Information Notice 1996-65, Undetected Accumulation of Gas in Reactor Coolant System and Inaccurate Reactor Water Level Indication During Shutdown: Difference between revisions
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| issue date = 12/11/1996 | | issue date = 12/11/1996 | ||
| title = Undetected Accumulation of Gas in Reactor Coolant System and Inaccurate Reactor Water Level Indication During Shutdown | | title = Undetected Accumulation of Gas in Reactor Coolant System and Inaccurate Reactor Water Level Indication During Shutdown | ||
| author name = Martin | | author name = Martin T | ||
| author affiliation = NRC/NRR | | author affiliation = NRC/NRR | ||
| addressee name = | | addressee name = | ||
Revision as of 06:39, 14 July 2019
UNITED STATES NUCLEAR REGULATORY
COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555-0001 December 11, 1996 NRC INFORMATION
NOTICE 96-65: UNDETECTED
ACCUMULATION
OF GAS IN REACTOR COOLANT SYSTEM AND INACCURATE
REACTOR WATER LEVEL INDICATION
DURING SHUTDOWN
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 ongoing issues related to an undetected
loss of reactor coolant inventory
at Haddam Neck caused by an accumulation
of nitrogen in the reactor coolant system. 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.Background
Information
Notice (IN) 94-36, "Undetected
Accumulation
of Gas in Reactor Coolant System," issued on May 24, 1994, discussed
an event at the Sequoyah Nuclear Power Plant in September
1993 where gas accumulated
in the reactor coolant system (RCS). The gas accumulated
because the temperature
in the volume control tank was much lower than normally expected.
.(This lower temperature
resulted from unusually
low component
cooling water temperatures
and from a maintenance
problem with a cooling water valve that reduced the heat sink temperature
in the letdown heat exchanger.)
The lower temperatures
increased the solubility
of gas in the volume control tank water so that there was more dissolved
gas in the water. When the water was transferred
to the RCS by the charging system and heated up in the reactor vessel, the gas came out of solution and collected
in the RCS. This information
notice also discussed
a similar issue which occurred at the Salem Nuclear Generating
Station on April 12, 1994.IN 96-37, "Inaccurate
Reactor Water Level Indication
and Inadvertent
Draindown
During Shutdown," issued on June 18, 1996, discussed
an event which occurred on September
13, 1995, at Surry Unit 1. The plant was in cold shutdown and depressurized.
Operators
had closed the reactor head vent to install the reactor vessel cavity seal ring. After the seal ring was in place, the reactor head vent was not reopened.
This resulted in a loss of function of the only reactor vessel water level indication.
As pressurizer
relief tank nitrogen pressure was gradually
being reduced, an operator saw the standpipe
indicated
level increase as the PD~tEpb~c
9^r 9AmO}'1I 4JI;~.OGO;L.x ' -11 L>,Paydojlj
e I W I1I .X- Lor-n
K1-'IN 96-65 December 11, 1996 gas bubble trapped in the reactor vessel head expanded, forcing water out of the reactor and up the surge line and standpipe.
Unaware of the closed head vent and believing
the standpipe
level indication, the operator increased
letdown from the reactor coolant system cold leg piping to maintain indicated
level. This effectively
reduced the inventory
In the RCS by approximately
17.0 cubic meters [4500 gallons] over a period of 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />.Description
of Circumstances
The reactor at Haddam Neck was in cold shutdown and decay heat was being removed by the residual heat removal (RHR) system using the "A' RHR pump. The RCS was depressurized
and a temporary
primary vent header was connected
to the reactor vessel head. The volume control tank was being maintained
at a pressure of 310 kPa [30 psig].rhe RCS loop stop valves had been closed to Isolate the reactor vessel from the steam generators.
The Technical
Specification
required boration flow path was from the boric acid metering tank, through the chemical and volume control system metering pump, and into the RCS. The reactor vessel level indication
system (RVLIS) and core exit thermocouples
were disconnected
in preparation
for removal of the reactor vessel head. The operators
were using pressurizer
level indication
and cavity level indication
to monitor reactor vessel level (see Attachment
1).On August 28, 1996, the metering pump was to be declared inoperable
because of an upcoming surveillance
test on the emergency
power supply for the pump, requiring
the alignment
of a different
boric acid flow path. During the alignment, the operator opened both valve BA-V-354 (blended makeup to the volume control tank) and BA-V-355 (blended makeup to the charging pump suction).
