View source for Information Notice 1996-65, Undetected Accumulation of Gas in Reactor Coolant System and Inaccurate Reactor Water Level Indication During Shutdown

{{Adams
| number = ML031050500
| issue date = 12/11/1996
| title = Undetected Accumulation of Gas in Reactor Coolant System and Inaccurate Reactor Water Level Indication During Shutdown
| author name = Martin T
| author affiliation = NRC/NRR
| addressee name = 
| addressee affiliation = 
| docket = 05000003, 05000010, 05000029, 05000133, 05000155, 05000171, 05000206, 05000213, 05000219, 05000220, 05000237, 05000244, 05000245, 05000247, 05000249, 05000250, 05000251, 05000254, 05000255, 05000259, 05000260, 05000261, 05000263, 05000265, 05000266, 05000267, 05000269, 05000270, 05000271, 05000272, 05000275, 05000277, 05000278, 05000280, 05000281, 05000282, 05000285, 05000286, 05000287, 05000289, 05000293, 05000295, 05000296, 05000298, 05000301, 05000302, 05000304, 05000305, 05000306, 05000309, 05000311, 05000312, 05000313, 05000315, 05000316, 05000317, 05000318, 05000320, 05000321, 05000322, 05000323, 05000324, 05000325, 05000327, 05000328, 05000329, 05000330, 05000331, 05000333, 05000334, 05000335, 05000336, 05000338, 05000339, 05000341, 05000344, 05000346, 05000348, 05000352, 05000353, 05000354, 05000361, 05000362, 05000364, 05000366, 05000368, 05000369, 05000370, 05000373, 05000374, 05000382, 05000387, 05000388, 05000389, 05000390, 05000391, 05000395, 05000397, 05000400, 05000409, 05000410, 05000412, 05000413, 05000414, 05000416, 05000423, 05000424, 05000425, 05000437, 05000438, 05000439, 05000440, 05000441, 05000443, 05000444, 05000445, 05000446, 05000454, 05000455, 05000456, 05000457, 05000458, 05000461, 05000482, 05000483, 05000498, 05000499, 05000508, 05000528, 05000529, 05000530
| license number = 
| contact person = 
| document report number = IN-96-065, NUDOCS 9612060224
| document type = NRC Information Notice
| page count = 18
}}
{{#Wiki_filter: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 hours.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&deg; _\\Reactor

Vaevve ,: 2330 EL Indicatore

.Ntogn. 1 9Fae 270" EL>(^i\ HotLeg Gas aDbl o; l lrre LOOb1&deg;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}}

{{Information notice-Nav}}