant was in a normal cold-shutdown


procedures.
condition with the primary containment open and the reactor coolant system at


It is expected that recipients
about 43' C [110* F]. One reactor recirculation loop was in service, one


will review the information
recirculation loop was open, and the remaining three recirculation loops were


for applicability
either idled or isolated. Two shutdown cooling loops were operating with a


to their facilities
combined flow rate of 11,735 liters per minute 13,100 gpm].


and consider actions, as appropriate, to avoid similar problems.
In order to support the planned activities, the licensee elected to secure


However, suggestions
operation of all recirculation pumps and lower reactor water level. This


contained
configuration would allow completion, in parallel, of recirculation pump


in this information
maintenance activities and main steam isolation valve local leak rate testing.


notice are not NRC requirements;
When the operators lowered the reactor water level to approximately 419 cm
therefore, no specific action or written response is required.Description


of Circumstances
(165 inches] above the top of active fuel and secured the running.


On January 23, 1993, the Oyster Creek Nuclear Generating
recirculation pump, the shutdown cooling water took the least resistance path


Station was in day 57 of the 14R refueling
through the open recirculation loop, and the majority of flow bypassed the


outage. The plant was in a normal cold-shutdown
core (see Attachment 1). During the time that the planned activities were in


condition
progress, plant personnel did not realize that shutdown cooling system


with the primary containment
performance was degraded, allowing unmonitored heatup of the reactor core.


open and the reactor coolant system at about 43' C [110* F]. One reactor recirculation
On January 25, 1993, after completing the main steam isolation valve local


loop was in service, one recirculation
leak rate testing, an operations engineer discovered that the reactor vessel


loop was open, and the remaining
metal temperature was about 109C 1228F] at the mid-vessel point. Several


three recirculation
9306090036      PDI      I.E        No*[ct      3-.            oj58
  . .          P                                                      'v1\


loops were either idled or isolated.
IN 93-45 June 16, 1993 C [212 F] were not


Two shutdown cooling loops were operating
Technical Specifications prerequisites for exceeding 100.                    integrity.


with a combined flow rate of 11,735 liters per minute 13,100 gpm].In order to support the planned activities, the licensee elected to secure operation
met, including the requirement to establish    primary    containment


of all recirculation
measures    to  reduce      reactor    coolant


pumps and lower reactor water level. This configuration
After discovery, operators took immediate                          two    operating


would allow completion, in parallel, of recirculation
system water temperature by first  maximizing  flow  in the


pump maintenance
cooling loop in


activities
shutdown cooling loops and then placing a third shutdown              to approximately


and main steam isolation
service. Additionally, the reactor water level was raised  a  recirculation        pump was


valve local leak rate testing.When the operators
508 cm [200 inches] above the   top of  active  fuel  and


lowered the reactor water level to approximately
started.


419 cm (165 inches] above the top of active fuel and secured the running.recirculation
conditions


pump, the shutdown cooling water took the least resistance
The immediate cause of the event was determined to be plant cooling operating


path through the open recirculation
established by a temporary procedure  change  to  the shutdown


loop, and the majority of flow bypassed the core (see Attachment
through the reactor


1). During the time that the planned activities
procedure that failed to provide sufficient forced flow procedure            change had


were in progress, plant personnel
core to prevent thermal stratification.    The  temporary


did not realize that shutdown cooling system performance
pumps


was degraded, allowing unmonitored
been implemented to allow shutdown operations with all recirculationlevel at      which


heatup of the reactor core.On January 25, 1993, after completing
secured and the nominal reactor water level less than the (approximately 470 cm


the main steam isolation
spillover from the core region  to  the annulus  is assured


valve local leak rate testing, an operations
been developed


engineer discovered
[185 inches] above the top of active fuel). The change had        a requirement (stated


that the reactor vessel metal temperature
from a draft engineering evaluation, but did not includeshutdown cooling flow


was about 109C 1228F] at the mid-vessel
in the body of the evaluation) to maintain a specified                    shutdown cooling


point. Several 9306090036 PDI I.E No*[ct 3-. oj58 P ..'v1\
of 22,712 liters per minute [6,000 gpm]. Instead, the usual                    which, due
IN 93-45 June 16, 1993 Technical


Specifications
flow of about 11,735 liters per minute [3,100 gpm] was maintainedheatup.


prerequisites
to the specified configuration, allowed the inadvertent reactor


for exceeding
and NRC


100. C [212 F] were not met, including
Further details can be found in Licensee Event Report 50-219/93-002 Augmented Inspection Team Inspection Report No. 50-219/93-80.


the requirement
Discussion
 
to establish
 
primary containment
 
integrity.
 