It appears that following
this operation
the operator may have failed to fully seat one isolation
valve (BA-V-355)
between the top of the volume control tank (nitrogen
gas space) and the RCS (see Attachment
2). Note: the procedure
in use during the alignment
did not allow valve BA-V-355 and BA-V-354 to be open at the same time. This allowed nitrogen from the volume control tank to leak from the volume control tank, through several closed, leaking valves in the chemical and volume control system, and into the reactor vessel. The installed
vent system was unable to vent off nitrogen as fast as the nitrogen was being added to the reactor vessel and a nitrogen bubble accumulated
in the vessel head region. As the nitrogen gas displaced
water from the reactor vessel Into the pressurizer, the water level in the reactor vessel decreased
and the water level in the pressurizer
increased.
The pressurizer
level instrumentation
erroneously
indicated
that the reactor vessel was full of water. Pressurizer
level slowly increased
because of the displacement
of water from the reactor vessel by nitrogen gas. The operators
believed that the level increase was caused by water leaking into the RCS through the loop stop valves. The operators
tightened
the valves to stop the leakage. Water continued
to be displaced
from the reactor vessel by the growing nitrogen bubble. However, this was masked by the operators
removing RCS inventory
to remove the reactor vessel conoseals.
For approximately
four days, control room operators were unaware that nitrogen gas was leaking into the reactor vessel and causing the level in the reactor vessel to decrease.
-IN 96-65 December 11, 1996 On September
1, 1996, the nitrogen gas supply to the volume control tank was isolated in an attempt to identify the source of the relatively
high nitrogen usage. The isolation
of the nitrogen gas stopped the nitrogen leakage into the RCS. The vent header system capacity now exceeded the rate of gas intrusion
and the vent began to release the nitrogen which had accumulated
in the reactor vessel. The volume of nitrogen being removed from the reactor vessel was replaced by the water in the pressurizer.
The pressurizer
level rapidly decreased until the level indication
decreased
off scale (low). Six additions
of water to the RCS, totalling
approximately
18.9 cubic meters (5000 gallons), were required to stabilize pressurizer
level within the normal range.Discussion
The event at Haddam Neck revealed a number of weaknesses.
However, there are three issues which the NRC has determined
warrant particular
notice. These issues are: (1) Inaccurate
reactor vessel level instrumentation;
(2) Inadequate
reactor coolant inventory balance; and (3) Non-condensible
gas intrusion
into the RCS. These issues are discussed below. An NRC augmented
inspection
team evaluated
this event and reported its findings in NRC Inspection
Report 50-213196-80.
Inaccurate
Reactor Vessel Level Instrumentation
Lack of accurate reactor vessel level instrumentation
and lack of adequate inventory balances while shutdown are issues of generic concem. The NRC has issued several generic communications
on the issue: these are listed in the "Related Generic Communications" section. These generic communications
discuss numerous events where safety-related
equipment
operability
was challenged
because of inaccurate
level instrumentation.
At Haddam Neck, the absence of direct reactor vessel monitoring
instrumentation
had an adverse affect on the operators'
ability to monitor reactor vessel conditions.
The available level instruments (pressurizer
level and cavity level) did not provide a direct indication
of reactor vessel level, The level instrumentation
measured actual level in the pressurizer
which the operators
believed was representative
of reactor vessel level because the pressurizer
air space was vented to the same vent header as the reactor vessel head (see Attachment
1).During this event, pressurizer
level indication
and cavity level indication -were not representative
of actual reactor vessel level because of a difference
in pressure between the reactor vessel head and the pressurizer
air space. The difference
in pressure was caused by the inability
of the installed
reactor vessel head vent system to remove nitrogen gas as fast as it was being introduced
into the RCS.RVLIS, which does provide a direct reactor vessel level indication, was disconnected
in preparation
for refueling
maintenance
activities.
The core exit thermocouples
are another direct indication
of reactor vessel conditions.
The core exit thermocouples
were also disconnected
during the duration of this event.The RVLIS indicates
reactor vessel level at discrete elevations.
During this event, the RVLIS would have indicated
abnormal reactor vessel level when the actual level dropped below the
K>IN 96-65 December 11, 1996 reactor vessel flange. Following
this event, local RVLIS readings were collected
and a temporary
jumper was purchased
and installed
to provide RVLIS indications
in the control room. A second jumper was installed
to provide core exit thermocouple
indication
in the control room.Inadequate
Reactor Coolant Inventory
Balance The licensee had not maintained
an RCS inventory
balance to account for the transfer of water into and out of the RCS. No detailed procedural
guidance existed which required an inventory
balance for draindown
operations.
