Information Notice 1985-12, Recent Fuel Handling Events
| ML031180626 | |
| Person / Time | |
|---|---|
| Issue date: | 02/11/1985 |
| Revision: | 0 |
| From: | Jordan E L NRC/IE |
| To: | |
| References | |
| IN-85-012, NUDOCS 8502060449 | |
| Download: ML031180626 (6) | |
SSINS No.: 6835IN 85-12UNITED STATESNUCLEAR REGULATORY COMMISSIONOFFICE OF INSPECTION AND ENFORCEMENTWASHINGTON, D.C. 20555February 11, 1985IE INFORMATION NOTICE NO. 85-12: RECENT FUEL HANDLING EVENTS
Addressees
Purpose
- This information notice is provided as a notification of potentially signifi-cant problems pertaining to recent fuel handling events. This notice supple-ments Information Notice 80-01, which discussed similar events. It is expectedthat recipients will review the information for applicability to their facili-ties and consider actions, if appropriate, to preclude similar problems fromoccurring at their facilities. However, suggestions contained in this informa-tion notice do not constitute NRC requirements; therefore, no specific actionor written response is required.
Description of Circumstances
- Two events have occurred recently at nuclear power plants in which fuel wasdropped because of failures or deficiencies in hoist equipment. More detailsare provided in Attachment 1.(1) At Hatch I on October 6, 1984, a spent fuel bundle was dropped into itsstorage cell because of a possible inadvertent actuation of the fuelgrapple hook position switch. The switch cover was missing.(2) At Millstone 2 on November 8, 1984, a fuel pin dropped in the spent fuelpool during fuel assembly reconstitution because the gripping colletfingers slipped.Several additional events have occurred that are noteworthy because theyinvolve deficiencies or maloperation of fuel handling equipment or procedures.These are briefly summarized below; more detailed information is given inAttachment 1.(1) At Monticello on November 29, 1984, a spent fuel bundle handle was deformedduring transportation because of inadequate cask loading procedures.(2) At Palisades on April 4, 1984, a new fuel bundle was stuck in the refuelingmachine because of inadequate spreader bar air supply pressure.85020 41~~metice5-n IN 85-12February 11, 1985 (3) At Turkey Point 4 on April 5, 1983, a spent fuel assembly dropped backinto its storage cell when the hoist limit switches failed to preventupward movement of the assembly. This event also involved a proceduralinadequacy concerning these limit switches.(4) A second event at Turkey Point 4 on April 17, 1983, resulted in animproperly loaded (leaning) fuel assembly.(5) At Cook 1 on June 19, 1981, a fuel assembly was damaged in a collisionwith a shield wall because an entangled air hose had tripped a limitswitch.(6) Also at Cook 1 on August 4, 1982, a fuel assembly was cocked and lodgedin the manipulator bridge mast because the fuel handling procedures werenot properly followed.Discussion:This information notice briefly describes several events involving failures ordeficiencies in fuel handling equipment or procedures. In addition, InformationNotice 80-01 discusses two similar events at Pilgrim. In one, a spent fuelassembly was inadvertently raised high enough in the fuel pool to activate arearadiation alarms because the lifting hook was caught between the lifting bailand the assembly channel. In the other, a new fuel assembly dropped onto thetop of the storage fuel racks when the auxiliary hook latching device failed tohold the lifting bail when the assembly struck the top edge of the racks. Theradiological consequences of these events were minimal. Nevertheless, theevents are considered significant, in that they could have compromised plantsafety and could have been prevented. Licensees may wish to review theirprocedures in view of these events.No specific action or written response is required by this information notice.If you have any questions about this matter, please contact the RegionalAdministrator of the appropriate NRC regional office or this office.ward L. Jordan, D rector2ubdvision of Emerge cy Preparednessand Engineering esponseOffice of Inspection and Enforcement
Technical Contact:
C. V. Hodge, IE(301) 492-7275
Attachments:
