Information Notice 1986-06, Failure of Lifting Rig Attachment, While Lifting Upper Guide Structure at St. Lucie Unit 1

Failure of Lifting Rig Attachment, While Lifting Upper Guide Structure at St. Lucie Unit 1

ML031220538
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, Skagit, Marble Hill
Issue date:	02/03/1986
From:	Jordan E L NRC/IE
To:
References
IN-86-006, NUDOCS 8601290056
Download: ML031220538 (7)

SSINS No.: 6835 IN 86-06 UNITED STATES NUCLEAR REGULATORY

COMMISSION

OFFICE OF INSPECTION

AND ENFORCEMENT

WASHINGTON, D.C. 20555 February 3, 1986 IE INFORMATION

NOTICE NO. 86-06: FAILURE OF LIFTING RIG ATTACHMENT,WHILE

LIFTING THE UPPER GUIDE STRUCTURE

AT ST. LUCIE UNIT 1

Addressees

All nuclear power facilities

holding an operating

license (OL) or a construction

permit (CP). .

Purpose

This notice is provided to advise licensees

of a potentially

significant

problem that occurred during the movement of a heavy load over the reactor core. It is expected that recipients

will review this information

for applicability

to their facilities

and consider actions, if appropriate, to preclude similar problems at their facilities.

However, the suggestions

contained

in this notice do not constitute

NRC requirements;

therefore, no specific action or written response is required.Description

of Circumstances:

On November 6, 1985, while lifting the upper guide structure

from the St.Lucie Unit 1 reactor vessel, licensee personnel

noticed the lifting rig tilt.The lift was immediately

stopped, with the lifting rig canted upward about 6 inches and the guide structure

canted downward about 6 inches at one of the three attachment

points. An attempt was promptly made to lower the'load back to its installed

position, but the load cells indicated

binding, so the attempt was terminated

after lowering the load a few inches. The 50-ton load was left suspended

about 8 feet above the reactor core.The licensee declared an Unusual Event. Core alteration

containment

integrity was enhanced by resuming full use of the airlocks.

Temporary

primary manway covers were installed

on bcth hot and cold legs to enhance the nozzle dams.Survey transits were set up and procedures

implemented

to monitor the rig and load for any shifts in their positions.

The licensee and the nuclear steam system supplier, Combustion

Engineering, designed and tested a supplementary

lifting rig to support the upper guide structure

from the upper portion of the normal rig, using a cable and J-hook system. On November 9 with the supplementary

rig installed, the load was jacked to a level orientation

and moved to its normal parking position in the refueling

pool.8601290056 IN 86-06 February 3, 1986 Damage caused during the incident included bending the lifting rig and one of the two guide pins that align the rig with the reactor vessel.Discussion:

The upper guide structure

is shown in Figure 1. It is supported

in the reactor vessel by it§..upper

flange. It is aligned by eight alignment

keys, four at the top and fourat the bottom. The structure

fits down inside the core support barrel, just'above

the fuel assemblies (see Figure 2). The fuel assembly alignment

plate is the bottom component

of the upper guide structure.

The lifting rig is attached to the upper guide structure

by three vertically

oriented bolts. These bolts are attached from above the water line by torque tools that run down the hollow columns of the rig (see Figure 3). Combustion

Engineering's

procedure

for attaching

the rig calls for checking for thread engagement

and torquing each bolt to 50 ft-lbs. The licensee's

procedure omitted the step concerning

the check for thread engagement.

Subsequent

inspection

of the bolt that had pulled loose indicated

that part of the last thread was stripped.

It is assumed that this bolt cross-threaded

or bound due to rig to guide structure

misalignment

during attachment

and reached the 50 ft-lb torque requirement

with only part of one thread engaged. During the lift, the few inches of unengaged

bolt shaft were pulled through the lifting rig until the bolt head rested on the rig's surface at the bottom of the column, resulting

in an imperceptible

tilt. The resulting

lateral load was initially

s6pported

by the guide pins. When the rig and guide structure

were lifted about 8 feet, where the guide bushings on the lifting rig reached the tapered portion of the guide pins, it is surmised that sufficient

lateral motion was permitted

to allow the thread of the improperly

engaged bolt to slip free. This caused the observed motion and tilt.After the guide structure

was supported

by the supplemental

lifting rig and leveled, it was moved to its normal parking position in the refueling

pool.The short attachment

bolts and torque tools were then replaced with full-length

bolts.- The long bolts are designed with heads that rest on surfaces at the top of the three hollow columns of the lifting rig. This has the advantage

of making anyflmck of full thread engagement

more apparent to the personnel attaching

the rig. The guide structure

was subsequently

returned to its installed

position using the long attachment

bolts.The licensee has not yet decided whether to permanently

modify the attachment

bolts. The licensee plans to review all reactor-related

lifts for adequacy of the procedures

to ensure proper lift rig attachment, including

provisions

for measuring

thread engagement.

The potential

consequences

of dropping heavy loads into the open reactor vessel were addressed

by Unresolved

Safety Issue (USI) A-36, "Control of Heavy Loads Near Spent Fuel." The concern for a UGS drop is that fuel assemblies

might be sufficiently

damaged to release the radioactive

gases and iodines held within the fuel-clad

gap. Under the reduced containment

integrity

requirements

for the refueling

mode, damage to several fuel assemblies

might cause the radiation dose limits of 10 CFR 100 to be exceeded.