The operators
compensated
for a lack of detailed procedural
guidance by writing instructions
in accordance
with administrative
control procedure
1.2-5.3, "Evaluation
of ActivitiesXEvolutions
Not Controlled
by Procedure." The instructions
written in accordance
with administrative
control procedure
1.2-5.3 do not require the same level of review and approval that other plant procedures
receive. The guidance written for the RCS draindown
did not require RCS inventory
balances or specify reference levels.On August 29, 1996, plant management
made the decision to suspend refueling
activities
over the weekend. The operators
were directed to and did refill the RCS. However, where 5000 gallons had been removed from the RCS earlier, only 1000 gallons were added to the RCS to reach essentially
the same indicated
level. (The resulting
8-inch difference
in P2, level indication
between before and after only represented
500 gallons of the inventory difference
not the 4000 gallons which existed.)The magnitude
of the apparent RCS inventory
discrepancy
was not explained
to operations
management
nor did the operators
solicit engineering
and technical
support to assist in resolving
this discrepancy.
The licensee had experienced
leakage of the loop stop valves during past outages, however, an inventory
balance may have alerted the operators
to the actual magnitude
of the inventory
discrepancy, and may have caused the operators
to question their initial conclusion
that the increase in pressurizer
level was caused by leaking stop valves.Non-Condensible
Gas Intrusion
into the RCS Gas intrusion
into the RCS and safety-related
cooling system piping is an issue of generic concem. The NRC has issued several generic communications
on the issue: these are listed in the "Related Generic Communications" section. These generic communications
discuss numerous events where safety-related
equipment
was potentially
rendered inoperable
because of gas intrusion.
The generic communications
discuss the various processes
by which non-condensible
gases have accumulated
unknown to the reactor operators
in the RCS and safety-related
cooling system piping. The event at Haddam Neck illustrates
that gas intrusion
events continue to occur in spite of the operational
experience
available
to the industry.At Haddam Neck, nitrogen intrusion
into the RCS could potentially
result in gas binding and common mode failure of the decay heat removal pumps and the charging pumps. In
IN 96-65 December 11, 1996 addition, nitrogen present in the RCS could potentially
interfere
with the ability of the steam generators
to remove heat from the RCS via natural circulation
cooling. The significance
of the loss of the charging pumps at Haddam Neck is that a method of injecting
water into the reactor vessel would be lost and that the charging pumps are needed to fill the RCS before opening the loop stop valves. The loop stop valves would need to be opened to allow the RCS to communicate
with the steam generators, a condition
necessary
for the steam generators
to remove heat from the RCS via natural circulation.
In addition, the volume of the RCS increases
significantly
with the loop stop valves open, thus providing
a larger passive heat sink which would slow the heating of the RCS.At Haddam Neck the overpressure
in the volume control tank was purposely
maintained
by the licensee as an independent
source of motive force to inject water into the RCS in the event of a loss of other injection
methods. The potential
hazard of this condition
is that nitrogen may Intrude into the RCS if valves relied upon to isolate the volume control tank from the RCS either leak or are not properly controlled.
During the event, the operators
attempted
to start the "B" RHR pump, however, it was found to be seized. The licensee believes that the seizure occurred at the end of the last surveillance
test and was not related to the gas intrusion
event. The operators
were unaware that the "B" RHR had seized following
its last operation
on August 19, 1996. After the event, the licensee determined
that the "B" RHR pump was inoperable
throughout
the event. The failure of the "B" RHR pump added to the significance
of this event. If the "A" pump was damaged, the RHR system would not be available
to remove decay heat. A mitigating
condition
at Haddam Neck is that two trains of the low pressure injection
system were available.
The abnormal operating
procedure
for a loss of RHR requires that a cavitating
RHR pump be secured and vented. However, the location of the RHR pump vents is not optimal and significant
difficulty
was encountered
during venting the "B" RHR pump following
maintenance
to address its seizure. Therefore, an effective
venting of a RHR pump may not have been easy to achieve during an event if a pump had become gas bound.Related Generic Communications
Information
Notice 88-23, "Potential
for Gas Binding of High-Pressure
Safety Injection
Pumps During a Loss-of-Coolant
Accident," May 12, 1988.Information
Notice 88-23, Supplement
1, "Potential
for Gas Binding of High-Pressure
Safety Injection
Pumps During a Loss-of-Coolant
Accident," January 5, 1989.Information
Notice 89-67, "Loss of Residual Heat Removal Caused by Accumulator
Nitrogen Injection," September
13, 1989.Information
Notice 88-23, Supplement
2, "Potential
for Gas Binding of High-Pressure
Safety Injection
Pumps During a Loss-of-Coolant
Accident," January 31, 1990.
