Information Notice 1987-56, Improper Hydraulic Control Unit Installation at BWR Plants

Improper Hydraulic Control Unit Installation at BWR Plants

ML031130489
Person / Time
Site:	Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, 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:	11/04/1987
From:	Rossi C Office of Nuclear Reactor Regulation
To:
References
IN-87-056, NUDOCS 8710290234
Download: ML031130489 (6)

. J SSINS-No.: 6835 IN 87-56 UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 November 4, 1987 NRC INFORMATION NOTICE NO. 87-56: IMPROPER HYDRAULIC CONTROL UNIT

INSTALLATION AT BWR PLANTS

Addressees

boiling water

All holders of operating licenses or construction permits for

reactors (BWRs).

Purpose

potential

This information notice is being provided to alert addressees to a (HCUs)

problem that could affect the ability of the hydraulic control units

to control the positioning of the control rods in the event of an earthquake.

system

In addition, the potential for damage to the control rod drive (CRD)a small- withdraw lines that exists under certain conditions could result in

recipients

break loss-of-coolant accident in the HCU area. It is expected thatand consider

will review this information for applicability to their facilities

con- actions, as appropriate, to avoid similar problems. However, suggestions therefore, tained in this information notice do not constitute NRC requirements;

no specific action or written response is required.

Background:

The CRD system controls the position of the control rods within the reactor

core either to change reactor core power or to rapidly shut down the reactorall

(scram). The HCU is a major component of the CRD system that incorporatesCRD

one

the hydraulic, electrical, and pneumatic equipment necessary to move includes

mechanism during normal or scram operations. This equipment, which

the accumulators, CRD insert lines, CRD withdraw lines, and scram valves, is

supported by the HCU frames.

Safe

If a sufficiently large number of HCU frame bolts are missing or loose, ofa the

Shutdown Earthquake (SSE) could result in damage affecting the ability

damage

CRD system to control the positioning of the control rods. In addition, to a CRD withdraw line could result in a small-break loss-of-coolant accident

in the area of the HCUs.

Description of Circumstances

on a

On May 4, 1986, at the Perry Nuclear Power Plant Unit 1, a hold-down bolt

CRD system HCU was found to be missing. Four other HCUs were observed with

hold-down bolt heads not in contact with the HCU frame. On May 15, further

investigation revealed that all of the HCUs had been installed with bolt torque

8 7 0 9 2-34

IN 87-56 November 4, 1987 values differing from the requirements of the seismic

mental Qualification Report. Also, the upper support testing in the Environ- junction modules (BJMs) was erroneously attached to for each of the 16 branch

an HCU frame. (A BJM is an

enclosure containing rod position sensor cable terminations

lating transformers for the Rod Control and Information and voltage regu- to one of a group of HCUs which it serves.) During System. It is mounted

attached to the HCUs in accordance with a General installation, the BJMs were

Electric

but the HCU seismic test configuration used for equipment Co. (GE) drawing, include a BJM. qualification did not

After the degraded condition of the HCUs at the Perry

issued letters to all BWR owners regarding Potentiallyplant was discovered, GE

Reportable Condition

(PRC) 86-08, "Improper Hydraulic Control Unit Installation."

informed the owners of the condition of the Perry HCU The letters

concluded that neither the missing or loose hold-down units. The letters

BJM attachment observed at the BWR/6 constituted a bolts nor the erroneous

faulted event at that plant, nor would they at any safety problem during a

remaining hold-down bolts were snug tight, they wouldother BWR because if the

the control rods. The GE letters did not address enable the HCU to scram

the possibility of damage to

a CR0 withdraw line that is attached to the HCU.

A-ruptured CRD line would

constitute a small-break loss-of-coolant accident.

During an inspection at Pilgrim Nuclear Power Station

on March 13, 1987 (in

f-o-GtEter

Lresponser

No. G-H Octo 2 l968Ydated

86, regading improper

HCU installation), Boston Edison Company (BECo) identified

bolts at the top and base of 31 of 145 HCU frames. loose or missing

washers were not installed with the base bolts, which Also, BECo found flat

installation drawing. The BECo engineering evaluation was contrary to the

tions concluded that design-basis operability of the of the as-found condi- lished for loading conditions postulated for the HCUs could not be estab- correct bolting to ensure the integrity of the HCUSSE. BECo installed the

structure.