After discovery, operators
 
took immediate
 
measures to reduce reactor coolant system water temperature
 
by first maximizing
 
flow in the two operating shutdown cooling loops and then placing a third shutdown cooling loop in service. Additionally, the reactor water level was raised to approximately


508 cm [200 inches] above the top of active fuel and a recirculation
change


pump was started.The immediate
This event at Oyster Creek indicated that the temporary procedure  review    process    did


cause of the event was determined
represented a significant procedure revision and that        the


to be plant conditions
was    implemented.        The


established
not identify deficiencies in the procedure before it                  engineering


by a temporary
temporary procedure change had been developed from a draft in operation would


procedure
evaluation which concluded that two shutdown cooling        loops


change to the shutdown cooling operating procedure
of the


that failed to provide sufficient
adequately cool the core. An additional assumption in the body                      at its


forced flow through the reactor core to prevent thermal stratification.
evaluation was that each loop of shutdown cooling      would    be  operating


The temporary
gpm],    for    a total    flow


procedure
design flow rate of 11,356 liters per minute [3,000                        would  be


change had been implemented
rate of 22,712 liters per minute [6,000 gpm]. This        flow    rate


to allow shutdown operations
at the


with all recirculation
adequate to induce spillover from the core region to the annulus         that  implemented
 
pumps secured and the nominal reactor water level less than the level at which spillover
 
from the core region to the annulus is assured (approximately
 
470 cm[185 inches] above the top of active fuel). The change had been developed from a draft engineering
 
evaluation, but did not include a requirement (stated in the body of the evaluation)
to maintain a specified
 
shutdown cooling flow of 22,712 liters per minute [6,000 gpm]. Instead, the usual shutdown cooling flow of about 11,735 liters per minute [3,100 gpm] was maintained
 
which, due to the specified
 
configuration, allowed the inadvertent
 
reactor heatup.Further details can be found in Licensee Event Report 50-219/93-002 and NRC Augmented
 
Inspection
 
Team Inspection
 
Report No. 50-219/93-80.
 
Discussion


This event at Oyster Creek indicated
reduced nominal water level. The temporary procedure        change


that the temporary
flow    rate    of  22,712 the engineering evaluation did not require a minimum                                the


procedure
operators      following


change represented
liters per minute [6,000 gpm]. As a result, the                              loops    in


a significant
deficient temporary procedure change placed two    shutdown      cooling


procedure
cooling      water    to  the


revision and that the review process did not identify deficiencies
operation, but did not provide sufficient shutdown                  addition, the


in the procedure
reactor core to maintain reactor vessel temperatures. In                  for monitoring


before it was implemented.
temporary procedure change contained no  provision    or  guidance


The temporary
heat  was    being    adequately      removed


procedure
available instruments to ensure that decay


change had been developed
from the reactor core.


from a draft engineering
the


evaluation
As part of the licensee corrective actions, the licensee reviewedchanges and


which concluded
effectiveness of its safety review process  concerning      temporary


that two shutdown cooling loops in operation
who


would adequately
provided training on the subject of this event to all site personnel


cool the core. An additional
perform technical and safety reviews.


assumption
IN 93-45 June 16, 1993 This information notice requires no specific action or written response. If


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


was that each loop of shutdown cooling would be operating
one of the technical contacts listed below or the appropriate Offic of


at its design flow rate of 11,356 liters per minute [3,000 gpm], for a total flow rate of 22,712 liters per minute [6,000 gpm]. This flow rate would be adequate to induce spillover
Nuclear Reactor Regulation (NRR) project manager.


from the core region to the annulus at the reduced nominal water level. The temporary
Brian K. Grimes, Director


procedure
Division of Operating Reactor


change that implemented
Support


the engineering
Office of Nuclear Reactor Regulation


evaluation
Technical contacts:  James S. Stewart, RI


did not require a minimum flow rate of 22,712 liters per minute [6,000 gpm]. As a result, the operators
(215) 337-5240
                    Peter C. Wen, NRR


following
(301) 504-2832 Attachments:
1. Figure 1, *Oyster Creek Shutdown Cooling System


the deficient
Flow With Open Recirculation Loop"
2. List of Recently Issued NRC Information Notices


temporary
K. /                              I'l I


procedure
Attachment 1
                                                                        1iK 93-45 June 16, 1993 Steam Flow  *-
              4- Open Recirculation


change placed two shutdown cooling loops in operation, but did not provide sufficient
TORecirculation                                              Loop


shutdown cooling water to the reactor core to maintain reactor vessel temperatures.
#    ~Loop