K-/IN 96-65 December 11, 1996 Information
Notice 90-64, "Potential
for Common-Mode
Failure of High Pressure Safety Injection
Pumps or Release of Reactor Coolant Outside Containment
During a Loss-of-Coolant Accident," October 4, 1990.Information
Notice 88-23, Supplement
3, "Potential
for Gas Binding of High-Pressure
Safety Injection
Pumps During a Loss-of-Coolant
Accident," December 30, 1990.Information
Notice 88-23, Supplement
4, "Potential
for Gas Binding of High-Pressure
Safety Injection
Pumps During a Loss-of-Coolant
Accident," December 18, 1992.Information
Notice 90-55, Recent Operating
Experience
on Loss of Reactor Coolant Inventory While in a Shutdown Condition," August 31, 1990.Information
Notice 93-93, "Inadequate
Control of Reactor Coolant System Conditions
During Shutdown," December 8, 1993.Information
Notice 94-36, "Undetected
Accumulation
of Gas in Reactor Coolant System," May 24, 1994.Information
Notice 95-03, "Loss of Reactor Coolant Inventory
and Potential
Loss of Emergency
Mitigation
Functions
While in a Shutdown Condition," January 18, 1995.Information
Notice 96-37, "Inaccurate
Reactor Water Level Indication
and Inadvertent
Draindown
During Shutdown," June 18, 1996.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.Thomas T. Martin, Director Division of Reactor Program Management
Office of Nuclear Reactor Regulation
Technical
contacts:
Eric J. Benner, NRR Warren C. Lyon, NRR (301) 415-1171 (301) 415-2947 E-mail: ejb@nrc.gov
E-mail: wcl@nrc.gov
Attachments:
1. The Undetected
Nitrogen Gas Introduction
into the Reactor Vessel from the Charging Line 2. Chemical and Volume Control System 3. List of Recently Issued NRC Information
Notices (1 l 4 [le} u
IN 96-65 KY t) December 11, 1996 Information
Notice 90-64, "Potential
for Common-Mode
Failure of High Pressure Safety Injection
Pumps or Release of Reactor Coolant Outside Containment
During a Loss-of-Coolant Accident," October 4, 1990.Information
Notice 88-23, Supplement
3, "Potential
for Gas Binding of High-Pressure
Safety Injection
Pumps During a Loss-of-Coolant
Accident," December 30, 1990.Information
Notice 88-23, Supplement
4, "Potential
for Gas Binding of High-Pressure
Safety Injection
Pumps During a Loss-of-Coolant
Accident," December 18, 1992.Information
Notice 90-55, Recent Operating
Experience
on Loss of Reactor Coolant Inventory While in a Shutdown Condition," August 31, 1990.Information
Notice 93-93, "Inadequate
Control of Reactor Coolant System Conditions
During Shutdown," December 8, 1993.Information
Notice 94-36, "Undetected
Accumulation
of Gas in Reactor Coolant System," May 24, 1994.Information
Notice 95-03, "Loss of Reactor Coolant Inventory
and Potential
Loss of Emergency
Mitigation
Functions
While in a Shutdown Condition," January 18, 1995.Information
Notice 96-37, "Inaccurate
Reactor Water Level Indication
and Inadvertent
Draindown
During Shutdown," June 18, 1996.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 D. B. Matthews ,4Yomas T. Martin, Director 7 ~Division
of Reactor Program Management
I Office of Nuclear Reactor Regulation
Technical
contacts:
Eric J. Benner, NRR Warren C. Lyon, NRR (301) 415-1171 (301) 415-2947 E-mail: ejbenrc.gov
E-mail: wcl@nrc.gov
Tech Editor has reviewed and concurred
on 10/22/96 Attachments:
1. The Undetected
Nitrogen Gas Introduction
into the Reactor Vessel from the Charging Line 2. Chemical and Volume Control System 3. List of Recently Issued NRC Information
Notices DOCUMENT NAME: G:%EJBlHAD
GAS.IN *SEE PREVIOUS CONCURRENC
