Information Notice 1985-85, Systems Interaction Event Resulting in Reactor System Safety Relief Valve Opening Following a Fire-Protection Deluge System Malfunction: Difference between revisions

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{{#Wiki_filter:SSINS No.: 6835 IN 85-85 UNITED STATES
{{#Wiki_filter:SSINS No.:  
6835 IN 85-85


===UNITED STATES===
NUCLEAR REGULATORY COMMISSION
NUCLEAR REGULATORY COMMISSION


OFFICE OF INSPECTION AND ENFORCEMENT
===OFFICE OF INSPECTION AND ENFORCEMENT===
WASHINGTON, D.C.


WASHINGTON, D.C. 20555 October 31, 1985 IE INFORMATION NOTICE 85-85:  SYSTEMS INTERACTION EVENT RESULTING IN REACTOR
20555


===October 31, 1985===
IE INFORMATION NOTICE 85-85:
===SYSTEMS INTERACTION EVENT RESULTING IN REACTOR===
SYSTEM SAFETY RELIEF VALVE OPENING FOLLOWING
SYSTEM SAFETY RELIEF VALVE OPENING FOLLOWING


Line 38: Line 45:
event involving the fire-protection deluge system located in the control room
event involving the fire-protection deluge system located in the control room


ventilation charcoal filter housing. Following inadvertent actuation of this
ventilation charcoal filter housing.


===Following inadvertent actuation of this===
system, an analog transient trip system (ATTS) panel was sprayed with water
system, an analog transient trip system (ATTS) panel was sprayed with water


Line 48: Line 56:
their facilities and consider actions, if appropriate, to preclude a similar
their facilities and consider actions, if appropriate, to preclude a similar


problem occurring at their facilities. However, suggestions contained in this
problem occurring at their facilities.


===However, suggestions contained in this===
notice do not constitute requirements; therefore, no specific action or written
notice do not constitute requirements; therefore, no specific action or written


Line 60: Line 69:
scrammed the reactor from 75% power because of a stuck open low-low-set safety
scrammed the reactor from 75% power because of a stuck open low-low-set safety


relief valve (LLS-SRV). Shorting of one of the two redundant power supplies
relief valve (LLS-SRV).


===Shorting of one of the two redundant power supplies===
and/or possibly intermittent shorting of logic system contacts in the ATTS
and/or possibly intermittent shorting of logic system contacts in the ATTS


panel is believed to have caused the stuck open LLS-SRV. The panel is one of
panel is believed to have caused the stuck open LLS-SRV. The panel is one of


two redundant panels located in the control room. The cause of the electrical
two redundant panels located in the control room.


===The cause of the electrical===
shorts in the affected panel was water intrusion into the panel.
shorts in the affected panel was water intrusion into the panel.


The event began about 8:35 p.m. when an instrument water supply vent valve was
The event began about 8:35 p.m. when an instrument water supply vent valve was


damaged, apparently by dragging of a crane hook along the line. The instru- ment water supply line eventually depressurized causing a portion of the fire- protection deluge system to actuate. The water supply line is located above
damaged, apparently by dragging of a crane hook along the line.
 
The instru- ment water supply line eventually depressurized causing a portion of the fire- protection deluge system to actuate. The water supply line is located above


the control building and the deluge system is located in the control room
the control building and the deluge system is located in the control room
Line 80: Line 93:
Following actuation of the deluge system, approximately 15 to 25 gal of water
Following actuation of the deluge system, approximately 15 to 25 gal of water


backed up into the ventilation header before the system could be secured. The
backed up into the ventilation header before the system could be secured.
 
The


8510290039
8510290039


IN 85-85 October 31, 1985 backup was caused by plugged drains in the charcoal filter housing. Water
IN 85-85 October 31, 1985 backup was caused by plugged drains in the charcoal filter housing.
 
Water


eventually leaked through a hole in the ventilation piping that was located
eventually leaked through a hole in the ventilation piping that was located
Line 90: Line 107:
above the ATTS panel in the control room. Whenthe water sprayed onto the panel, one of two redundant panel power supplies apparently shorted because of water
above the ATTS panel in the control room. Whenthe water sprayed onto the panel, one of two redundant panel power supplies apparently shorted because of water


intrusion into the panel. As a result, a LLS-SRV valve began to cycle open and
intrusion into the panel.


closed. The SRV cycled three times and then opened and remained open. The
As a result, a LLS-SRV valve began to cycle open and
 
closed.
 