IN 86-06 February 3, 1986 Plant specific calculations

were not made for a UGS drop at St. Lucie because the NRC determined

that further calculations

were not required after reviewing initial calculations

previously

submitted

by other reactor facilities

in response to Phase II of USI A-36. Some indication

of the consequences

of a UGS drop at St. Lucie can be gained from calculations

performed

by Combustion

Engineering

for a reactor vessel head drop at Waterford

3. The head drop calculations

assumed the reactor vessel head was sufficiently

tilted at impact to directly strike the UGS with the UGS at rest in its normal installed

posi-tion. The calculated

response velocity of the Waterford

UGS was 28 feet per second, and the resulting

vertical stresses imposed on the fuel were not sufficient

to rupture the cladding.If the St. Lucie UGS had dropped from an 8 foot elevation, its striking velocity would have been substantially

less than the UGS response velocity calculated

for the Waterford

head drop. However, the potential

for misalignment

of the recesses in the bottom of the UGS (i.e., the fuel assembly alignment

plate)with the fuel assembly upper end fitting posts was not addressed

by the Waterford scenario.

If substantial

misalignment

occurred, the fuel could be subjected

to additional

axial loading. Significant

misalignment

could not occur without substantial

impact damage to the eight keys and keyways, which would also result in a reduced striking velocity of the UGS as it reached the fuel. On this basis, significant

radioactive

gas release is considered

to be unlikely, although it has not been shown to be impossible.

No specific action or written response is required by this notice. If you have any questions

regarding

this matter, please contact the Regional Administrator

of the appropriate

NRC regional office or this office.ar Jordan, Director Divisio of Emergency

Preparedness

and gineering

Response Office of Inspection

and Enforcement

Technical

Contacts:

S. M. Long, IE (301) 492-7159 D. E. Sells, NRR (301) 492-9735 Attachments:

1. Figure 1, Upper Guide Structure

Assembly 2. Figure 2, Reactor Internals

Assembly 3 Figure 3, Upper Guide Structure

Lifting Rig 4. List of Recently Issued IE Information

Notices

Attachment

1 IN 86-06 February 3, 1986 EXPANSION COMPENSATING

RING CEA SHROUD GRID ASSEMBLY.CEA SHROUDS FUEL ASSEMBLY ALIGNMENT

PLATE Figure 1: Upper Guide Structure

Assembly (St. Lucie Unit 1 FSAR-figure

4.2-10)

UPPER GUIDE-STRUCTURE

SUPPORT PLATE Attachment

2 IN 86-06 February 3, 1986 CEA SHROUD IN-CORE-INSTRUMENTATION

GUIDE TUBE OUTLET CORE' SUPPORT BARREL FUEL ALIGNMENT PINS CORE-SUPPORT ASSEMBLY Am. 3-7/85 Figure 2: Reactor Internals

Assembly (St. Lucie Unit 1 FSAR figure 4.2-7)

At ta chment3 IN 86-06 February 3, 1986 LIFT POINT FOR CRANE HOOK CLEVIS ASSEMBLY WORKING PLATFORM I NSTRUMENT STALK OPENING-COLUMN GUIDE BUSHING FOR R.V. GUIDE PIN a PLACES)-00 LIFT BOLT Fi gure 3: Upper Guide Structure

Lifting Rig (St. Lucie Unit 1 FSAR figure 9.1-8)

Attachment

4 IN 86-06 February 3, 1986 LIST OF RECENTLY ISSUED IE INFORMATION

NOTICES T nfn,'mnfi

n Notice No. Subject Date oT Issue T-Issud tn Issu---- --ud t 86-05 86-04 86-03 86-02 86-01 85-101 85-100 85-99 85-98 Main Steam Safety Valve Test 1/31/86 Failures And Ring Setting Adjustments

Transient

Due To Loss Of 1/31/86 Power To Integrated

Control System At A Pressurized

Water Reactor Designed By Babcock& Wilcox Potential

Deficiencies

In 1/14/86 Environmental

Qualification

Of Limitorque

Motor Valve Operator Wiring Failure Of Valve Operator 1/6/86 Motor During Environmental

Qualification

Testing Failure Of Main Feedwater

1/6/86 Check Valve Causes Loss Of Feedwater

System Integrity And Water-Hammer

Damage Applicability

of 10 CFR 21 12/31/85 To Consulting

Firms Providing Training Rosemount

Differential

12/31/85 Pressure Transmitter

Zero Point Shift Cracking In Boiling-Water-

12/31/85 Reactor Mark I And Mark II Containments

Caused By Failure Of The Inerting System All PWR facilities

holding an OL or CP All power reactor facilities

holding an OL or CP All power reactor facilities

holding an OL or CP All power reactor facilities

holding an OL or CP All power reactor facilities

holding an OL or CP All power reactor facilities

holding an OL or CP All power reactor facilities

holding an OL or CP All BWR facilities

having a Mark I or Mark II containment

All Westinghouse

designed PWR facilities

holding an OL or CP Missing Jumpers From Westing- 12/26/85 house Reactor Protection

System Cards For The Over-Power Delta Temperature

Trip Function OL = Operating

License CP = Construction

Permit