Information Notice 1992-47, Intentional Bypassing of Automatic Actuation of Plant Protective Features

Intentional Bypassing of Automatic Actuation of Plant Protective Features
	ML031210746
Person / Time
Issue date:	06/29/1992
From:	Rossi C; Office of Nuclear Reactor Regulation
To:	;
References
	IN-92-047, NUDOCS 9206230193
	Download: ML031210746 (10)
	v • d • e

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 June 29, 1992 NRC INFORMATION NOTICE 92-47:

INTENT

IONAL BYPASSING OF AUTOMATIC

ACTUATION OF PLANT PROTECTIVE FEATURES

Addressees

power

All holders of operating licenses or construction permits for nuclear

reactors.

Purpose

information

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

notice to alert licensees to the importance of having formal

features. It is

training regarding limitations on bypassing plant protective to

expected that recipients will review the information for applicability

to avoid similar

their facilities and consider actions, as appropriate, notice are not

problems. However, suggestions contained in this information is

NRC requirements; therefore, no specific action or written response

required.

Description of Circumstances

River Nuclear

On December 8, 1991, the Florida Power Corporation's Crystal system (RCS)

Station, Unit 3, experienced a slow loss of reactor coolant

spray valve

pressure at 10 percent power during startup, because a pressurizer determine

did not promptly

failed in a partially open position. The operators misled by an

the cause of the pressure decrease, in part, because they were

Believing the pressure

erroneous spray valve closed position indication. subsequently

decrease to result from an increasing steam demand, the operators RCS temperature

withdrew control rods several times in an attempt to maintain

as steam flow was increased in preparation for loading the generator.

tripped on

However, the RCS pressure continued to decrease, and the reactor B Not Bypassed"

low pressure. Approximately 2 minutes later, the "ES A and

that the high pressure injection

alarms annunciated. These alarms indicate are not blocked, (HPI) system and other engineered safeguards (ES) functions

plant cooldown. Approximately 1 although they may be blocked during normal the ES bypass

minute later, a control room operator inappropriately actuated

later, when a

switches for the A and B HPI system. Approximately 6 minutes the system

sufficient number of actuation logic bistables tripped to actuate

Operations Superintendent questioned

if it had not been bypassed, the Acting and the ES

of bypassing the ES,

the Shift Supervisor about the advisability and other

was then unbypassed at which time the high pressure injection

of the high

systems activated. Operators then established manual control

9206230193 z2r

IN 92-47 June 29, 1992 pressure injection system to maintain RCS pressure above 1500 psig.

operators did not determine the cause of the decrease in RCS pressure The

after the spray line isolation valve was closed about an hour later. until

Discussion

One of the significant lessons of the Three Mile Island, Unit 2, (TMI-2)

accident was that the core damage resulted from operators manually terminating

safety injection based on an inaccurate diagnosis of plant conditions.

1979, the NRC issued a series of Bulletins requesting licensees to reviewIn

operating procedures and training to ensure that operators do not override

automatic ESF actuation without carefully reviewing plant conditions.

the accident at TMI-2, licensees made many enhancements to emergency After

procedures to improve the operator's control of safety functions and operating

engineered safety features.

At Crystal River, the licensee's staff lacked formal guidance delineating

limitations on bypassing the automatic actuation of engineered safeguards

functions. This lack of guidance may have contributed to having high

pressure

injection bypassed with the plant in a degraded condition for approximately

6 minutes without understanding the cause of the decrease in RCS pressure.

One of the licensee's corrective actions was to develop administrative

guidance on when it is appropriate to bypass the automatic actuation

engineered safeguards functions. This guidance has been incorporatedof

plant procedures.- into

-_

This information notice requires no specific action or written response.

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

the technical contact listed below or the appropriate Office of Nuclearcontact

Reactor Regulation (NRR) project manager.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical contact: Thomas Koshy, NRR

(301) 504-1176 Attachment: List of Recently Issued NRC Information Notices

Attachment

IN 92-47 June 29, 1992 Page 1 of I

LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information Date of

Notice No. Subject Issuance Issued to

92-46 Thermo-Lag Fire Barrier 06/23/92 All holders of OLs or CPs

Material Special Review for nuclear power reactors.