The SRV cycled three t imes and then opened and remained open.
 
The


operator manually scrammed the reactor from 75% power. A false turbine high
operator manually scrammed the reactor from 75% power. A false turbine high
Line 98: Line 121:
exhaust pressure trip signal also was generated, temporarily disabling the high
exhaust pressure trip signal also was generated, temporarily disabling the high


pressure core injection (HPCI) system. The reactor core isolation cooling
pressure core injection (HPCI) system.


(RCIC) system was inoperable at the time, so neither HPCI nor RCIC was imme- diately available for use. Fortunately, neither system was needed during the
===The reactor core isolation cooling===
(RCIC) system was inoperable at the time, so neither HPCI nor RCIC was imme- diately available for use.


event. This is because the water level was restored and maintained by the
===Fortunately, neither system was needed during the===
event.


reactor feedwater system until the MSIVs were shut. Subsequent to MSIV closure, water level was maintained by the control rod drive (CRD) system with the
This is because the water level was restored and maintained by the
 
reactor feedwater system until the MSIVs were shut.
 
Subsequent to MSIV closure, water level was maintained by the control rod drive (CRD) system with the


excess water being dumped to the condenser via the reactor-water cleanup-system.
excess water being dumped to the condenser via the reactor-water cleanup-system.
Line 113: Line 142:
The event is of considerable concern because of the potential for multiple
The event is of considerable concern because of the potential for multiple


safety system failures through unanalyzed systems interactions. In this event, the water from the fire-suppression deluge system in the control room caused
safety system failures through unanalyzed systems interactions.
 
In this event, the water from the fire-suppression deluge system in the control room caused
 
opening of a safety relief valve and loss of primary system inventory.


opening of a safety relief valve and loss of primary system inventory. The
The


event could have been seriously aggravated by the spurious HPCI turbine high
event could have been seriously aggravated by the spurious HPCI turbine high
Line 121: Line 154:
exhaust pressure-trip-that-wasreceived-also apparently as a result of the
exhaust pressure-trip-that-wasreceived-also apparently as a result of the


water intrusion. Because the RCIC system was inoperable at-the time of the
water intrusion.
 
Because the RCIC system was inoperable at-the time of the


event, no safety-related high pressure injection system'would have been imme- diately available to restore water level should that have been necessary.
event, no safety-related high pressure injection system'would have been imme- diately available to restore water level should that have been necessary.
Line 131: Line 166:
Perhaps more serious is the potential effect the water could have had on
Perhaps more serious is the potential effect the water could have had on


numerous other safety systems. The ATTS panels have permissive and arming
numerous other safety systems.


===The ATTS panels have permissive and arming===
logic and trip, logic for various safety systems, as well as water level inputs
logic and trip, logic for various safety systems, as well as water level inputs


to the HPCI, RCIC, core spray (CS)., automatic depressurization system (ADS),
to the HPCI, RCIC, core spray (CS)., automatic depressurization system (ADS),
  residual heat removal (RHR) system, and diesel activation logic. It is hard to
residual heat removal (RHR) system, and diesel activation logic.


===It is hard to===
predict the anomalous behavior that could occur if both power supplies had been
predict the anomalous behavior that could occur if both power supplies had been


Line 146: Line 183:
Prior to this event, no procedures were in place at Hatch Unit 1 for adequately
Prior to this event, no procedures were in place at Hatch Unit 1 for adequately


cleaning the ventilation plenums or drains in the charcoal filter units. Had
cleaning the ventilation plenums or drains in the charcoal filter units.
 
Had


these procedures been prepared and implemented, the drain's would have functioned
these procedures been prepared and implemented, the drain's would have functioned


as designed with no serious adverse effects. In response to this event, the
as designed with no serious adverse effects.


===In response to this event, the===
licensee cleaned and inspected drains in the remaining filter units and is
licensee cleaned and inspected drains in the remaining filter units and is


Line 158: Line 198:
schedules.
schedules.