In addition, the temporary
Shutdown Cooling


procedure
System


change contained
(3 Cooling Loops)
                                        Figure 1 Oyster Creek Shutdown Cooling System Flow With Open Recirculation Loop


no provision
I


or guidance for monitoring
Attachment 2 IN 93-45 June 16, 1993 LIST OF RECENTLY ISSUED


available
NRC INFORMATION NOTICES


instruments
Information                                      Date of


to ensure that decay heat was being adequately
Notice No.                Subject                Issuance  Issued to


removed from the reactor core.As part of the licensee corrective
93-44            Operational Challenges          06/15/93  All holders of OLs or CPs


actions, the licensee reviewed the effectiveness
During A Dual-Unit                        for nuclear power reactors.


of its safety review process concerning
Transient


temporary
93-43            Use of Inappropriate            06/10/93  All holders of OLs or CPs


changes and provided training on the subject of this event to all site personnel
Lubrication Oils in                        for nuclear power reactors.


who perform technical
Safety-Related Applications


and safety reviews.
93-42            Failure of Anti-Rotation        06/09/93  All holders of OLs or CPs


IN 93-45 June 16, 1993 This information
Keys in Motor-Operated                      for nuclear power reactors.


notice requires no specific action or written response.
Valves Manufactured by


If you have any questions
Velan


about the information
93-41            One Hour Fire Endurance          05/28/93  All holders of OLs or CPs


in this notice, please contact one of the technical
Test Results for Thermal                    for nuclear power reactors.


contacts listed below or the appropriate
Ceramics Kaowool, 3M


Offic of Nuclear Reactor Regulation (NRR) project manager.Brian K. Grimes, Director Division of Operating
Company FS-195 and


===Reactor Support Office of Nuclear Reactor Regulation===
3M Company Interam E-50
Technical
                  Barrier Systems


contacts:
93-40            Fire Endurance Test            05/26/93  All holders of OLs or CPs
James S. Stewart, RI (215) 337-5240 Peter C. Wen, NRR (301) 504-2832 Attachments:
1. Figure 1, *Oyster Creek Shutdown Cooling System Flow With Open Recirculation


Loop" 2. List of Recently Issued NRC Information
Results for Thermal                        for nuclear power reactors.


Notices
Ceramics FP-60 Fire


K. /I'l I Steam Flow *-4-TO Recirculation
Barrier Material


# ~Loop Shutdown Cooling System (3 Cooling Loops)Figure 1 Attachment
,93-39            Radiation Beams from            05/25/93  All holders of OLs or CPs


1 1iK 93-45 June 16, 1993 Open Recirculation
Power Reactor Biolog-                     for nuclear power reactors.


Loop Oyster Creek Shutdown Cooling System Flow With Open Recirculation
ical Shields


Loop
93-38            Inadequate Testing of          05/24/93  All holders of OLs or CPs


I Attachment
Engineered Safety                          for nuclear power reactors.


2 IN 93-45 June 16, 1993 LIST OF RECENTLY ISSUED NRC INFORMATION
Features Actuation


NOTICES Information
System


Date of Notice No. Subject Issuance Issued to 93-44 93-43 93-42 Operational
93-37            Eyebolts with Indeter-         05/19/93   All holders of OLs or CPs


Challenges
minate Properties In-                      for nuclear power reactors.


During A Dual-Unit Transient Use of Inappropriate
stalled in Limitorque


Lubrication
Valve Operator Housing


Oils in Safety-Related
Covers


===Applications===
0L - Operating License
Failure of Anti-Rotation


Keys in Motor-Operated
CP - Construction Permit


Valves Manufactured
IN 93-45 June 16, 1993 This information notice requires no specific action or written response. If


by Velan 06/15/93 06/10/93 06/09/93 All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for nuclear power reactors.93-41 One Hour Fire Endurance Test Results for Thermal Ceramics Kaowool, 3M Company FS-195 and 3M Company Interam E-50 Barrier Systems 05/28/93 All holders for nuclear of OLs or CPs power reactors.93-40 ,93-39 93-38 Fire Endurance
you have any questions about the information in this notice, please contact


Test Results for Thermal Ceramics FP-60 Fire Barrier Material Radiation
one of the technical contacts listed below or the appropriate Office of


Beams from Power Reactor Biolog-ical Shields Inadequate
Nuclear Reactor Regulation (NRR) project manager.