Team Final Report Findings, Current Fire Endurance

Tests, and Ampacity Cal- culation Errors

92-45 Incorrect Relay Used in 06/22/92 All holders of OLs or CPs

Emergency Diesel Generator for nuclear power reactors.

Output Breaker Control

Circuitry

92-44 Problems with Westing- 06/18/92 All holders of OLs or CPs

house DS-206 and DSL-206 for nuclear power reactors.

Type Circuit Breakers

92-43 Defective Molded Phen- 06/09/92 All holders of OLs or CPs

olic Armature Carriers for nuclear power reactors.

Found on Elmwood Con- tactors

92-42 Fraudulent Bolts in 06/01/92 All holders of OLs or CPs

Seismically Designed for nuclear power reactors.

Walls

92-41 Consideration of the 05/29/92 All holders of OLs or CPs

Stem Rejection Load in for nuclear power reactors.

Calculation of Required

Valve Thrust

92-40 Inadequate Testing of 05/27/92 All holders of OLs or CPs

Emergency Bus Under- for nuclear power reactors.

voltage Logic Circuitry

92-39 Unplanned Return to 05/13/92 All holders of OLs or CPs

Criticality during for nuclear power reactors.

Reactor Shutdown

OL = Operating License

CP = Construction Permit

IN 92-47 June 29, 1992 pressure injection system to maintain RCS pressure above 1500 psig. The

operators did not determine the cause of the decrease in RCS pressure until

after the spray line isolation valve was closed about an hour later.

Discussion

One of the significant lessons of the Three Mile Island, Unit 2, (TMI-2)

accident was that the core damage resulted from operators manually terminating

safety injection based on an Inaccurate diagnosis of plant conditions. In

1979, the NRC issued a series of Bulletins requesting licensees to review

operating procedures and training to ensure that operators do not override

automatic ESF actuation without carefully reviewing plant conditions. After

the accident at TMI-2, licensees made many enhancements to emergency operating

procedures to improve the operator's control of safety functions and

engineered safety features.

At Crystal River, the licensee's staff lacked formal guidance delineating

limitations on bypassing the automatic actuation of engineered safeguards

functions. This lack of guidance may have contributed to having high pressure

injection bypassed with the plant in a degraded condition for approximately

6 minutes without understanding the cause of the decrease in RCS pressure.

One of the licensee's corrective actions was to develop administrative

guidance on when it is appropriate to bypass the automatic actuation of

engineered safeguards functions. This guidance has been incorporated into

plant procedures.

This information notice requires no specific action or written response. If

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

the technical contact listed below or the appropriate Office of Nuclear

Reactor Regulation (NRR) project manager. Original Signed by

OZ411 E.RoWd

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical contact: Thomas Koshy, NRR

(301) 504-1176 Attachment: List of Recently Issued NRC Information Notices

The designated personnel in the Human Factors Assessment Branch, Operator

Licensing Branch, and Reactor Systems Branch concurred in the draft attached

to the memorandum from William T. Russell to Edward L. Jordan dated

April 28, 1992.

SEE PREVIOUS CONCURRENCE

OEAB:DOEA:NRR ADM:RPB SC/OEAB:DOEA:NRR C/OEAB:DOEA:NRR

TKoshy* JMaln* DFischer* AChaffee*

05/20/92 05/27/92 05/20/92 05/20/92 RII D/DSP:AEOD C/OGCB:DOEA:NRR D

LReyes* TNovak* CBerlinger* ,CC~oriP*.

05/26/92 05/26/92 05/28/92 '-8 Document Name: 92-47.IN

I I

IN 92-XX

May xx, 1992 then established manual control of the high pressure injection system to

maintain RCS pressure above 1500 psig. The operators did not determine the

cause of the decrease in RCS pressure until after the spray line isolation

valve was closed about an hour later.