IN 85-85 October 31, 1985 Another example of a design feature which could cause potential adverse system
IN 85-85 October 31, 1985 Another example of a design feature which


interactions was recently found at Unit 1 of the South Texas Project. A non- seismic, non-category I potable water line> was found to pass through the control
interactions was recently found at Unit 1 seismic, non-category I potable water line


room envelope via a relay room next to the> control room. This could subject the
room envelope via a relay room next to the


solid-state protection system cabinets ancI the Westinghouse 7300 process control
solid-state protection system cabinets anc


system located nearby to water damage foll owing a seismic event. Although this
system located nearby to water damage foll


unit is under construction, it does point out that these problems can occur.
unit is under construction, it does point
 
could cause potential adverse system
 
of the South Texas Project. A non-
> was found to pass through the control
 
> control room.
 
===This could subject the===
I the Westinghouse 7300 process control
 
owing a seismic event.
 
===Although this===
out that these problems can occur.


Also, IE Information Notice 83-41, "Actuation of Fire Suppression System
Also, IE Information Notice 83-41, "Actuation of Fire Suppression System
Line 186: Line 241:
listed below.
listed below.


w4ar . Jordan, Director
w4ar


Divis n of Emergency Preparedness
. Jordan, Director


===Divis n of Emergency Preparedness===
and Engineering Response
and Engineering Response


Office of Inspection and Enforcement
===Office of Inspection and Enforcement===


===Technical Contact:===
===Technical Contact:===


===David R. Powell, IE===
===David R. Powell, IE===
                    (301) 492-8373 Attachment:   List of Recently Issued IE Information Notices
(301) 492-8373 Attachment:  
 
===List of Recently Issued IE Information Notices===
 
===Attachment 1===
IN 85-85
 
===October 31, 1985===
LIST OF RECENTLY ISSUED
 
===IE INFORMATION NOTICES===
Information


Attachment 1 IN 85-85 October 31, 1985 LIST OF RECENTLY ISSUED
Date of


IE INFORMATION NOTICES
Notice No.


Information                                  Date of
Subject


Notice No.    Subject                        Issue   Issued to
Issue


85-84          Inadequate Inservice Testing 10/30/85  All power reactor
Issued to


Of Main Steam Isolation Valves          facilities holding
85-84
85-83
85-82
85-81
85-80
Inadequate Inservice Testing 10/30/85


an OL or CP
===Of Main Steam Isolation Valves===
Potential Failures Of General 10/30/85 Electric PK-2 Test Blocks
 
Diesel Generator Differen-
10/18/85 tial Protection Relay Not
 
===Seismically Qualified===
Problems Resulting In
 
10/17/85
 
===Erroneously High Reading===
With Panasonic 800 Series
 
===Thermoluminescent Dosimeters===
Timely Declaration Of An
 
10/15/85 Emergency Class Implemienta- tion Of An Emergency Plan,
 
===And Emergency Notifications===
Possible Sticking Of ASCO


85-83          Potential Failures Of General 10/30/85 All power reactor
10/1/85


Electric PK-2 Test Blocks              facilities holding
===Solenoid Valves===
Inadequate Communications


an OL or CP
9/30/85 Between Maintenance,


85-82          Diesel Generator Differen-    10/18/85 All power reactor
===Operations, And Security===
Personnel


tial Protection Relay Not              facilities holding
Event Notification


Seismically Qualified                  an OL or CP
9/23/85


85-81          Problems Resulting In          10/17/85 All power reactor
===All power reactor===
facilities holding


Erroneously High Reading                facilities holding
an OL or CP


With Panasonic 800 Series              an OL or CP and
===All power reactor===
facilities holding


Thermoluminescent Dosimeters            certain material
an OL or CP


and fuel cycle
===All power reactor===
facilities holding


licensees
an OL or CP


85-80          Timely Declaration Of An      10/15/85 All power reactor
===All power reactor===
facilities holding


Emergency Class Implemienta-            facilities holding
an OL or CP and


tion Of An Emergency Plan,              an OL or CP
certain material


And Emergency Notifications
and fuel cycle


85-17          Possible Sticking Of ASCO      10/1/85  All power reactor
licensees


Sup. 1        Solenoid Valves                        facilities holding
===All power reactor===
facilities holding


an OL or CP
an OL or CP


85-79          Inadequate Communications    9/30/85  All power reactor
===All power reactor===
facilities holding
 
an OL or CP


Between Maintenance,                    facilities holding
===All power reactor===
facilities holding


