Information Notice 1989-36, Excessive Temperatures in Emergency Core Cooling System Piping Located Outside Containment

Excessive Temperatures in Emergency Core Cooling System Piping Located Outside Containment

ML031180787
Person / Time
Site:	Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Mcguire, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Three Mile Island, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, 05000000, Zimmer, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant
Issue date:	04/04/1989
From:	Rossi C Office of Nuclear Reactor Regulation
To:
References
IN-89-036, NUDOCS 8903290256
Download: ML031180787 (7)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 April 4, 1989 NRC INFORMATION NOTICE: NO. 89-36: EXCESSIVE TEMPERATURES IN EMERGENCY

CORE COOLING SYSTEM PIPING LOCATED

OUTSIDE CONTAINMENT

Addressees

All holders of operating licenses or construction permits for nuclear power

reactors.

Purpose

This information notice is being provided to alert addressees to an event that

involved the potential for reactor coolant system (RCS) leakage outside con- tainment. A check valve serving as the inboard containment isolation valve

in a high-pressure injection (HPI) system injection line failed to seat pro- perly after termination of HPI flow, allowing RCS backflow into HPI system

piping that was not qualified for RCS temperatures. The HPI system piping

was exposed to fluid temperatures in excess of design temperatures, resulting

in stresses that exceeded the allowable limits for Class 1 piping according

to the American Society of Mechanical Engineers Boiler and Pressure Vessel

Code (ASME Code),Section III. Recipients are expected to review the infor- mation for applicability to their facilities and consider actions, as appro- priate, to avoid similar problems. However, suggestions contained in this

information notice do not constitute NRC requirements; therefore, no specific

action or written response is required.

Description of Circumstances

On January 20, 1989, at Arkansas Nuclear One, Unit 1 (ANO-1), a failure of the

main generator exciter resultedin a generator lockout and subsequent trips of

the main turbine and the reactor. Upon loss of power to plant loads from the

main generator, one of the two non-safety-related 6.9 kV buses failed to auto- matically fast transfer from the unit auxiliary transformer to the startup

transformer; this failure caused two of the four reactor coolant pumps (RCPs)

to trip on undervoltage. A failure of one of the main feedwater (MFW) pumps

to runback to minimum speed and a failure of a MFW block valve and control

valves to close after the reactor trip resulted in overfeed of the once through

steam generators; this overfeed caused a slight overcooling (110F) of the RCS.

The operators manually started one HPI system pump to maintain pressurizer

level above the heater cutoff point. The pump was secured 2 minutes later;

however, check valve MU-34B in the "B" HPI line did not seat pfoperly (see

Figure 1). The existing RCP configuration (i.e., two pumps r nning and two

I 8903290256

IN 89-36 April 4, 1989 pumps tripped) created a differential pressure across MU-34B

backflow into the HPI system piping outside containment. that caused RCS

from the RCS and outside containment via MU-34B, through The flow path ran

the crossover pipe

to the "C" HPI line, and then back Inside containment to

as shown in Figure 1. The HPI system piping upstream of the RCS via MU-34C

lified for RCS temperatures. Subsequent analysis by the MU-34B was not qua- a RCS temperature of 5450 F) showed that the temperature licensee (assuming

effects resulted in

stresses that exceeded ASME code-allowable limits for Class

HP! system piping was qualified for RCS pressure but was 1 piping. The

only designed for

a temperature of 1450 F. The licensee became aware of RCS

containment when tape attached to the HPI piping began to leakage outside

smoke, activating a local smoke detector and the associatedmelt, smolder and

control room alarm.

Discussion:

The primary concerns are that the failure of a check valve

to seat properly ex- posed piping located outside containment to RCS temperature

was not designed for RCS temperatures. Furthermore, the and that the piping

the Inboard containment isolation valve, but valve testingcheck valve serves as

Inspection and vertical stroke of the valve disc) was not (consisting of visual

excessive wear problem that led to its failure. Because adequate to reveal the

tainment was not monitored to detect RCS in-leakage (e.g.,the piping outside con- high temperature

alarms), the piping potentially could be exposed to RCS temperatures

periods without being detected. It is important for addressees for long

for piping to be qualified for potential inservice conditions to note the need

sociated components, that are part of the reactor coolant and that the as- subject to applicable ASME Code requirements which include, pressure boundary, are

in part, leak

detection, isolation and periodic testing.

Corrective actions proposed by the licensee include installation

check valve in each HPI line inside containment, installation of a second

of

monitoring instrumentation in the HP! lines outside containment temperature- containment penetration and the first outboard check valve, between the

all piping that was determined to be overstressed from high replacement of

the event, and leak rate testing for all check valves in temperature during

the HPI lines inside

containment.