l OFC Contacts (A)BC/SRXB:
BC/PECB:DRPM
D/D NAME EBenner* TCollins*
AChaffee*
TMa\/n l_ _ WLyon*DATE 10/30/96 11/05/96 11/25/96 E ,1,96 10/30/96 OFFICIAL RECO)RD COPY
IN 96-XX.) November X, 1996 Information
Notice 90-64, "Potential
for Common-Mode
Failure of High Pressure Safety Injection
Pumps or Release of Reactor Coolant Outside Containment
During a Loss-of-Coolant Accident," October 4, 1990.Information
Notice 88-23, Supplement
3, "Potential
for Gas Binding of High-Pressure
fety Injection
Pumps During a Loss-of-Coolant
Accident," December 30, 1990.Information
Notice 88-23, Supplement
4, "Potential
for Gas Binding of High-P rsure Safety Injection
Pumps During a Loss-of-Coolant
Accident," December 18, 1992.Information
Notice 90-55, Recent Operating
Experience
on Loss of Rea or Coolant Inventory While in a Shutdown Condition," August 31, 1990.Information
Notice 93-93, "Inadequate
Control of Reactor Coolan ystem Conditions
During Shutdown," December 8, 1993.Information
Notice 94-36, "Undetected
Accumulation
of Gabin Reactor Coolant System," May 24, 1994.Information
Notice 95-03, "Loss of Reactor Coolant I entory and Potential
Loss of Emergency
Mitigation
Functions
While in a Shutdo n Condition," January 18, 1995.Information
Notice 96-37, "Inaccurate
Reacto ater Level Indication
and Inadvertent
Draindown
During Shutdown," June 18, 19 This information
notice requires no spe ic action or written response.
If you have any questions
about the information
in this otice, please contact one of the technical
contacts listed below or the appropriate
Offi of Nuclear Reactor Regulation (NRR) project manager.Thomas T. Martin, Director Division of Reactor Program Management
Office of Nuclear Reactor Regulation
Technical
contacts:
Eric .Benner, NRR Warren C. Lyon, NRR (30 415-1171 (301) 415-2947 E- ail: ejbenrc.gov
E-mail: wclInrc.gov
Attachments:
1. The Undetecte
Nitrogen Gas Introduction
into the Rea or Vessel from the Charging Line 2. Chemical a Volume Control System 3. List of Recently Issued NRC Information
Notices DOCUMENT NAME: G:XEJB1%HADGAS.lN
- SEE PREVIOUS CONCURRENCE
OFC Contacts (A)BC/SRXB:
BC/PECB:DRPM
D/D NAME EBenner* TCollins*
AChaffee*
TMaW \WLyon*_DATE 10/30/96 11/05/96 11/25/96 11f96 10/30/96 OFFICIAL RECORD COPY
IN c -KX No~ber X, 1996 Information
Notice 90-64, "Potential
for Common-Mode
Failure of High Pressure ty Injection
Pumps or Release of Reactor Coolant Outside Containment
During a ss-of-Coolant Accident," October 4, 1990.Information
Notice 88-23, Supplement
3, "Potential
for Gas Binding of gh-Pressure
Safety Injection
Pumps During a Loss-of-Coolant
Accident," December 30, 90.Information
Notice 88-23, Supplement
4, "Potential
for Gas Bing of High-Pressure
Safety Injection
Pumps During a Loss-of-Coolant
Accident," Decem r 18,1992.Information
Notice 90-55, Recent Operating
Expenien n Loss of Reactor Coolant Inventory While in a Shutdown Condition," August 31, 1990.Information
Notice 93-93, "Inadequate
Control o eactor Coolant System Conditions
During Shutdown," December 8, 1993.Information
Notice 94-36, "Undetected
A umulation
of Gas in Reactor Coolant System," May 24, 1994.Information
Notice 95-03, "Loss of eactor Coolant Inventory
and Potential
Loss of Emergency
Mitigation
Functions
ile in a Shutdown Condition," January 18, 1995.Information
Notice 96-37, "I ccurate Reactor Water Level Indication
and Inadvertent
Draindown
During Shutdo n," June 18, 1996.This information
notirequires
no specific action or written response.