Testing of Engineered
Original !1gnd by


Safety Features Actuation System 05/26/93 05/25/93 05/24/93 All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for nuclear power reactors.All holders for nuclear of OLs or CPs power reactors.93-37 Eyebolts with Indeter-minate Properties
Brian K. Gdmeg


In-stalled in Limitorque
Brian K. Grimes, Director


Valve Operator Housing Covers 05/19/93 All holders of OLs or CPs for nuclear power reactors.0L -Operating
Division of Operating Reactor Support


License CP -Construction
Office of Nuclear Reactor Regulation


Permit
Technical contacts:        James S. Stewart, RI


IN 93-45 June 16, 1993 This information
(215) 337-5240
                          Peter C. Wen, NRR


notice requires no specific action or written response.
(301) 504-283],
Attachments:    6
1. Figure 1, "Oyster Creek Shutdown Cooling System


If you have any questions
Flow With Open Recirculation Loop'
2. List of Recently Issued NRC Information Notices


about the information
*rFF  pRmVrnus CONCURRFNCF


in this notice, please contact one of the technical
OFFICE  *OGCB:DORS      *DRS:RI        **SC:DRS:RI      **BC:DRS:RI    **D:DRS:RI


contacts listed below or the appropriate
NAME      PCWen/vsb      JSStewart      PKEapen          JPDurr        MWHodges


Office of Nuclear Reactor Regulation (NRR) project manager.Original !1gnd by Brian K. Gdmeg Brian K. Grimes, Director Division of Operating
DATE      04/29/93        05/03/93      03/19/93        03/19/A3      .03/19/93
                _______-    _                                    .


===Reactor Support Office of Nuclear Reactor Regulation===
*Tech Ed.  I *C:OGCB:DORS--    *D:DSSA:NRR
Technical


contacts: James S. Stewart, RI (215) 337-5240 Peter C. Wen, NRR (301) 504-283], Attachments:
RSanders    IGHMarcus          ACThadani
6 1. Figure 1, "Oyster Creek Shutdown Cooling System Flow With Open Recirculation


Loop'2. List of Recently Issued NRC Information
04/29/93      05/10            05/24/93
                                      **SEE MEMO FROM M.. HODGES TO B.K. GRIMES


Notices*rFF pRmVrnus CONCURRFNCF
=
                              .


OFFICE *OGCB:DORS
DOCUMENT  NAME:     93-45.IN


*DRS:RI **SC:DRS:RI
DATED 3/19/93 PM (A. Dromerick), EAB (J. Carter) and AIT


**BC:DRS:RI
Team Leader (J. Beall) were consulted during


**D:DRS:RI
the development of this IN.


NAME PCWen/vsb
IN 93-XX


JSStewart
May xx, 1993 This information notice requires no specific action or written response. If


PKEapen JPDurr MWHodges DATE 04/29/93 05/03/93 03/19/93 03/19/A3 .03/19/93_______- _ .*Tech Ed. I *C:OGCB:DORS--
you have any questions about the information in this notice, please contact
*D:DSSA:NRR


RSanders I GHMarcus ACThadani 04/29/93 05/10 05/24/93.=DOCUMENT NAME: 93-45.IN**SEE MEMO FROM M.. HODGES TO B.K. GRIMES DATED 3/19/93 PM (A. Dromerick), EAB (J. Carter) and AIT Team Leader (J. Beall) were consulted
one of the technical contacts listed below or the appropriate Office of


during the development
Nuclear Reactor Regulation (NRR) project manager.


of this IN.
Brian K. Grimes, Director


IN 93-XX May xx, 1993 This information
Division of Operating Reactor Support


notice requires no specific action or written response.
Office of Nuclear Reactor Regulation


If you have any questions
Technical contacts:          James S. Stewart, Region I


about the information
(215) 337-5240
                              Peter C. Wen, NRR


in this notice, please contact one of the technical
(301) 504-2832 Attachments:
1. Oyster Creek Shutdown Cooling System Flow With Open Recirculation Loop


contacts listed below or the appropriate
2. List of Recently Issued NRC Information Notices


Office of Nuclear Reactor Regulation (NRR) project manager.Brian K. Grimes, Director Division of Operating
*SEE PREVIOUS CONCURRENCE


===Reactor Support Office of Nuclear Reactor Regulation===
OFFICE    *OGCB:DORS          *DRS:RI        **SC:DRS:RI  **BC:DRS:RI  **D:DRS:RI
Technical


contacts: James S. Stewart, Region I (215) 337-5240 Peter C. Wen, NRR (301) 504-2832 Attachments:
NAME      PCWen/vsb          JSStewart      PKEapen      JPDurr        MWHodges
1. Oyster Creek Shutdown Cooling System Flow With Open Recirculation


Loop 2. List of Recently Issued NRC Information
DATE      l04/29/93        l05/03/93        I 03/19/93    l 03/19/93    l03/19/93
  *Tech Ed.     *C:OGCB:DORS          D:DORS:NRR


Notices*SEE PREVIOUS CONCURRENCE
IRSanders      GHMarcus              BKGrimes


OFFICE *OGCB:DORS
04/29/93 _ 05/10/93                ;05/    /93      4 xk)
    onf~~~l                oI~tsPIm


*DRS:RI **SC:DRS:RI
- - - - 1F


**BC:DRS:RI
UULUIMNI NAMI:    UIIrMUN .PW)          **SEE MEMO FROM M.W. HODGES TO B.K. GRIMES


**D:DRS:RI
DATED 3/19/93 PM (A. Dromerick), EAB (J. Carter) and AIT


NAME PCWen/vsb
Team Leader (J. Beall) were consulted during


JSStewart
the development of this IN.


