Information Notice 1990-65, Recent Orifice Plant Problems

Recent Orifice Plant Problems

ML031130240
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, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant
Issue date:	10/05/1990
From:	Rossi C Office of Nuclear Reactor Regulation
To:
References
IN-90-065, NUDOCS 9009280166
Download: ML031130240 (10)

UNITED STATES NUCLEAR REGULATORY

COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 October 5, 1990 NRC INFORMATION

NOTICE NO. 90-65: RECENT ORIFICE PLATE PROBLEMS

Addressees

All holders of operating

licenses or construction

permits for nuclear power reactors.

Purpose

This information

notice is intended to alert addressees

to recent problems that have been identified

with orifice plates. 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:

Recent licensee and NRC inspections

have identified

two problems associated

with orifice plates. Namely, the installation

of orifice plates in the reverse direction

and the deformation

of orifices in the direction

of flow.With respect to the first of the two problems, on August 8, 1988, operators

at the San Onofre Nuclear Generating

Station, Unit 1, discovered-an

error in several daily calorimetric

power calibrations.

Further investigation

revealed that one of the three feedwater

flow indicators

was providing

flow indication

that was lower than the actual feedwater

flow. This error resulted in the indicated

power on the nuclear instrumentation

system being adjusted as much as four percent lower than the actual reactor power. The licensee determined

that the orifice plate for the deficient

flow indicator

was installed

backwards, causing the indicated

flow to be less than the actual flow. Subsequent

evaluation

showed that all accident scenarios

described

in the Final Safety Analysis Report produced acceptable

results despite the error. In 1985, San Onofre Unit 1 reported a similar event (LER 50-206/85-014).

During an NRC walkdown of the containment

spray system at the Farley Nuclear Plant in April 1989, inspectors

found that an orifice plate in a flow element had been installed

backwards.

The flow element provided spray additive tank flow indication

in the control room. The licensee subsequently

found four other orifice plates, used in the charging system, the auxiliary

feedwater system, and the containment

spray system, that were reversed.

Similarly, in July 1989 the Shearon Harris Nuclear Power Plant found a reversed orifice plate. This orifice plate also was used to determine

the flow rate for the containment

spray system spray additive tank.( < O 9 2 8 1 6 6 v 7C

IN 90-65 October 5, 1990 Reversed orifice plates have also been found at the Salem Nuclear Generat-ing Station, Brunswick

Steam Electric Plant, Waterford

Steam Electric Plant, Surry Power Station, and North Anna Power Station. At the Salem plant, in May 1989, the flow metering orifices for the high-head

cold leg safety injection line were found installed

backwards.

After the orifices were correctly installed, the indicated

flow rate was 15 percent greater. At Brunswick, in February 1989, the licensee discovered

a flow restricting

orifice installed backwards

in the high-pressure

core injection

minimum flow line, and in two other systems. Waterford

experienced

problems with low indicated

flow in the recirculation

line of a high pressure safety injection

pump. The problem was traced to a reversed flow orifice in May 1989. At Surry in August 1989, an NRC inspector

discovered

a reversed flow orifice after the completion

of a corrective

action program aimed at flow orifices.

Further walkdowns

by the licensee identified

two additional

flow orifices installed

backwards.

At North Anna in September

1989, a total of nine flow orifices were determined

to be installed backwards.

Only orifices which are accessible

during power operation

were inspected.

The root cause of these events has generally

been determined

to be inadequate

procedures

for and inspection

of installations.

In February 1989, a second problem with orifice plates was identified

at Brunswick, i.e., several flow restricting

orifices were deformed in the direc-tion of flow. The orifices were located in the residual heat removal system, the core spray injection

and minimum flow line, and the high-pressure

coolant injection

system. Each of the orifice plates was manufactured

from A240-316-statless-steel-arnd-was

8-inch-thik-

_ltisth-icknes-Swas

based on standard orifice design that did not consider the thickness

needed to prevent deforma-tion caused by flow and the differential

pressure across the orifice plate.In one instance, the orifice bore had increased

from 1.021 inches to 1.088 inches, and the plate had ballooned

outward approximately

0.5 inch. Subse-quently, the licensee evaluated

the design of the orifice plates using allow-able material stresses, orifice plate geometric

configurations, and system flow rates. The results of this evaluation

indicated

that the applied stress exceeded several times the allowable

material yield stress. The licensee determined

that the root cause of the deformation

was an inadequate

design thickness

specification.

Discussion:

An orifice plate is commonly used as a primary flow element, and produces a differential

pressure from which a flow rate can be determined., Orifice plates have a handle on which pertinent

data is permanently

marked, such as orifice diameter, flange size, pressure rating, and, as appropriate, the word "In-let." The two most common types of orifice plates are squared edge and beveled edge. On a beveled edge orifice plate that is properly installed, the word Inlet" faces the inlet direction

and the beveled edge faces the outlet direc-tion. A square edged orifice plate is not dependent

upon orientation

to perform its function.

