Information Notice 1990-28, Potential Error in High Steamline Flow Setpoint

Potential Error in High Steamline Flow Setpoint

ML031130248
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, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant, Crane
Issue date:	04/30/1990
From:	Rossi C Office of Nuclear Reactor Regulation
To:
References
IN-90-028, NUDOCS 9004240359
Download: ML031130248 (7)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555

April 30, 1990

NRC INFORMATION NOTICE NO. 90-28: POTENTIAL ERROR IN HIGH STEAMLINE

Addressees

All holders of operating licenses or-construction permits for boiling water

reactors (BWRs).

Purpose

This information notice is intended to alert addressees to possible errors in

the method used to determine the proper setpoints.for-the steamline flow dif- ferential pressure instruments that initiate isolation of the High Pressure

Coolant Injection (HPCI) and Reactor Core Isolation Cooling (RCIC) systems

at a limit corresponding to a specific percentage of the rated steam flow.

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 November 30, 1989, during a.surveillance test of the HPCI system at the

FitzPatrick Nuclear Power Plant, automatic isolation of the steam admission

valves on high steamline flow occurred (Docket No. 50-333; LER No. 89-025-00).

An-intensive series.of tests was initiated to identify the root cause of this

event. To perform these tests, additional instrumentation was connected to

the steamline flow instruments to determine the differential pressure detected

by the instrumentation. This testing led to the determination that the signal

that resulted from startup of the turbine was close to the Isolation setpoint

and, in some cases, was greater than the setpoint. Because the isolation set- point was in accordance with the value specified in the technical specifications, and because no leakage or reason for a high-flow condition could be found, a

possible problem either with the value specified for the setpoint or with the

amount of steam needed to start the turbine, or both, was identified.

Discussion:

At FitzPatrick, the HPCI system is a steam turbine driven Emergency Core

Cooling System designed to supply makeup water to the reactor vessel in

900420359-

K)-

IN 90-28 April 30, 1990 the event of a loss-of-coolant accident. The high steam flow isolation of

the HPCI turbine is designed to shut the steamline isolation valves to the

turbine if the steam supply piping ruptures.

At FitzPatrick, this.flow signal

is derived by sensing the differential pressure that results from flow through

the steam supply piping at an elbow in the piping. If this differential

pressure, expressed in inches of water, reaches the value given in the tech- nical specifications, the isolation valves close.

The accepted value of steam flow that indicates that a break in the steam- line has occurred is typically 300 percent of the rated steam flow.

The

determination of the differential pressure that corresponds to this flow, and hence the Indication that a steamline break has occurred is the subject

of General Electric Nuclear Services Information Letter (SILI No. 475.* The

analytic method described in the SIL applies to HPCI and RCIC systems and uses

measured data from the as-built system operating under rated conditions in the

surveillance test mode, rather than using purely theoreticaltanalysis, to

calculate the differential pressure that would exist at 300-percent flow.

This differential pressure then becomes the setpoint for the switch that

initiates isolation of the system. However, other methods based on sound

engineering principles may also be appropriate.

At FitzPatrick, as part of the root cause determination, the intensive series

of tests found that the actual differential pressure setpoint that caused the

l1solati on

nniurresspned-tu approx-imately-200-pereent-flow, -an--that-the-staxtup--

of the HPCI system occasionally caused the flow to reach this value.

Such a

setpoint is conservative from the viewpoint of the safety function of the high

steamline flow trip, but it adversely affects the reliability of the HPCI

system. Performing the calculations in accordance with SIL No. 475 resulted

in the removal of this conservatism from the setpoint and in the restoration

of the reliability of the HPCI system.

The HPCI system had operated with the setpoint conservatism for 14 years until

several recent changes were made to the system. These changes Included test

methodology improvements, hydraulic actuator replacement (which resulted in

the need for additional steam for turbine startup), and turbine stop valve

rewiring. Setting the setpoint according to Revision 2 of SIL No. 475 pro- vides the proper value for initiation of the Isolation function.

• Revision 2 of SIL No. 475 was issued November 28, 1988, by the General

Electric Company, San Jose, California.

As noted in Revision 2, errors in

the original and in Revision I have been corrected in Revision 2.

IN 90-28 i:

April 30, 1990 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 NRR project manager.