PKEapen JPDurr MWHodges DATE l04/29/93 l05/03/93 I 03/19/93 l 03/19/93 l03/19/93*Tech Ed.*C:OGCB:DORS
530
                                                            AV 'I/tllos


D:DORS:NRR
ACiwAt  #
                                        fA);mli      v-


I RSanders GHMarcus 04/29/93 _ 05/10/93 ;onf~~~l ----1F o I~tsPIm BKGrimes UULUIMNI NAMI: UIIrMUN .PW)05/ /93 4 xk)**SEE MEMO FROM M.W. HODGES TO B.K. GRIMES DATED 3/19/93 PM (A. Dromerick), EAB (J. Carter) and AIT Team Leader (J. Beall) were consulted
IN 93-XX


during the development
May xx, 1993 This information notice requires no specific action or written response. If


of this IN.530 ACiwAt #f A);mli v-AV'I/tllos
you have any questions about the information in this notice, please contact


IN 93-XX May xx, 1993 This information
one of the technical contacts listed below or the appropriate Office of


notice requires no specific action or written response.
Nuclear Reactor Regulation (NRR) project manager.


If you have any questions
Brian K. Grimes, Director


about the information
Division of Operating Reactor Support


in this notice, please contact one of the technical
Office of Nuclear Reactor Regulation


contacts listed below or the appropriate
Technical contacts:    James S. Stewart, Region I


Office of Nuclear Reactor Regulation (NRR) project manager.Brian K. Grimes, Director Division of Operating
(215) 337-5240
                        Peter C. Wen, NRR


===Reactor Support Office of Nuclear Reactor Regulation===
(301) 504-2832 Attachments:
Technical
1.    Oyster Creek Shutdown Cooling System Flow With Open Recirculation Loop


contacts: James S. Stewart, Region I (215) 337-5240 Peter C. Wen, NRR (301) 504-2832 Attachments:
2.     List of Recently Issued NRC Information Notices
1.2.Oyster Creek Shutdown Cooling System Flow With Open Recirculation


Loop List of Recently Issued NRC Information
*SEE PREVIOUS CONCURRENCE .


Notices*SEE PREVIOUS CONCURRENCE
OFFICE  *OGCB:DORS    DRS:RI        SC:DRS:RI    BC:DRS:RI      D:DRS:RI


.OFFICE *OGCB:DORS
NAME    PCWen/vsb    4SStewart      PKEapen      JPDurr          MWHodges


DRS:RI SC:DRS:RI
DATE    04/29/93      05/3,0 Cal    P/1/93        0/    l/9 3    I__ 1_/93_J


BC:DRS:RI
*Tech Ed.    C:OGCB:DORS      D:DORS:NRR        4xx %E memo          MYS


D:DRS:RI NAME PCWen/vsb
Fizz  144 RSanders    GHMarcus Ci~l BKGrimes                    44 1/1 A/3
  04/29/93    05/ 1q993      105/  /93 DOUUMENT NAME:   OCTPCIN.PW                      PA (A 'rolnerlk&) , 1      (. Covte).    t


4SStewart
AlT  Team Leader (J. &3eA.A)  LxQe cuAJX4A


PKEapen JPDurr MWHodges DATE 04/29/93 05/3,0 Cal P/1/93 0/ l/9 3 I__ 1_/93_J*Tech Ed.C:OGCB:DORS
Alxrzrl t.     4JeLt"e'4  . tk& z4BJ


D:DORS:NRR
IN 93-XX


4xx %E memo Fizz MYS 144 RSanders GHMarcus Ci~l BKGrimes 04/29/93 05/ 1q 9 93 1 05/ /93 44 1/1 A/ 3 DOUUMENT NAME: OCTPCIN.PW
May xx, 1993 Page 2 of


PA (A 'rolnerlk&) , 1 (. Covte). t AlT Team Leader (J. &3eA.A) LxQe cuAJX4A Alxrzrl t. 4JeLt"e'4
This information notice requires no specific action or written response. If
.tk& z4 BJ


IN 93-XX May xx, 1993 Page 2 of This information
you have any questions about the information in this notice, please contact


notice requires no specific action or written response.
one of the technical contacts listed below or the appropriate Office of