However, Installation

procedures

for both types of orifice plates should be consistent.

A beveled orifice plate that is installed backwards

would provide a lower differential

pressure across the flow element, resulting

in a flow rate measurement

that is lower than the actual flow rate.

IN 90-65 October 5, 1990 Orifice plates are also used as flow restrictors, to provide a specific hydraulic

resistance

in a piping system to limit flow rate. A failure of the orifice plate could cause excessive

recirculation

or bypass flow, which may decrease the flow being delivered

to the main flow path during an accident.The failure of the orifice plate could also reduce the hydraulic

resistance

in the system, increasing

the total pump flow rate and the probability

of centrif-ugal pump runout. Runout could damage the internal components

of the pump, lead to inadequate

net positive suction head, and overload the pump motor.Increased

flow rates in the orificed line could also lead to increased

pipe vibration

and erosion. In addition, permanently

deformed orifice plates could provide inaccurate

flow measurements.

This information

notice requires no specific action or written response.

If you have any questions

about the information

in this notice, please contact one of the technical

contacts listed below or the appropriate

NRR project manager.A Charles E. Rossi, Director Division of Operational

Events Assessment

Office of Nuclear Reactor Regulation

Technical

Contacts:

Scott Sparks, Region II (404) 331-4187 Andrew Kugler, NRR (301) 492-0834 Attachment:

List of Recently Issued NRC Information

Notices

• I I Attachment

1 IN 90-51 October 5, 1990 Page I of I LIST OF RECENTLY ISSUED NRC INFORMATION

NOTICES Intormation

cat. or Notice no. SubJect Issuance Issued to 90-64 Potential

for Comma-Mode

10/4/90 All holders of Failure of High Pressure OLs or CPs for Safaty Injectlon

Pumps or pressurized-water

Release of Reactor Coolant reactors.Outside Containment

During A Loss-Of-Coolant

Accident 90-43 Management

Attention

to the 10/3/90 All fuel cycle Establishment

and Main. licensees

possess-tenance of A Nuclear Ing more than Criticality

Safety Program crtrcal mss quantities

of special nuclear material.90-42 Requirements

for Import 9/25/90 All irradiated

and Distribution

of gemstone importers Neutron-Irradiated

Goes end distributors.

and all non-power licensees.

90-41 Potential

for Residual 9/20/90 All holders of Heat Removal Pump OLs or CPs for Pump Damage Caused By nuclear power Parallel Pump interaction

reactors.90-60 Availability

of Failure 9/20/90 All holders of Data In the Government.

OLs or CPs for Industry Data Exchange nuclear power Program reactors.90-59 Errors In the Use of 9/17/90 All medical Radioactive

todine-131 licensees.

90-58 Improper Handling of 9/11/90 All NRC medical-Opttaft& Strontiua.9L

._ iceasees.Beta Radiation

Applicators

90-S7 Substandard, Refurbished

9/5/90 All holders of OLs Potter S Brumfield

Relays or CPs for nuclear Misrepresented

As Nw power reactors.OL

• Operating

License CP

• Construction

Permit UNITED STATES NUCLEAR REGULATORY

COMMISSION

WASHINGTON, D.C. 2055 OFFICIAL BUSINESS PENALTY FOR PRIVATE USE. $300 FIRST CLAS MAIL POSTAGE & FEES PAID USNAC: PERMIT@ No a9 IN 90-65 October 5, 1990 Orifice plates are also used as flow restrictors, to provide a specific hydraulic

resistance

in a piping system to limit flow rate. A failure of the orifice plate could cause excessive

recirculation

or bypass flow, which may decrease the flow being delivered

to the main flow path during an accident.The failure of the orifice plate could also reduce the hydraulic

resistance

in the system, increasing

the total pump flow rate and the probability

of centrif-ugal pump runout. Runout could damage the internal components

of the pump, lead to inadequate

net positive suction head, and overload the pump motor.Increased

flow rates in the orificed line could also lead to increased

pipe vibration

and erosion. In addition, permanently

deformed orifice plates could provide inaccurate

flow measurements.

This information

notice requires no specific action or written response.