Subsequent review by the licensee identified HPI system

are not Qualified for the maximum temperature to which thepipe supports that

could be exposed when the HPI system is used in the piggyback associated piping

The licensee is upgrading the pipe supports. It is important mode of operation.

be analyzed and qualified for the maximum temperature and that system piping

could be exposed, regardless of whether credit is given in pressure to which It

the final safety

analysis report (FSAR) transient/accident analysis for the

of operation. associated mode

IN 89-36 April 4, 1989 No specific action or written response is required by this information notice.

If you have any questions about this matter, please contact one of the technical

contacts listed below or the Regional Administrator of the appropriate regional

office.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: Rick Kendall, NRR

(301) 492-3140

Yueh-Li Li, NRR

(301) 492-0915 Attachments:

1. Figure 1 - ANO High Pressure Injection System Flow Path to the Reactor

Coolant System (Simplified Diagram)

2. List of Recently Issued NRC Information Notices

FIGURE 1 - ANO-1 HIGH PRESSURE INJECTION SYSTEM FLOW PATH TO

THE REACTOR COOLANT SYSTEM (SIMPLIFIED DIAGRAM)

OTSG

OTSG

HIGH

PRESSURE

INJECTION

PUMPS a.-> >

CD

M -..-- CoC+)~0)

- to 0

-h_ I 3

-' '.

REACTOR ~ o

C+

f.0

COOLANT

PUMPS

Attachment 2 IN 89-36 April 4, 1989 *I LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information Date of

Notice No. Subject Issuance Issued to

88-86, Operating with Multiple 3/31/89 All holders of OLs

Supp. 1 Grounds in Direct Current or CPs for nuclear

Distribution Systems power reactors.

89-35 Loss and Theft of Un- 3/30/89 All U.S. NRC byproduct, secured Licensed Material source and special

nuclear material

licensees.

89-34 Disposal of Americium 3/30/89 All holders of an

Well-Logging Sources NRC specific license

authorizing well- logging activities.

89-33 Potential Failure of 3/23/89 All holders of OLs

Westinghouse Steam or CPs for PWRs.

Generator Tube

Mechanical Plugs

89-32 Surveillance Testing 3/23/89 All holders of OLs

of Low-Temperature or CPs for PWRs.

Overpressure-Protection

Systems

89-31 Swelling and Cracking 3/22/89 All holders of OLs

of Hafnium Control Rods or CPs for PWRs with

Hafnium control rods.

89-30 High Temperature 3/15/89 All holders of OLs

Environments at or CPs for nuclear

Nuclear Power Plants power reactors.

89-29 Potential Failure of 3/15/89 All holders of OLs

ASEA Brown Boveri or CPs for nuclear

Circuit Breakers power reactors.

During Seismic Event

89-28 Weight and Center of 3/14/89 All holders of OLs

Gravity Discrepancies or CPs for nuclear

for Copes-Vulcan power reactors.

Air-Operated Valves

OL = Operating License

CP = Construction Permit

IN 89-36 April 4, 1989 No specific action or written response is required by this information notice.

If you have any questions about this matter, please contact one of the technical

contacts listed below or the Regional Administrator of the appropriate regional

office.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: Rick Kendall, NRR

(301) 492-3140

Yueh-Li Li, NRR

(301) 492-0915 Attachments:

1. Figure 1 - ANO High Pressure Injection System Flow Path to the Reactor

Coolant System (Simplified Diagram)

2. List of Recently Issued NRC Information Notices

• SEE PREVIOUS CONCURRENCE

5FC  :*EAB:NRR  :*EAB:NRR  :*TECH:ED  :*C:EMEB:DEST:*C:EAB:NRR  :*C:OGCB:NRR :D:DOEA:NRR

NAME :RKendall:db :RLobel :TMarsh :WDLanning / :

CHBerlinger

DATE :3/16/89 :3/22/89  : 3/16/89 :3/24/89 :3/29/89 :3/29 /89 :3 /89 OFFICIAL RECORD COPY

IN 89- March , 1989 No specific action or written response is required by this information notice.

If you have any questions about this matter, please contact one of the technical

contacts listed below or the Regional Administrator of the appropriate regional

office.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: Rick Kendall, NRR

(301) 492-3140

Yueh-Li Li, NRR

(301) 492-0915 Attachments:

1. Figure 1 - ANO High Pressure Injection System Flow Path to the Reactor

Coolant System (Simplified Diagram)

2. List of Recently Issued NRC Information Notices

• SEE PREVIOUS NCURRENCE c2m

OFC :EAB:hNF.K/V :EAB:N K  :*TECH:EUD -:C-:EMEB:DEST :C:EA:R C:WCAVW :D:DOEA:NRR

_ -__-___-_ A---:------------ ------------ :------------:-:b ti ---:~~~~--------- -----------

NAME :RKendall:db :RLobel  : :Tlarsh :W nning :CHBerlinger :CERossi

DATE 0316/6/89 - /X./89  : / 89 /2 /89

/$%/89  :^

• /89/89  : / /89 OFFICIAL RECORD COPY