1. Description of Recent Fuel Handling Events2. List of Recently Issued IE Information Notices Attachment 1IN 85-12February 12, 1985 Description of Recent Fuel Handling EventsHatch 1This event involved a possible inadvertent actuation of the fuel grapple hookposition switch. On October 6, 1984, with core unloading in progress, a spentfuel bundle was inadvertently dropped into its storage rack cell (a distance ofabout 12 feet), slightly deforming and scratching the bundle and rack. Beforethe event, no trouble had been experienced in grappling bundles. When thebridge operator lowered the affected bundle and detected contact of the bundlewith the rack, he stopped to align the bundle with its storage cell; then thebundle dropped. The licensee declared an unusual event and terminated it onconfirming that no fission gases had been released.Grapple tests and operator interviews indicated that the operator actionsrequired to position or rotate the fuel bundle could have resulted in inadver-tently operating the fuel grapple hook position actuation switch. GeneralElectric Service Information Letter (SIL) No. 298, dated August 1979, describesthe potential for inadvertent switch operation in conjunction with a slackgrapple hoist cable before the operator has verified that the fuel bundle isproperly seated. General Electric recommends that the owners of BWRs 1 through4 install a commercially available snap cover over the switch. The licenseehad installed the switch covers on the refueling platforms of Units 1 and 2;however, between 1979 and the present, the covers had been removed. Thelicensee originally used an epoxy-type adhesive to secure the covers, but nowhas bolted them into place.Millstone 2This event involved mechanical slipping of the fuel holding mechanism. OnNovember 8, 1984, during fuel assembly reconstitution in the spent fuel pool, asingle spent fuel pin was dropped during eddy current testing for claddingdefects. The pin was gripped by collet fingers inside a lono cylindricalprobe. Evidently these fingers slipped, possibly because of a weld repair atthe top of the pin. The fingers were adjusted to provide a more positive arip.Although this pin was retrieved, inspected, and showed no defects, it wasreplaced in its position in the fuel assembly by a stainless steel spacer. Thelicensee instituted an additional check for proper gripping of each fuel pinand completed the fuel assembly reconstitution.MonticelloThis event illustrates the need for an explicit checkpoint in the fuel caskloading procedure. On November 29, 1984, the handle on a spent fuel bundle wasfound deformed when it was off-loaded from a transportation cask to a storagerack at the GE Morris spent fuel storage facility. The bundle had not beenseated properly in the cask because horizontal tabs at the top of the bundlehad not been aligned properly with the cask, preventing the bundle from beingfullv inserted. No radiological effects were caused, but the event is signifi-cant because the fuel loading procedures were not carefully followe Attachment 1IN 85-12February 12, 1985 Surveillance was conducted for this loading of the cask, but there was not anexplicit check for proper seating of the bundles before the cask cover wasbolted in place. The licensee's corrective action is to institute such anexplicit check in the fuel loading procedures.PalisadesThis event involved inoperability of the fuel hoist mechanism. On April 4,1984, while reloading the core, a new fuel bundle stuck in the refuelingmachine. A combination of low spreader bar air supply pressure (40 psi vsnormal 50 psi) and air leakage from the spreader bar retraction hose fittingresulted in the spreader bar extending downward one inch below the hoistbottom. An interlock for the extended spreader bar prevented movement of thebridge trolley. After evaluating the situation, the licensee increased the airsupply pressure and inserted the bundle into the core. The licensee thencompleted core reload without further problem.Turkey Point 4This event involved a malfunction of the limit switches on the spent fuel pithoist and disclosed a procedural inadequacy. On April 5, 1983, during refuel-ing after a six month outage for steam generator repair, partially burned fuelassembly X-13-was being-lifted from its storage rack. The limit switches-failed to stop the upward movement of X-13, resulting in parting of the hoist-ing cable and causing the assembly to drop back into its rack.The crane design provides two different limit switches to restrict uppermotion: a power circuit limit switch and a geared limit switch. About threeweeks before actual fuel movement, testing indicated the switches would work,but the investigation after the event revealed that a linkage in the powerlimit switch was unhooked, which disabled the trip feature, and the gearedlimit switch was out of adjustment. Had the licensee tested the upper limitswitch under no load at the beginning of each shift, as required by OSHAregulations [29 CFR 1910.179(n)(4)] or recommended by industry guidance (ANSIB30.2-1976, "Overhead and Gantry Cranes"), this event could have beenprevented.The procedural inadequacy was the incorrect designation of the limit switches.The spent fuel pit crane test procedure indicated that the power circuit switchbacked