Discussion:

Although the GE letter, based on the condition of the

provides some assurance that a safety problem does HCUs at the Perry plant, not

experience at the Pilgrim plant demonstrates that some necessarily exist, the

configurations might not meet seismic design criteria. improperly installed HCU

out that the responsibility for implementing adequate The GE letter pointed

rests with the utility and GE recommended that HCU HCU bolt hold-down torque

installations be checked to

ensure that:

1. The HCU mounting, whether with bolts or welding, is

seismic qualification test configuration. The utility consistent with the

the actual HCU seismic qualification torque value to may wish to use

tightness. ensure adequate

2. Where BJMs are incorporated, they are not attached

directly to the HCU

frame above the floor, except in cases where the BJM

in the equipment qualification results. has been considered

Attachoent

IN 87-56 Novneber 4, 1987 LIST Of RECENTLYISSUED

INFOIIATION INOTICES19t7

.aeC

_iyrmto

InTorwaf on Isanc Issued to

Notice No. Subt.t

'7-54 Portable Noisture/Sonsity 10/20/87 All MRelicensees

aus Recent Incidents authorized to

et Portable Oaugs Being possess portable

gauges.

Stolen or Lost

07-54 Emergency Respons Exercises 10/23/87 All holdersof OLs

or CPs for nuclear

power reactors.

87-53 Auxiliary Fedwater PUMP 10/20/87 All holdersof OLs

Trips Resulting from Lou or CPs for nuclear

Suction Pressure pouer reactors.

87-52 Insulation Ireakdownof 10/16/B7 All holders of OLs

Silicone Rubber-Insulated or CPs for nuclear

SInglo Conductor Cables power reactors.

Ouring 1r1ghPotential Testinr

C7-51 Failure of Low Pressure 10/1O367 All nuclearpower

Safety Injection PuMPOu reactor tacilities

to seal Probles holding anOL or CP.

67-SO Potential LOCAat High- IOD//87 All nuclear power

and Louw-Presure Interfacen reactor facilities

trom Fire Dame holding anOLor CP.

10/9/B7 All nuclear power

07-49 Deficiencies In Outside

Containment Flooding reactor facilities

Protection holdingen OL or CP.

87-48 Information Concerning the ID/I/B7 All nuclear power

Use of Anaerobic Adhesive/ reactor facilities

Sealants holdingen OL or CP.

87-47 Transportation of Radio- 10/5/87 All NR licensees

fraphy Devices authorized to menu- facture, distribute

and/oroperateradio- graphic xpoure

devicesand/Or

soure changers.

OL

• Operating License

CP

• Construction Permit

UNITED STATES FIRST CLASS MAIL

POSTAGE 6 FEES PAID

NUCLEAR REGULATORY COMMISSION USNRC

WASHINGTON, D.C. 20555 PERMIT NIo. 47 OFFICIAL BUSINESS

PENALTY FOR PRIVATE USE, *300

IN 87-56 November 4, 1987 Page 3 of-3 No specific action or written response is required

If you have any questions about this matter, please by this information notice.

contact listed below or the Regional Administrator contact the technical

office. of the appropriate regional

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Samuel MacKay, NRR

(301) 492-8394 Attachment: List of Recently Issued NRC Information Notices

IN 87-56 November 4, 1987 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

Samuel MacKay, NRR

(301) 492-8394 Attachment: List of Recently Issued NRC Information Notices

• SEE PREVIOUS CONCURRENCES

• OGCB:DOEA:NRR *PPMB:ARM *C/OGCB:DOEA:NRR

SDMacKay TechEd CHBerlinger

09/09/87 09/11/87 09/09/87

I I:

I -

IN 87-XX

September xx, 1987 No specific action or written response is required by this information notice.

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

Administrator of the appropriate regional office or this office.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Samuel MacKay, NRR

(301) 492-8394 Attachment: List of Recently Issued NRC Information Notices

C9 OGCB:DOEA:R PPMB:ARM C/OGCB:DOEA:NRR D/IWOEA:NRR

SDMacKay TechE ' CHBerlinger CERossi

o9/9 /87 091ij /$7 09/9 /87 09/ /87