If you have any questions
Nuclear Reactor Regulation (NRR) project manager.


about the information
Brian K. Grimes, Director


in this notice, please contact one of the technical
Division of Operating Reactor Support


contacts listed below or the appropriate
Office of Nuclear Reactor Regulation


Office of Nuclear Reactor Regulation (NRR) project manager.Brian K. Grimes, Director Division of Operating
Technical contacts:          James S. Stewart, Region I


===Reactor Support Office of Nuclear Reactor Regulation===
(215) 337-5240
Technical
                                Peter C. Wen, NRR


contacts: James S. Stewart, Region I (215) 337-5240 Peter (301)C. Wen, NRR 504-2832 Attachments:
(301) 504-2832 Attachments:
1.2.Oyster Creek Shutdown Cooling System Flow With Open Recirculation
1.     Oyster Creek Shutdown Cooling System Flow With Open Recirculation Loop


Loop List of Recently Issued NRC Information
2.      List of Recently Issued NRC Information Notices


Notices OFFICE OBORS DRS:RI SC:DRS:RI
OFFICE       OBORS               DRS:RI         SC:DRS:RI    BC:DRS:RI    D:DRS:RI


BC:DRS:RI
NAME        PCWen/vsb          JSStewart        PKEapen      JPDurr        MWHodges


D:DRS:RI NAME PCWen/vsb
DATE              _/aq/93_    05/    /93      05/  /93    05/  /93  105/    /93 Tech Ed.      C:OGCB:DORS            D: DORS:NRRI


JSStewart
flU"AJA& GHMarcus                    BKGrimes


PKEapen JPDurr MWHodges DATE _/aq/93_ 05/ /93 05/ /93 05/ /93 105/ /93 Tech Ed.C:OGCB:DORS
ON/.11/93       05/   /93             05/   /93
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D: DORS:NR RI flU"AJA& GHMarcus BKGrimes ON/.11/93
UUUMt Ii NAMt:       ULIrMLIN.fW}}
05/ /93 05/ /93%^rrlT scur -rnT -ab UUUMt Ii NAMt: ULIrMLIN.fW}}


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

Latest revision as of 04:21, 24 November 2019

Degradation of Shutdown Cooling System Performance
ML031070480
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: 06/16/1993
From: Grimes B
Office of Nuclear Reactor Regulation
To:
References
IN-93-045, NUDOCS 9306090036
Download: ML031070480 (9)
v • d • e


UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 June 16, 1993 NRC INFORMATION NOTICE 93-45: DEGRADATION OF SHUTDOWN COOLING

SYSTEM PERFORMANCE

Addressees

All holders of operating licenses or construction permits for nuclear power

reactors.

Purpose

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

notice to alert addressees to degradation of shutdown cooling system

performance at the Oyster Creek Nuclear Generating Station resulting from

inadequate operating procedures. It is expected that recipients will review

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

appropriate, to avoid similar problems. However, suggestions contained in

this information notice are not NRC requirements; therefore, no specific

action or written response is required.

Description of Circumstances

On January 23, 1993, the Oyster Creek Nuclear Generating Station was in day 57 of the 14R refueling outage. The plant was in a normal cold-shutdown

condition with the primary containment open and the reactor coolant system at

about 43' C [110* F]. One reactor recirculation loop was in service, one

recirculation loop was open, and the remaining three recirculation loops were

either idled or isolated. Two shutdown cooling loops were operating with a

combined flow rate of 11,735 liters per minute 13,100 gpm].

In order to support the planned activities, the licensee elected to secure

operation of all recirculation pumps and lower reactor water level. This

configuration would allow completion, in parallel, of recirculation pump

maintenance activities and main steam isolation valve local leak rate testing.

When the operators lowered the reactor water level to approximately 419 cm

(165 inches] above the top of active fuel and secured the running.

recirculation pump, the shutdown cooling water took the least resistance path

through the open recirculation loop, and the majority of flow bypassed the

core (see Attachment 1). During the time that the planned activities were in

progress, plant personnel did not realize that shutdown cooling system

performance was degraded, allowing unmonitored heatup of the reactor core.

