Information Notice 1989-41, Operator Response to Pressurization of Low-Pressure Interfacing Systems

Operator Response to Pressurization of Low-Pressure Interfacing Systems

ML031180816
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:	04/20/1989
From:	Rossi C Office of Nuclear Reactor Regulation
To:
References
IN-89-041, NUDOCS 8904140042
Download: ML031180816 (6)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 April 20, 1989 NRC INFORMATION NOTICE NO. 89-41: OPERATOR RESPONSE TO PRESSURIZATION

OF LOW-PRESSURE INTERFACING SYSTEMS

Addressees

All holders of operating licenses or construction permits for nuclear power

reactors.

Purpose

This information notice is being provided to alert addressees to potential

problems that may arise from the lack of proper procedures to deal with un- expected pressurization of systems designed for low operating pressure such

as the residual heat removal (RHR) 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 do not constitute NRC requirements;

therefore, no specific action or written response is required.

Description of Circumstances

On March 9, 1989, when Vogtle Unit 2 was in Mode 3 preparing for initial

criticality, the reactor coolant system (RCS) leakage exceeded Technical

Specification limits. The leakage was observed during a surveillance test

on a cold-leg swing check valve that acts as the inboard pressure isolation

boundary between the RCS and the low-pressure RHR system. The RHR system

had been taken out of service, but the pressure in it did not reduce to the

expected level. To relieve the RHR system pressure, operators opened two

normally locked-closed valves that connect the RHR system to the refueling

water storage tank (RWST), thereby venting RCS coolant to the tank, and from

there, to the atmosphere. The action they took to depressurize the RHR system

was inappropriate and taken without the benefit of proper procedures.

Subsequent investigations determined that the inboard cold-leg check valve in

question had experienced abnormal wear. The operators appear to have considered

possible leakage into the RHR.system, such as leakage through check valves and

through isolation valves from the chemical and volume control system. However, the action taken did not reflect an awareness of the potential seriousness of

such leakage.

8904140042 7.ZA--

IN 89-41 April 20, 1989 Discussion:

During this event, public safety was not adversely affected at Vogtle Unit 2 because there was no fission product inventory in the reactor. Also, the

potential for damage to the RHR system was minimal because the leakage was

well within the relieving capacity of the systemi. However, leakage of RCS

coolant into systems such as the RHR system and responses to such events by

operators have been sources of longstanding concern because of the potential

for the so-called "Event V" or the "interfacing system loss-of-coolant ac- cident." It is important that licensees have proper procedures that will

enable operators to take only appropriate actions to respond to unexpected

or unexplained pressurization of systems such as the RHR system.

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

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

contact listed below or the Regional Administrator of the appropriate regional

office.

s.Director  :

Division of Operational Events Assessment

Office-of-Nuclear- Reactor Regulation---

N. Prasad Kadambi, NRR

(301) 492-1153 Attachment: List of Recently Issued NRC Information Notices

Attachment

IN 89-41 April 20, 1989 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information Date of

Notice No. Subject Issuance Issued to

88-75, Disabling of Diesel 4/17/89 All holders of OLs

Supplement 1 Generator Output Circuit or CPs for nuclear

Breakers by Anti-Pump power reactors.

Circuitry

89-40 Unsatisfactory Operator Test 4/14/89 All holders of OLs

Results and Their Effect on or CPs for nuclear

the Requalification Program power reactors.

89-39 List of Parties Excluded 4/5/89 All holders of OLs

from Federal Procurement or CPs for nuclear

or Non-Procurement Programs power reactors.

89-38 Atmospheric Dump Valve 4/5/89 All holders of OLs

Failures at Palo Verde or CPs for nuclear

Units 1, 2, and 3 power reactors.

89-37 Proposed Amendments to 4/4/89 All U.S. NRC licensees.

40 CFR Part 61, Air

Emission Standards

for Radionuclides

89-36 Excessive Temperatures 4/4/89 All holders of OLs

in Emergency Core Cooling or CPs for nuclear

System Piping Located power reactors.

Outside Containment

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.

OL = Operating License

CP = Construction Permit

IN 89-41 April 20, 1989 Discussion:

Unit 2 During this event, public safety was not adversely affected at Vogtle the

in the reactor. Also, because there was no fission product inventory leakage was

potential for damage to the RHR system was minimal because the leakage of RCS

well within the relieving capacity of the system. However, and responses to such events by

coolant into systems such as the RHR system the potential

operators have been sources of longstanding concern because of

ac- for the so-called "Event V" or the "interfacing system loss-of-coolant that will

cident." It is important that licensees have proper procedures

unexpected

enable operators to take only appropriate actions to respond to

or unexplained pressurization of systems such as the RHR system.

notice.

No specific action or written response is required by this informationtechnical

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

regional

contact listed below or the Regional Administrator of the appropriate

office.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

N. Prasad Kadambi, NRR

(301) 492-1153 Attachment: List of Recently Issued NRC Information Notices

• SEE PREVIOUS CONCURRENCES

• OGCB: DOEA:NRR *C/SRXB:DEST: NRR *RPB:ARM *C/OGCB:DOEA:NRR

NPKadambi MWHodges TechEd CHBerlinger

04/13/89 04//9189

04/04/89 04/04/89 04/05/89

IN 89-XX

April xx, 1989 Discussion:

During this event, public safety was not adversely affected at Vogtle Unit 2 because there was no fission product inventory in the reactor. Also, the

potential for damage to the RHR system was minimal because the leakage was well

within the relieving capacity of the system. However, leakage of RCS coolant

into systems such as the RHR system and responses to such events by operators

have been sources of longstanding concern because of the potential for the

so-called "Event VI' or the "interfacing system loss-of-coolant accident. It is

important that licensees develop proper procedures that will enable operators

to take only appropriate actions to respond to unexpected or unexplained

pressurization of systems such as the RHR system.

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

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

contact 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

N. Prasad Kadambi, NRR

(301) 492-1153 Attachment: List of Recently Issued NRC Information Notices

• W/PREVIOUS CONCURRENCES

• OGCB: DOEA:NRR *C/SRXB:DEST:NRR *RPB:ARM C/OGCB:DOEA:NRR D/DOEA:NRR

NPKadambi MWHodges TechEd CHBerlinger CERossi

04/04/89 04/04/89 04/05/89 04//3/89 04/ /89 iq qsl .

IN 89-XX

April xx, 1989 Discussion:

Public safety was not adversely affected at Vogtle Unit 2 because there was no

fission product inventory in the reactor. Also, the potential for damage to

the RHR system was minimal because the leakage was well within the relieving

capacity of the system. However, leakage of RCS coolant into systems such as

the RHR system and responses to such events by operators have been sources of

long standing concern because of the potential for the so-called "Event VI' or

the "interfacing system LOCA." It is important that licensees develop proper

procedures which will enable operators to take only appropriate actions to

respond to unexpected and unexplained pressurization of systems such as the RHR

system.

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

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

contact 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

N. Prasad Kadambi, NRR

(301) 492-1153 Attachment: List of Recently Issued NRC Information Notices

bPK

OGCB:DOEA:NRR C/S DEST:NRR C/OGCB:DOEA:NRR D/DOEA:NRR

NPKadambi MWHodges 0echEd CHBerlinger CERossi

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