Operations, And Security                an OL or CP; research
an OL or CP; research


Personnel                              and nonpower reactor
and nonpower reactor


facilities; fuel
facilities; fuel
Line 265: Line 368:
processing facilities
processing facilities


85-78          Event Notification            9/23/85  All power reactor
===All power reactor===
 
facilities holding
facilities holding


an OL or CP
an OL or CP


OL = Operating License
85-17 Sup. 1
85-79
85-78 OL = Operating License


CP = Construction Permit}}
CP = Construction Permit}}


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

Latest revision as of 10:25, 16 January 2025

Systems Interaction Event Resulting in Reactor System Safety Relief Valve Opening Following a Fire-Protection Deluge System Malfunction
ML031180210
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, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, 05000000, Zimmer, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant, Skagit, Marble Hill, Crane
Issue date: 10/31/1985
From: Jordan E
NRC/IE
To:
References
IN-85-085, NUDOCS 8510290039
Download: ML031180210 (4)
v • d • e


SSINS No.:

6835 IN 85-85

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF INSPECTION AND ENFORCEMENT

WASHINGTON, D.C.

20555

October 31, 1985

IE INFORMATION NOTICE 85-85:

SYSTEMS INTERACTION EVENT RESULTING IN REACTOR

SYSTEM SAFETY RELIEF VALVE OPENING FOLLOWING

A FIRE-PROTECTION DELUGE SYSTEM MALFUNCTION

Addressees

All nuclear power reactor facilities holding an operating license (OL) or a

construction permit (CP).

Purpose

This notice is provided to alert licensees of a serious systems interaction

event involving the fire-protection deluge system located in the control room

ventilation charcoal filter housing.

Following inadvertent actuation of this

system, an analog transient trip system (ATTS) panel was sprayed with water

causing malfunctions in certain safety system components.

It is expected that recipients will review this notice for applicability to

their facilities and consider actions, if appropriate, to preclude a similar

problem occurring at their facilities.

However, suggestions contained in this

notice do not constitute requirements; therefore, no specific action or written

response is required.

Description of Circumstances

On May 15, 1985, at Georgia Power Company's Hatch Unit 1, personnel manually

scrammed the reactor from 75% power because of a stuck open low-low-set safety

relief valve (LLS-SRV).

Shorting of one of the two redundant power supplies

and/or possibly intermittent shorting of logic system contacts in the ATTS

panel is believed to have caused the stuck open LLS-SRV. The panel is one of

two redundant panels located in the control room.

The cause of the electrical

shorts in the affected panel was water intrusion into the panel.

The event began about 8:35 p.m. when an instrument water supply vent valve was

damaged, apparently by dragging of a crane hook along the line.

The instru- ment water supply line eventually depressurized causing a portion of the fire- protection deluge system to actuate. The water supply line is located above

the control building and the deluge system is located in the control room

charcoal filter housing.

Following actuation of the deluge system, approximately 15 to 25 gal of water

backed up into the ventilation header before the system could be secured.

The

8510290039

IN 85-85 October 31, 1985 backup was caused by plugged drains in the charcoal filter housing.

Water

eventually leaked through a hole in the ventilation piping that was located

above the ATTS panel in the control room. Whenthe water sprayed onto the panel, one of two redundant panel power supplies apparently shorted because of water

intrusion into the panel.

As a result, a LLS-SRV valve began to cycle open and

closed.

The SRV cycled three t imes and then opened and remained open.

The

operator manually scrammed the reactor from 75% power. A false turbine high

exhaust pressure trip signal also was generated, temporarily disabling the high

pressure core injection (HPCI) system.

The reactor core isolation cooling

(RCIC) system was inoperable at the time, so neither HPCI nor RCIC was imme- diately available for use.

Fortunately, neither system was needed during the

event.

This is because the water level was restored and maintained by the

reactor feedwater system until the MSIVs were shut.

Subsequent to MSIV closure, water level was maintained by the control rod drive (CRD) system with the

excess water being dumped to the condenser via the reactor-water cleanup-system.

The LLS-SRV closed without operator action at 9:52 pm.