Charles E. ossl, Director

Division of Operational Events Assessment

D. LaBarge, NRR

(301) 492-1421 Attachment: List of Recently Issued NRC Information Notices

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Attachment

AIN 90-N8 prIl 30, 1990

Page I of I

LIST OF RECENTLYV

ISSUED

NRC INF0RHATIhN

NOTICES

Insormatuon

Date or

Hotie No.

Subeet

Issuance

Issued to

90-27 Clarification of the

4130/90

All uranium fuel

Recent Revisions to the

fabrication and

Regulatory Requirments

conversion facilities

for Packaging of Urnnium

Nexafluords

41.

l)

for

Transportation

S9W70,

Possible Indications of

4/26/90

All holders of OLs

Supp. I

MisrepresenUted Vendor

or CPs for nuclear

Products

power reactors.

90-26 Inadequate Flow of

4/24/90

All holders of OLs

Essential Service Water

or CPs for nuclear

to Rooe Coolers end Heat

power reectors.

Exchangers for Engineered

Safety-Feature Systeme

90-25 Lost of Vital AC Power

4/16o90

All holders of OLs

with Subsequeit Reactor

or CPs for nuclear

coolent Systee Heat-Up

power reactors.

90-24 Transportation of Model

4/10/90

All NRC licensees

Spec 2-T Radiographic

authorized to use.

Exposure Device

transport, or operate

radiographic exposure

- devices and source

changers..

90-29 Improper Installation of

4/4/90

All holders of OLs

Patel Conduit Seals

or CPs for nuclear

power reactors.

90-22 Unenticipoted Equipuent

3/23/90

All holders

of Ohs

Actuations Fellowing

or CPs for nuclear

Restoration of Power

power reactors

to Rosemeust Transmitter

Trip Units

90-21 Potential Failure of Motor-

3/22/90

All holders of OLs

Operated Butterfly Valves

or CPs for nuclear

to Operate Because Valve

power reactors.

Seat Friction was Under- stistted

0L

• Operating License

CP

• Construction Permit

UNITED STATES

NUCLEAR REGULATORY COMMISSION

WASHINGTON, D.C. 20555

OFFICIAL BUSINESS

PENALTY FOR PRIVATE USE, $300

FIRST CLASS MAIL

POSTAGE b FEES PAID

USNRC

PERMIT No. 5 E7

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IN 90-28

April 30, 1990 This information notice requires i

you have any questions about the 1 technical contact listed below or

io specific action or written response. If

Information in this notice, please contact the

the appropriate NRR project manager.

Charles E. Rossi, Director

Division of Operational Events Assessment

D. LaBarge, NRR

(301) 492-1421 Attachment: List of Recently Issued NRC Information Notices

Document Name:

INFO NOTICE - LABARGE, KADAMBI

• SEE PREVIOUS CONCURRENCES

• OGCB:DOEA:NRR*PD11:DRP:NRR

NPKadambi

DLaBarge

03/28/90

04/03/90

• RPB:ADM

TechEd

04/17/90

• C/OGCB:DOEA:NRR

CHBerlinger

04/20/90

IN 90-XX

April xx, 1990 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 NRR project manager.

Charles E. Rossi, Director

Division of Operational Events Assessment

Technical Contact:

D. LaBarge

(301) 492-1421 Attachment: List of Recently Issued NRC Information Notices

Document Name:

INFO NOTICE - LABARGE, I

• SEE PREVIOUS CONCURRENCES

• OGCB:DOEA:NRR*PD11:DRP:NRR

NPKadambi

DiaBarge

03/28/90

04/03/90

4/4~10

• RPB:ADM

TechEd

04/17/90

(ADAMB I

C/O 'B~$~RRI

CHB r

gerI

04/X/90

1 D/DOEA:NRR

CERossi

04/ /90

IN 90-XX

March xx, 1990 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 NRR project manager.

Charles E. Rossi, Director

Division of Operational Events Assessment

Technical Contact:

D. LaBarge

(301) 492-1421 Attachment:

List of Recently Issued NRC Information Notices

1 V'

t Nm- NO

I

It Name:} INFO NOTICE - LABARGE, KADAMBI

NPKadambi

03/M/90

NRR PD11:DRP:

DLaBargec

0//S /90

RPB :ADM

TechEd-j4

03/ /90

fl17/W

C/OGCB:DOEA:NRR

CHBerlinger

03/ /90

D/DOEA:NRR

CERossi

03/ /90