If you have any questions
about the formation
in this notice, please contact one of the technical
contacts listed below or the ppropriate
Office of Nuclear Reactor Regulation (NRR) project manager.Thomas T. Martin, Director Division of Reactor Program Management
Office of Nuclear Reactor Regulation
Techni contacts:
Eric J. Benner, NRR Warren C. Lyon, NRR (301) 415-1171 (301) 415-2947 E-mail: ejb@nrc.gov
E-mail: wcl@nrc.gov
Aft chments: 1. The Undetected
Nitrogen Gas Introduction
into the Reactor Vessel from the Charging Line 2. Chemical and Volume Control System 3. List of Recently Issued NRC Information
Notices DOCUMENT NAME: G:\EJBlHAD
GAS.IN *SEE PREVIOUS CONCURRENCE
OFC Contacts (A)BC/SRXB:
BCIPECB:DRPM
DIDRPM NAM EBenner* TCollins*
AChaffee A TMartin E WLyon* ___ _DATE 10/30/96 1 5p 11/05/96 ii 66i6 /96 10/30/96 OFFICIAL RECORD COPY
IN 96-XX November X. 1996 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.Thomas T. Martin, Direct Division of Reactor Pr ram Management
Office of Nuclear Re tor Regulation
Technical
contacts:
Eric J. Benner. NRR (301) 415-1171 E-mail: ejb@nrc.gov
Warren C. Lyon. NRR (301) 415-2947 E-mail: wcl@nrc.gov
Attachments:
1. The Undetected
Nitrogen Gas Introdution
into the Reactor Vessel from the Charging Line 2. Chemical and Volume Control Syst 3. List of Recently Issued NRC Inf rmation Notices N NA)M P -XCC \ -XX, r DOCUMENT NAME:ARA.
- SEE PREVIOUS CONCURRCE OFC Co qacts (A)BC/SRXB:
BC/PECB:DRPM
D/DRPM NAME enner* TCollins*
AChaffee TMartin Lyon*DATE 10/30/96 11/05/96 / /96 / /96 10/30/96 OFFICIAL RE CORD COPY
I ' XI<K IN 96-61 November 7. 1996 Information
Notice 90-55, Recent Operating
Experience
on Loss of Reactor Coolant Inventory
While in a Shutdown Condition," August 31, 1990.Information
Notice 93-93, "Inadequate
Control of Reactor Coolant System Conditions
During Shutdown." December 8, 1993.Information
Notice 94-36. "Undetected
Accumulation
of Gas in Reactor Coolant System." May 24, 1994.Information
Notice 95-03. "Loss of Reactor Coolant Inventory
and Potential Loss of Emergency
Mitigation
Functions
While in a Shutdown Condition." January 18. 1995.Information
Notice 96-37. "Inaccurate
Reactor Water Level Indication
and Inadvertent
Draindown
During Shutdown." June 18. 1996.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.Thomas T. Martin, Director Division of Reactor Program Management
Office of Nuclear Reactor Regulation
Technical
contacts: Eric J. Benner, NRR (301) 415-1171 E-mail: ejb@nrc.gov
Warren C. Lyon, NRR (301) 415-2947 E-mail: wcl@nrc.gov
Attachments:
1. Figure 1: Chemical and Volume Control System 2. List of Recently Issued NRC Information
Notices DOCUMENT NAME: G:\EJB1\HAD
GAS.IN *SEE PREVIOUS CONCURRENCE
OFC Contacts (A)BC/SRXB:
BC/PECB:DRPM
D/DRPM NAME EBenner* TCollins*
AChaffee >- TMartin WLyon*_ _ _DATE 10/30/96 11/05/96 It / 1/96 / /96 10/30/96 OFFICIAL RECORD COPY
-IN 96-61 November 7. 1996 Information
Notice 90-55, Recent Operating
Experience
on Coolant Inventory
While in a Shutdown Condition," August Loss of Reactor 31. 1990.Information
Notice 93-93, "Inadequate
Control of Reactor Coolant System Conditions
During Shutdown," December 8. 1993.Information
Notice 94-36. "Undetected
Accumulation
of Gas in Reactor Coolant System," May 24. 1994.Information
Notice 95-03, "Loss of Reactor Coolant Inventory
and Potential Loss of Emergency
Mitigation
Functions
While in a Shutdown Condition," January 18. 1995.Information
Notice 96-37, "Inaccurate
Reactor Water Level Indication
and Inadvertent
Draindown
During Shutdown." June 18. 1996.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.Thomas T. Martin, Director Division of Reactor Program Management
Office of Nuclear Reactor Regulation
Technical
contacts: Eric J. Benner, NRR (301) 415-1171 E-mail: ejb@nrc.gov
Warren C. Lyon. NRR (301) 415-2947 E-mail: wcl@nrc.gov
Attachments:
1. Figure 1: Chemical and 2. List of Recently Issued Volume Control System NRC Information
Notices DOCUMENT NAME: G:\EJB1\HAD
GAS.IN *SEE PREVIOUS CONCURRENCE
OFC Contacts (A)BC/SRXB:
BC/PECB:DRPM
D/DRPM NAME EBenner* TCollins*
AChaffee TMartin WLyon* V-, DATE 10/30/96 11/05/96 Il/(a/96 / /96 10/30/96 l OFFICIAL RECORD COPY