Discussion:

The event is of considerable concern because of the potential for multiple

safety system failures through unanalyzed systems interactions.

In this event, the water from the fire-suppression deluge system in the control room caused

opening of a safety relief valve and loss of primary system inventory.

The

event could have been seriously aggravated by the spurious HPCI turbine high

exhaust pressure-trip-that-wasreceived-also apparently as a result of the

water intrusion.

Because the RCIC system was inoperable at-the time of the

event, no safety-related high pressure injection system'would have been imme- diately available to restore water level should that have been necessary.

The HPCI turbine trip signal was reset shortly after it occurred, however, and

the system was returned to operability.

Perhaps more serious is the potential effect the water could have had on

numerous other safety systems.

The ATTS panels have permissive and arming

logic and trip, logic for various safety systems, as well as water level inputs

to the HPCI, RCIC, core spray (CS)., automatic depressurization system (ADS),

residual heat removal (RHR) system, and diesel activation logic.

It is hard to

predict the anomalous behavior that could occur if both power supplies had been

lost, or if other portions of the logic had been shorted; but quite possibly, several safety systems could have malfunctioned, seriously handicapping the

operators during their efforts to stabilize the unit.

Prior to this event, no procedures were in place at Hatch Unit 1 for adequately

cleaning the ventilation plenums or drains in the charcoal filter units.

Had

these procedures been prepared and implemented, the drain's would have functioned

as designed with no serious adverse effects.

In response to this event, the

licensee cleaned and inspected drains in the remaining filter units and is

preparing cleanout and inspection procedures to be added to the maintenance

schedules.

IN 85-85 October 31, 1985 Another example of a design feature which

interactions was recently found at Unit 1 seismic, non-category I potable water line

room envelope via a relay room next to the

solid-state protection system cabinets anc

system located nearby to water damage foll

unit is under construction, it does point

could cause potential adverse system

of the South Texas Project. A non-

> was found to pass through the control

> control room.

This could subject the

I the Westinghouse 7300 process control

owing a seismic event.

Although this

out that these problems can occur.

Also, IE Information Notice 83-41, "Actuation of Fire Suppression System

Causing Inoperability of Safety Related Equipment," was issued on June 22, 1983.

That notice identified a number of instances in which automatic actuation of

fire suppression systems degraded or jeopardized the operability of safety- related equipment.

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

If you have any questions regarding this matter, please contact the Regional

Administrator of the appropriate NRC regional office or the technical contact

listed below.

w4ar

. Jordan, Director

Divis n of Emergency Preparedness

and Engineering Response

Office of Inspection and Enforcement

Technical Contact:

David R. Powell, IE

(301) 492-8373 Attachment:

List of Recently Issued IE Information Notices

Attachment 1

IN 85-85

October 31, 1985

LIST OF RECENTLY ISSUED

IE INFORMATION NOTICES

Information

Date of

Notice No.

Subject

Issue

Issued to

85-84

85-83

85-82

85-81

85-80

Inadequate Inservice Testing 10/30/85

Of Main Steam Isolation Valves

Potential Failures Of General 10/30/85 Electric PK-2 Test Blocks

Diesel Generator Differen-

10/18/85 tial Protection Relay Not

Seismically Qualified

Problems Resulting In

10/17/85

Erroneously High Reading

With Panasonic 800 Series

Thermoluminescent Dosimeters

Timely Declaration Of An

10/15/85 Emergency Class Implemienta- tion Of An Emergency Plan,

And Emergency Notifications

Possible Sticking Of ASCO

10/1/85

Solenoid Valves

Inadequate Communications

9/30/85 Between Maintenance,

Operations, And Security

Personnel

Event Notification

9/23/85

All power reactor

facilities holding

an OL or CP

All power reactor

facilities holding

an OL or CP

All power reactor

facilities holding

an OL or CP

All power reactor

facilities holding

an OL or CP and

certain material

and fuel cycle

licensees

All power reactor

facilities holding

an OL or CP

All power reactor

facilities holding

an OL or CP

All power reactor

facilities holding

an OL or CP; research

and nonpower reactor

facilities; fuel

fabrication and

processing facilities

All power reactor

facilities holding

an OL or CP

85-17 Sup. 1

85-79

85-78 OL = Operating License

CP = Construction Permit


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