On January 25, 1993, after completing the main steam isolation valve local

leak rate testing, an operations engineer discovered that the reactor vessel

metal temperature was about 109C 1228F] at the mid-vessel point. Several

9306090036 PDI I.E No*[ct 3-. oj58

. . P 'v1\

IN 93-45 June 16, 1993 C [212 F] were not

Technical Specifications prerequisites for exceeding 100. integrity.

met, including the requirement to establish primary containment

measures to reduce reactor coolant

After discovery, operators took immediate two operating

system water temperature by first maximizing flow in the

cooling loop in

shutdown cooling loops and then placing a third shutdown to approximately

service. Additionally, the reactor water level was raised a recirculation pump was

508 cm [200 inches] above the top of active fuel and

started.

conditions

The immediate cause of the event was determined to be plant cooling operating

established by a temporary procedure change to the shutdown

through the reactor

procedure that failed to provide sufficient forced flow procedure change had

core to prevent thermal stratification. The temporary

pumps

been implemented to allow shutdown operations with all recirculationlevel at which

secured and the nominal reactor water level less than the (approximately 470 cm

spillover from the core region to the annulus is assured

been developed

[185 inches] above the top of active fuel). The change had a requirement (stated

from a draft engineering evaluation, but did not includeshutdown cooling flow

in the body of the evaluation) to maintain a specified shutdown cooling

of 22,712 liters per minute [6,000 gpm]. Instead, the usual which, due

flow of about 11,735 liters per minute [3,100 gpm] was maintainedheatup.

to the specified configuration, allowed the inadvertent reactor

and NRC

Further details can be found in Licensee Event Report 50-219/93-002 Augmented Inspection Team Inspection Report No. 50-219/93-80.

Discussion

change

This event at Oyster Creek indicated that the temporary procedure review process did

represented a significant procedure revision and that the

was implemented. The

not identify deficiencies in the procedure before it engineering

temporary procedure change had been developed from a draft in operation would

evaluation which concluded that two shutdown cooling loops

of the

adequately cool the core. An additional assumption in the body at its

evaluation was that each loop of shutdown cooling would be operating

gpm], for a total flow

design flow rate of 11,356 liters per minute [3,000 would be

rate of 22,712 liters per minute [6,000 gpm]. This flow rate

at the

adequate to induce spillover from the core region to the annulus that implemented

reduced nominal water level. The temporary procedure change

flow rate of 22,712 the engineering evaluation did not require a minimum the

operators following

liters per minute [6,000 gpm]. As a result, the loops in

deficient temporary procedure change placed two shutdown cooling

cooling water to the

operation, but did not provide sufficient shutdown addition, the

reactor core to maintain reactor vessel temperatures. In for monitoring

temporary procedure change contained no provision or guidance

heat was being adequately removed

available instruments to ensure that decay

from the reactor core.

the

As part of the licensee corrective actions, the licensee reviewedchanges and

effectiveness of its safety review process concerning temporary

who

provided training on the subject of this event to all site personnel

perform technical and safety reviews.

IN 93-45 June 16, 1993 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 Offic of

Nuclear Reactor Regulation (NRR) project manager.

Brian K. Grimes, Director

Division of Operating Reactor

Support

Office of Nuclear Reactor Regulation

Technical contacts: James S. Stewart, RI

(215) 337-5240

Peter C. Wen, NRR

(301) 504-2832 Attachments:

1. Figure 1, *Oyster Creek Shutdown Cooling System

Flow With Open Recirculation Loop"

2. List of Recently Issued NRC Information Notices

K. / I'l I

Attachment 1

1iK 93-45 June 16, 1993 Steam Flow *-

4- Open Recirculation

TORecirculation Loop

  1. ~Loop

Shutdown Cooling

System

(3 Cooling Loops)

Figure 1 Oyster Creek Shutdown Cooling System Flow With Open Recirculation Loop

I

Attachment 2 IN 93-45 June 16, 1993 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information Date of

Notice No. Subject Issuance Issued to

93-44 Operational Challenges 06/15/93 All holders of OLs or CPs

During A Dual-Unit for nuclear power reactors.

Transient

93-43 Use of Inappropriate 06/10/93 All holders of OLs or CPs

Lubrication Oils in for nuclear power reactors.

Safety-Related Applications

93-42 Failure of Anti-Rotation 06/09/93 All holders of OLs or CPs

Keys in Motor-Operated for nuclear power reactors.

Valves Manufactured by

Velan

93-41 One Hour Fire Endurance 05/28/93 All holders of OLs or CPs

Test Results for Thermal for nuclear power reactors.

Ceramics Kaowool, 3M

Company FS-195 and

3M Company Interam E-50

Barrier Systems

93-40 Fire Endurance Test 05/26/93 All holders of OLs or CPs

Results for Thermal for nuclear power reactors.

Ceramics FP-60 Fire

Barrier Material

,93-39 Radiation Beams from 05/25/93 All holders of OLs or CPs

Power Reactor Biolog- for nuclear power reactors.

ical Shields

93-38 Inadequate Testing of 05/24/93 All holders of OLs or CPs

Engineered Safety for nuclear power reactors.