INVi-xx November XX, 1996 Information
Notice 90-55, Recent Operating
Experience
on Coolant Inventory
While in a Shutdown Condition," August Information
Notice 93-93, "Inadequate
Control of Reactor Conditions
During Shutdown," December 8, 1993.Loss of Reactor 31, 1990.Coolant System Information
Notice 94-36, "Undetected
Accumulation
of Gas in Reactor Coolant System," May 24, 1994.Information
Notice 95-03, "Loss of Reactor Coolant Inventory
and Potential Loss of Emergency
Mitigation
Functions
While in a Shutdown Condition," January 18, 1995.Information
Notice 96-37, "Inaccurate
Reactor Water Level Indication
and Inadvertent
Draindown
During Shutdown," June 18, 1996.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.Thomas T. Martin, Director Division of Reactor Program Management
Office of Nuclear Reactor Regulation
Technical
contact(s):
Eric J. Benner, NRR (301) 415-1171 E-mail: ejb@nrc.gov
Warren C. Lyon, NRR (301) 415-2947 E-mail: wcl@nrc.gov
Attachments:
1. Figure 1: Chemical and Volume Control System 2. List of Recently Issued NRC Information
Notices DOCUMENT NAME: G:\EJB1\HADGAS.IN
- SEE PREVIOUS CONCURRENCE
OFC Contacts (A)BC/SRXB:
BC/PECB:DRPM
D/DRPM NAME EBenner* TCollins*
AChaffee TMartin WLyon*DATE 10/30/96 11/05/96 / /96 / /96 10/30/96 OFFICIAL RECORD COPY
IN 94-36, Supp. 1 November XX, 1996 Information
Notice 88-23, Supplement
1. "Potential
for Gas Binding of High-Pressure Safety Injection
Pumps During a Loss-of-Coolant
Accident," January 5. 1989.Information
Notice 89-67. "Loss of Nitrogen Injection." September
13, Information
Notice 88-23, Supplemer Pressure Safety Injection
Pumps Dut January 31, 1990.Residual Heat Removal Caused by Accumulator
1989.it 2, "Potential
for Gas Binding of High-,ing a Loss-of-Coolant
Accident," Information
Notice 90-64, "Potential
for Common-Mode
Failure of High Pressure Safety Injection
Pumps or Release of Reactor Coolant Outside Containment
During a Loss-of-Coolant
Accident," October 4, 1990.Information
Notice 88-23.Pressure Safety Injection December 30. 1990.Information
Notice 88-23.Pressure Safety Injection December 18, 1992.Supplement
3. "Potential
for Gas Binding of High-Pumps During a Loss-of-Coolant
Accident," Supplement
4. "Potential
for Gas Binding of High-Pumps During a Loss-of-Coolant
Accident," Information
Notice 93-93, "Inadequate
Control of Reactor Coolant System Conditions
During Shutdown," December 8. 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.Thomas T. Martin, Director Division of Reactor Program Management
Office of Nuclear Reactor Regulation
Technical
contact(s):
Eric J. Benner, NRR (301) 415-1171 E-mail: ejb@nrc.gov
Warren C. Lyon, NRR (301) 415-2947 E-mail: wcl@nrc.gov
Attachments:
1. Figure 1: Chemical and Volume Control System 2. List of Recently Issued NRC Information
Notices DUCUMLNI NAML: b:\LJBi\MAV
UAb.1N -Ztt FKtVIUUZ LUiNUKKMUL
OFC Contacts (A)BC/SRXB:
BC/PECB:DRPM
D/DRPM NAME EBenner* TCollins*
AChaffee TMartin WLyon*DATE 10/30/96 11/05/96 / /96 , / /96 110/30/96 a-[OFFICIAL
RECORD COPY
IN 94-36. Supp. 1 November XX, 1996 Information
Notice 89-67, "Loss of Residual Heat Removal Caused Nitrogen Injection," issued September
13. 1989.Information
Notice 88-23, Supplement
2, "Potential
for Gas Pressure Safety Injection
Pumps During a Loss-of-Coolant
January 31, 1990.i dei by Accumulator
'7 ing of High-it," issued Information
Notice 90-64. "Potential
for Common-Mod
Tailure of High Pressu Safety Injection
Pumps or Release of Reactor Coolayt Outside Containment
During a Loss-of-Coolant
Accident." issued Octob 4. 1990.Information
Notice 88-23. Supplement
3. "Pote ial for Gas Binding of High-Pressure Safety Injection
Pumps During a Lo -of-Coolant
Accident," issued re December 30. 1990.Information
Notice 88-23, Pressure Safety Injection December 18, 1992.Supplement
Pumps Durii/"Potential
for Gas Binding of High-a Loss-of-Coolant
Accident," issued Information
Notice 93-93. "Inade 4ate Control of Reactor Coolant System Conditions
During Shutdown," i ued December 8. 1993.This information
notice req res no specific action or written response.