Discussion

One of the significant lessons of the Three Mile Island, Unit 2 (TMI-2),

accident was that the core damage resulted from operators manually terminating

safety injection based on an inaccurate diagnosis of plant conditions. In

1979, the NRC issued a series of Bulletins to direct licensees to review

operating procedures and training to ensure that operators do not override

automatic ESF actuation without carefully reviewing plant conditions. After

the accident at TMI-2, the licensees made many enhancements to emergency

operating procedures to improve the operator's control of safety functions and

engineered safety features.

At Crystal River, the licensee's staff lacked formal guidance on conditions

that permit bypassing the automatic actuation of engineered safeguards

functions. This lack of guidance may have contributed to having high pressure

injection bypassed with the plant in a degraded condition for approximately 6 minutes without having specific procedural guidance or appropriate management

involvement. One of the licensee's corrective actions was to develop

administrative guidance on when it is appropriate to bypass the automatic

actuation of engineered safeguards functions. This guidance has been

incorporated into plant procedures.

This information notice requires no specific action or written response. If

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

the technical contact listed below or the appropriate Office of Nuclear

Reactor Regulation (NRR) project manager.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical contact: Thomas Koshy, NRR

(301) 504-1176 Attachment: List of Recently Issued NRC Information Notices

The designated personnel in the Human Factors Assessment Branch, Operator

Licensing Branch, and Reactor Systems Branch concurred in the draft attached

to the memorandum from William T. Russell to Edward L. Jordan dated

April 28, 1992.

SEE PREVIOUS CONCURRENCE

OEAB:DOEA:NRR ADM:RPB SC/OEAB:DOEA:NRR C/OEAB:DOEA:NRR

TKoshy* JMain* DFischer* AChaffee*

05/20/92 05/27/92 05/20 92 05/20/92 RII D/DSP:AEOD C/ECB: A D/DOEA

LReyes* TNovak* CBerlj9nger CRossi

05/26/92 05/26/92 6/ /92 / /92 Document Name: C:\BYPASS1 (ATB)

r I ,

IN 92-XX

May xx, 1992 injection system to maintain RCS pressure above 1500 psig. The cause of the

decrease in RCS pressure remained unknown to the operators until after the

spray line isolation valve was closed about an hour later.

Discussion

One of the significant lessons of the Three Mile Island, Unit 2, accident was

that the core damage was a result of operators manually terminating safety

injection based on an inaccurate diagnosis of existing plant conditions. A

series of NRC Bulletins was issued in 1979, that directed licensees, in

general, to review operating procedures and training to ensure that operators

do not override automatic ESF actuation without careful review of plant

conditions. Many post-TMI enhancements were made to emergency operating

procedures to improve operator control of safety functions and engineered

safety features.

At Crystal River, the licensee's staff lacked formal guidance on conditions

that permit bypassing automatic actuation of engineered safeguards functions.

This lack of guidance may have contributed to having high pressure injection

bypassed with the plant in a degraded condition for approximately six minutes

without having specific procedural guidance or appropriate management

involvement. One of the licensee's corrective actions was to develop

administrative guidance on when it is appropriate to bypass automatic

actuation of engineered safeguards functions. This guidance has been, or will

be, incorporated into plant procedures as appropriate.

This information notice requires no specific action or written response. If

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

the technical contact listed below or the appropriate Office of Nuclear

Reactor Regulation (NRR) project manager.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical contact: Thomas Koshy, NRR

(301) 504-1176 Attachment: List of Recently Issued NRC Information Notices

The designated personnel in the Human Factors Assessment Branch, Operator

Licensing Branch, and Reactor Systems Branch concurred in the draft attached

to the memorandum from William T. Russell to Edward L. Jordan dated

April 28, 1992. t C.t

SEE PREVIOUS CONCURRENCE

OEAB:DOEA:NRR ADM:RPB SC/OEAB:DOEA:NRR C/OEAB:DOEA:NRR RII

TKoshy* JMain q DFischer* AChaffee* LReyes

O , 5/27/92 05/20/92 05/20/92 5/2L/92 D/DSP:AEOD C/OGCB:DG EA:NRR D/DOEA

TNovak CBerlingeer CRossi

5/x6 /92 / /92 / /92 Document Name: C:\BYPASS1 (ATB)

I

- IN 92-XX