Features Actuation

System

93-37 Eyebolts with Indeter- 05/19/93 All holders of OLs or CPs

minate Properties In- for nuclear power reactors.

stalled in Limitorque

Valve Operator Housing

Covers

0L - Operating License

CP - Construction Permit

IN 93-45 June 16, 1993 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 !1gnd by

Brian K. Gdmeg

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts: James S. Stewart, RI

(215) 337-5240

Peter C. Wen, NRR

(301) 504-283],

Attachments: 6

1. Figure 1, "Oyster Creek Shutdown Cooling System

Flow With Open Recirculation Loop'

2. List of Recently Issued NRC Information Notices

  • rFF pRmVrnus CONCURRFNCF

OFFICE *OGCB:DORS *DRS:RI **SC:DRS:RI **BC:DRS:RI **D:DRS:RI

NAME PCWen/vsb JSStewart PKEapen JPDurr MWHodges

DATE 04/29/93 05/03/93 03/19/93 03/19/A3 .03/19/93

_______- _ .

  • Tech Ed. I *C:OGCB:DORS-- *D:DSSA:NRR

RSanders IGHMarcus ACThadani

04/29/93 05/10 05/24/93

    • SEE MEMO FROM M.. HODGES TO B.K. GRIMES

=

.

DOCUMENT NAME: 93-45.IN

DATED 3/19/93 PM (A. Dromerick), EAB (J. Carter) and AIT

Team Leader (J. Beall) were consulted during

the development of this IN.

IN 93-XX

May xx, 1993 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.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts: James S. Stewart, Region I

(215) 337-5240

Peter C. Wen, NRR

(301) 504-2832 Attachments:

1. Oyster Creek Shutdown Cooling System Flow With Open Recirculation Loop

2. List of Recently Issued NRC Information Notices

  • SEE PREVIOUS CONCURRENCE

OFFICE *OGCB:DORS *DRS:RI **SC:DRS:RI **BC:DRS:RI **D:DRS:RI

NAME PCWen/vsb JSStewart PKEapen JPDurr MWHodges

DATE l04/29/93 l05/03/93 I 03/19/93 l 03/19/93 l03/19/93

  • Tech Ed. *C:OGCB:DORS D:DORS:NRR

IRSanders GHMarcus BKGrimes

04/29/93 _ 05/10/93 ;05/ /93 4 xk)

onf~~~l oI~tsPIm

- - - - 1F

UULUIMNI NAMI: UIIrMUN .PW) **SEE MEMO FROM M.W. HODGES TO B.K. GRIMES

DATED 3/19/93 PM (A. Dromerick), EAB (J. Carter) and AIT

Team Leader (J. Beall) were consulted during

the development of this IN.

530

AV 'I/tllos

ACiwAt #

fA);mli v-

IN 93-XX

May xx, 1993 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.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts: James S. Stewart, Region I

(215) 337-5240

Peter C. Wen, NRR

(301) 504-2832 Attachments:

1. Oyster Creek Shutdown Cooling System Flow With Open Recirculation Loop

2. List of Recently Issued NRC Information Notices

  • SEE PREVIOUS CONCURRENCE .

OFFICE *OGCB:DORS DRS:RI SC:DRS:RI BC:DRS:RI D:DRS:RI

NAME PCWen/vsb 4SStewart PKEapen JPDurr MWHodges

DATE 04/29/93 05/3,0 Cal P/1/93 0/ l/9 3 I__ 1_/93_J

  • Tech Ed. C:OGCB:DORS D:DORS:NRR 4xx %E memo MYS

Fizz 144 RSanders GHMarcus Ci~l BKGrimes 44 1/1 A/3

04/29/93 05/ 1q993 105/ /93 DOUUMENT NAME: OCTPCIN.PW PA (A 'rolnerlk&) , 1 (. Covte). t

AlT Team Leader (J. &3eA.A) LxQe cuAJX4A

Alxrzrl t. 4JeLt"e'4 . tk& z4BJ

IN 93-XX

May xx, 1993 Page 2 of

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.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts: James S. Stewart, Region I

(215) 337-5240

Peter C. Wen, NRR

(301) 504-2832 Attachments:

1. Oyster Creek Shutdown Cooling System Flow With Open Recirculation Loop

2. List of Recently Issued NRC Information Notices

OFFICE OBORS DRS:RI SC:DRS:RI BC:DRS:RI D:DRS:RI

NAME PCWen/vsb JSStewart PKEapen JPDurr MWHodges

DATE _/aq/93_ 05/ /93 05/ /93 05/ /93 105/ /93 Tech Ed. C:OGCB:DORS D: DORS:NRRI

flU"AJA& GHMarcus BKGrimes

ON/.11/93 05/ /93 05/ /93

%^rrlT scur -rnT -ab

UUUMt Ii NAMt: ULIrMLIN.fW


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