Information Notice 1986-58, Dropped Fuel Assembly

Dropped Fuel Assembly

ML031220720
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, 05000000, Zimmer, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant, Skagit, Marble Hill, Crane
Issue date:	07/11/1986
From:	Jordan E NRC/IE
To:
References
IN-86-058, NUDOCS 8607090433
Download: ML031220720 (4)

118 ORIGINAL

SSINS No.: 6835 IN 86-58

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF INSPECTION AND ENFORCEMENT

WASHINGTON, D.C.

20555

July 11, 1986

IE INFORMATION NOTICE NO. 86-58:

Addressees

All nuclear power reactor facilities holding an operating license or a con- struction permit.

Purpose

This information notice is to alert recipients to a potentially significant

problem pertaining to removal of nuclear fuel from the reactor core.

The NRC

expects that recipients will review this notice for applicability to their

facilities and consider actions, if appropriate, to preclude a similar problem

occurring at their facilities.

However, suggestions contained in this notice

do not constitute NRC requirements; therefore, no specific action or written

response is required.

Past Related Correspondence:

IE Information Notice 80-01, "Fuel Handling Events," January 4, 1980.

IE Information Notice 81-23, "Fuel Assembly Damaged Due to Improper Positioning

of Handling Equipment," August 4, 1981.

IE Information Notice 85-12, "Recent Fuel Handling Events," February 11, 1985.

IE Information Notice 86-06, "Failure of Lifting Rig Attachment While Lifting

the Upper Guide Structure at St. Lucie Unit 1," February 3, 1986.

Description of Circumstances

On February 26, 1986, at Haddam Neck, a spent fuel assembly was inadvertently

lifted from the core when the upper core support structure was removed from the

reactor vessel in preparation for refueling.

The assembly stuck to the struc- ture because of a bent fuel assembly locating pin.

These locating pins

protrude at the bottom of the upper core support structure and insert into the

fuel assembly upper nozzle alignment holes when the support structure is

properly in place.

One pin was bent toward the center of its fuel assembly, thus holding the assembly by pinching against the inner side of the alignment

hole.

With the support structure lifted above the reactor vessel, the bottom

of the attached assembly did not clear the top of the vessel.

As the structure

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IN 86-58 July 11, 1986 was moved laterally, the assembly impacted the core barrel and was knocked off.

The assembly dropped 2-4 feet onto the core.

The dropped assembly and the two

assemblies it impacted were damaged; however, no radiological release occurred

during this event.

All 3 assemblies and a symmetrically-burned assembly have

been withdrawn from use in the reactor.

The core barrel was superficially

scratched and a core baffle former plate was partially torn.

The licensee

determined that these latter items do not prevent continued use of these

structural components.

The licensee inspected fuel assemblies that occupied the same core position as

the dropped assembly in previous cycles. The chamfer of the guide pin align- ment holes of these assemblies was also deformed in the location of the bent

pin.

No such deformation was identified in other fuel assemblies.

This

indicated that the bent pin was the cause of the event and that the condition

may have existed since 1981, but previously did not result in enough interfer- ence to lift the fuel assembly when the upper core support structure was

removed.

The bent pin was repaired.

Discussion:

• A 240,000-lb capacity crane was used to lift the upper core support structure

weighing 57,000 lb.

The stuck fuel assembly weighed only 1200 lb, so the

procedural limit for the lift of 59,000 lb did not ensure that no fuel assembly

was attached to the structure.

Load cells of appropriate range and calibration

along with sufficiently restrictive limits may be helpful to ensure that loads

to be lifted are not encumbered. However in this application, the weight of

the fuel assembly is such a small fraction of the total load, that a load cell

may not be a reliable method of detecting an attached fuel assembly.

This event

illustrates the need during lifting for rigorous visual inspection as well as

sensitivity to instruments to ensure unencumbered lifts of heavy loads from the

reactor core.

Similar problems have been noted before.

As discussed in Information Notice

86-06, a stripped thread on a bolt attaching the lifting rig to the upper guide

structure at St. Lucie 1 may have caused an imperceptible tilt that later was

magnified to the observed tilt of the whole upper guide structure.

This bolt

was below the structure where the thread problem could not be readily observed.

As discussed in Information Notice 85-12, fuel assembly alignment pins did not

function properly in an event at Turkey Point 4. In that case, slight lateral

motion of the fuel handling bridge contributed to the misalignment.

Inadequate

control of the vertical position of the load was also highlighted in Informa- tion Notice 81-23.

IN 86-58 July 11, 1986 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.

Eaird Jordan, Director

Divisio of Emergency Preparedness

and Engineering Response

Vern Hodge, IE

(301)492-7275 Attachment:

Attachment 1

IN 86-58

July 11, 1986

LIST OF RECENTLY ISSUED

IE INFORMATION NOTICES

Information

Date of

Nottcd-No.

Subject

Issue

Issued to

86-57

86-56

86-55

86-54

86-53

86-52-

86-51

86-50

86-49

86-49

86-48-

Operating Problems With

Solenoid Operated Valves At

Nuclear Power Plants

Reliability Of Main Steam,,

Safety Valves

Delayed Access To Safety-

Related Areas And Equipment

During Plant Emergencies

Criminal Prosecution Of A

Former Radiation Safety

Officer Who Willfully

Directed An Unqualified

Individual To Perform

Radiography

Improper Use Of Heat Shrink- able Tubing

7/11/86

7/10/86

7/10/86

6/27/86

6/26/86

All power reactor

facilities holding

an OL or CP

All PWR facilities

holding an OL or CP

All power reactor

facilities holding

an OL or CP

All holders of by- product, source, or

special nuclear

material

All power reactor

facilities holding

an OL or CP

All power reactor

facilities holding

an OL or CP

All BWR 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

holding an OL or CP

Conductor Insulation Degrada- 6/26/86 tion On Foxboro Model E

Controllers

w

Excessive Pneumatic Leakage

6/18/86 In The Automatic Depressuriza- tion System

Inadequate Testing To Detect

Failures Of Safety-Related

Pneumatic Components Or

Systems

Age/Environment Induced

Electrical Cable Failues

Inadequate Testing Of Boron

Solution Concentration In The

Standby Liquid Control System

6/18/86

6/16/86

6/13/86 DL = Operating License

CP -Construction Permit