If you have any questions
abo the information
in this notice, please contact one of the technical
con cts listed below or the appropriate
Office of Nuclear Reactor Regulaton (NRR) project manager.Thomas T. Martin, Director Division of Reactor Program Management
Office of Nuclear Reactor Regulation
Technical): Eric J. Benner, NRR (301) 415-1171 Internet:
ejbl@nrc.gov
Warren C. Lyon, NRR (301) 415-2947 Internet:
wcl@nrc.gov
Tech ditor At chment: reviewed and concurred
on October 18, 1996.List of Recently Issued NRC Information
Notices Contacts BC/SRXB:DSSA
T0 BC/PECB:DRPM
D/DRPM NAME EBennerrtr6
4X AChaffee TMartin WLyon /0/lX, 'z: zgt,_4ll DATE On) I 6"I /'I/ /96 / /96____ 1 7 t /l%9 / f9[OFIIA ECOR COY]DOCUMENT NAME: G:\EJB1\HAD
GAS.IN
THE UNDETECTED
NITROGEN GAS INTRODUCTION
INTO THE REACTOR VESSEL FROM THE CHARGING LINE Steam Vent Header generator Pressuriier
Pressurizer
(Vent Temporary Hose ri r- ~691' EL Ha Pressurizer
Vent Air (gg Level-Head Full 355" EL-12%Water .301- EL 351 EL Top of He(d.!: Cavty /_ 1° _\\Reactor
Vaevve ,: 2330 EL Indicatore
.Ntogn. 1 9Fae 270" EL>(^i\ HotLeg Gas aDbl o; l lrre LOOb1°P Wate Lin Reacor Cold LegCl 10" Pressurizer
10" RHR Coolant Surge (Lin Suction Line I Pup(Loop 4) (Loop 1) a CY%Loop #4 EL1R9(- I El. 185" -j 27112" EL 172" -/Reactor Hoke lo 1j aU t a inftO Reactor l i n t O f t D l ? * -
CHEMICAL & VOLUME CONTROL SYSTEM NITROGEN GAS LEAK PATH FROM VOLUME CONTROL TANK TO THE RCS To RCS Loop #2 Cold Leg Volume Control Tank (Valve Closed -Leaking By Borde Acid Blender c Oi CD =COC)(D CD O C 3 cn c-or I1: CD CM =o i en C_& --r to Dn
KJ Attachment
3 IN 96-65 December 11, 1996 LIST OF RECENTLY ISSUED NRC INFORMATION
NOTICES Information
Date of Notice No. Subject Issuance Issued to 96-64 96-63 96-62 96-61 96-60 96-59 Modifications
to Con-tainment Blowout Panels Without Appropriate
Design Controls Potential
Safety Issue Regarding
the Shipment of Fissile Material Potential
Failure of the Instantaneous
Trip Function of General Electric RMS-9 Programmers
Failure of a Main Steam Safety Valve to Reseat Caused by an Improperly
Installed
Release Nut Potential
Common-Mode
Post-Accident Failure of Residual Heat Removal Heat Exchangers
Potential
Degradation
of Post Loss-of-Coolant
Recirculation
Capability
as a Result of Debris RCP Seal Replacement
with Pump on Backseat 12/10/96 12/05/96 11/20/96 11/20/96 11/14/96 10/30/96 10/30/96 All holders of OLs or CPs for nuclear reactors All U.S. Nuclear Regulatory
Commission
licensees
authorized
to possess special nuclear material in unsealed quantities
greater than a critical mass All holders of OLs and CPs for nuclear power plants 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 All holders of OLs or CPs for pressurized-water
reactors 96-58 OL = Operating
License CP = Construction
Permit