up the geared switch; the operating procedure for that crane incorrectlyindicated the opposite. The operating procedure also contradicted the prohibi-tion stated in both procedures against using the two. switches as normal stop-ping devices.A second event occurred shortly afterward in which improper placement of a fuelassembly into the core was not readily detected. Because of the X-13 drop, itwas necessary to reconfigure the core loading sequence. Because only thecentral area was to be reconfigured, the approved fuel loading sequence startedwith assemblies on the core perimeter and spiraled inward. This sequence onlyprovided one or two adjacent surfaces (fuel or baffle plate), instead of theusual four, to guide an assembly being inserte Attachment 1IN 85-12February 12, 1985 On April 17, 1983, a small maladjustment of the fuel handling bridge position(less than an inch deviation) coupled with a slight bow in twice-burned fuelassembly X-04 led to placing X-04 astride of one of the two locating pins inits intended core position. As a result, X-04 fell over so that it leaned at a35 degree angle against two other assemblies in the core. Vessel lighting wassuch that the leaning assembly was not noticed until four additional assemblieshad been loaded, about an hour after the presumed fall. No release of fissionproducts occurred.Cook 1During refueling operations on June 19, 1981, a fuel assembly was damaged bystriking a shield wall retaining lip located in the refueling cavity, approxi-mately six inches high and several feet west of the reactor vessel. The assem-bly was being transported toward the fuel transfer area by the manipulatorcrane, but a fouled interlock had apparently allowed the gripper "full up"indicating light to come on without the assembly being fully inside the grippertube. As a result of the collision, one fuel rod from the 15 x 15 assemblydropped to the cavity floor and lodged behind a ladder. Three other rodsappeared bent. The interlock did not operate correctly because an entangledair hose had tripped a limit switch.A year later, a similar event occurred. During refueling operations on August4, 1982, fuel movement was suspended when the refueling equipment was incor-rectly operated. This resulted in a fuel assembly becoming cocked and lodgedin the manipulator bridge mast. The upender device had not been raised to thevertical position before the fuel assembly was lowered. This caused theassembly to slide along the upender cable and give the bridge operator a lowload indication. Thinking the fuel assembly was rubbing in the transferassembly, the operator proceeded to lift the fuel assembly until it becamelodged and bent between the mast and the cable, giving a high load reading. Thelicensee then investigated what had happened and suspended fuel movement. Underan approved special procedure, the cable was slackened. The assembly returnedto its former shape except for minor deformation and marks on a few fuel rods.This event involved a violation of a technical specification requiring thatprocedures be followed. The crane operator had failed to immediately stop andevaluate the situation (according to procedure) when he observed an unexplainedload change while lowering a fuel assembly into the transfer container. Thecrane operator also failed to check whether this container was in a position toreceive fue Attachment 2IN 85-12February 11, 1985LIST OF RECENTLY ISSUEDIE INFORMATION NOTICESInformation Date ofNotice No. Subject Issue Issued to85-1185-1085-0985-0885-0785-0685-0585-0485-0385-02Licensee Programs For 2/11/85Inspection Of ElectricalRaceway And Cable InstallationPosttensioned Containment 2/6/85Tendon Anchor Head FailureIsolation Transfer Switches 1/31/85And Post-Fire ShutdownCapabilityIndustry Experience On 1/30/85Certain Materials Used InSafety-Related EquipmentContaminated Radiography 1/29/85Source ShipmentsContamination of Breathing 1/23/85Air SystemsPipe Whip Restraints 1/23/85Inadequate Management Of 1/17/85Security Response DrillsAll power reactorfacilities holdinga CPAll power reactorfacilities holdingan OL or CPAll power reactorfacilities holdingan OL or CPAll power reactorfacilities holdingan OL or CPAll NRC licenseesauthorized topossess industrialradiography sourcesAll power reactorfacilities holdingan OL or CPAll power reactorfacilities holdingan OL or CPAll power reactorfacilities holdingan OL or CP, & fuelfabrication & pro-cessing facilitiesAll pressurized waterpower reactorfacilities holding anOL or CPAll power reactorfacilities holdingan OL or CPSeparation Of Primary Reactor 1/15/85Coolant Pump Shaft AndImpellerImproper Installation AndTesting Of DifferentialPressure Transmitters1/15/85OL = Operating LicenseCP = Construction Permit