If you have any questions

about the information

in this notice, please contact one of the technical

contacts listed below or the appropriate

NRR project manager., n- Charles E. Rossi, Director Division of Operational

Events Assessment

Office of Nuclear Reactor Regulation

Technical

Contacts:

Scott Sparks, Region II (404) 331-4187 Andrew Kugler, NRR (301) 492-0834 Attachment:

List of Recently Issued NRC Information

Notices Document Name: ORIFICE*SEE PREVIOUS CONCURRENCES

• • SEE PREVIOUS FAX CONCURRENCE

• OGCB:DOEA:NRR

• • RII *RPB:ADM C/OGCB:DOEA:NRR

D/DOEALI _-AJKugler SSparks TechEd CHBerlinger

CERossir 09/06/90 09/10/90 09/12/90 09/26/90 W/, /90

IN 90-XX September

xx, 1990 Orifice plates are also used as flow restrictions, which provide a specific hydraulic

resistance

in a piping system to limit the flow rate. A failure of the orifice plate could cause excessive

recirculation

or bypass flow, which may decrease the flow being delivered

to the main flow path during an accident.The failure of the orifice plate could also reduce the hydraulic

resistance

in the system, increasing

the total pump flow rate and the probability

of centrif-ugal pump runout. Runout could damage the internal components

of the pump, lead to inadequate

net positive suction head, and overload the pump motor.Increased

flow rates in the orificed line could also lead to increased

pipe vibration

and erosion. In addition, permanently

deformed orifice plates could provide inaccurate

flow measurements.

This information

notice requires no specific action or written response.

If you have any questions

about the information

in this notice, please contact one of the technical

contacts listed below or the appropriate

NRR project manager.Charles E. Rossi, Director Division of Operational

Events Assessment

Office of Nuclear Reactor Regulation

Technical

Contacts: Scott Sparks, Region II (404) 331-4187 Andrew Kugler, NRR (301) 492-0834 Attachment:

List of Recently Issued NRC Information

Notices Document Name: ORIFICE*SEE PREVIOUS CONCURRENCES

• • SEE PREVIOUS FAX CONCURRENCE

• OGCB:DOEA:NRR

AJKugler 09/06/90**RII SSparks 09/10/90*RPB:ADM TechEd 09/12/90 CB:DOEA:NRR

CHBerlinger

094 /90 D/DOEA:NR?,, CERoss I 09/ /90

IN 90-XX September

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 one of the technical

contacts listed below or the appropriate

NRR project manager.Charles E. Rossi, Director Division of Operational

Events Assessment

Office of Nuclear Reactor Regulation

Technical

Contacts: Scott Sparks, Region II (404) 331-4187 Andrew Kugler, NRR (301) 492-0834 Attachment:

List of Recently Issued NRC Information

Notices Document Name: ORIF OGCB:DOEANRR

AKugler 4t 09/06/90 RII #SSparks 09/ /90 RPB:ADM TechEd ,*09/ /90 C/OGCB:DOEA:NRR

CHBerlinger

09/ /90 D/DOEA:NRR

CERossi 09/ /90* sm A-TAcutc F&X)c ComcuARE.E4C

1. • Sm A1C(ED M iCgAeENJ c

An t w a = -T -!.Z ' d "IU101.0 ,_i izC 1 06/0 T/60 V,_=z=,=, .0 6 Ntl-JM-2 *93N WONA 4 0 IN t0-O Septber xx, Page 3 af 3 1990.4 This *' -= .VJ; o' req.l~ir '] n peciflt 1.;tdfln or written r nsponsS. If you Ce, F1t.tiCf1n

• outi4, V ;fcrmtsor

1i this nc1tsce. pse contact one of the technfcal (orltactb

VIst*d belcm or ttd !prOnr4j*t

NRR pro~ect .ioarger, Charqes C. RiOsOi Director Division Ic)l. iratl'onal

Events Asselssmot

Offif- ot Wu :lear Reactor egiltltfl lchm-Cal CWntG4%.S Scott (404)I+parkt. PAcgilo Il DJ1,31-413-1 Andreu Kugl9r nRR (301) 492.083$LiSt of Receltly issued NRC Ith(I i1 at 4n Notiels Attachfrlet:

OGCBfD0' -A;,dR.-'I 4/1 -09/06/90 Okif RI I Vi SSparks 09d/ 0/90 RP3~ ADM T ehEd 09/ /90 C/OGCB DO5A:NRR CH3erl inger o,/ /90 D/DOEA: NRP CERs9 9 09! /90

.90 Sg ?0 p 39 IN 90-XX September

xx, 1990 I This Information

notice requires no specific action or written response.

If you have any questions

about the information

in this notice, please contact one of the technical

contacts listed below or the appropriate

NRR project manager.Charles E. Rossi, Director Division of Operational

Events Assessment

Office of Nuclear Reactor Regulation

Technical

Contacts: Scott Sparks, Region II (404) 331-4187 Andrew Kugler, NRR (301) 492-0834 Attachment:

List of Recently Issued NRC Information

Notices Document Name: ORIF OGCB:DOEA:NRR

AKugler 09/ /90 RII SSparks 09/ /90 RPB:ADM TechEd MYWr-09/]i/0 C/OGCB:DOEA:NRR

CHBerlinger

09/ /90 D/DOEA:NRR

CERossi 09/ /90