ML20045D579
| ML20045D579 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 06/21/1993 |
| From: | Fenech R TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9306290167 | |
| Download: ML20045D579 (8) | |
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Tennessee Valley Authonty, Post Office Box 2000, Soddyha sy. Tennessee 37379 2000 Robert A. Fenech -
Vee President, Sequoyah Nuclear Plant June 21, 1993
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U.S. Nuclear Regulatory Commission l
ATIN:. Document Control Desk Washington, D.C. 20555 Gentlemen:
In the Matter of.'
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- Docket N'. L 50--327 o
Tennessee Valley Authority
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SEQUOYAH NUCLEAR PLANT (SQN):.. UNIT 1 DISCRETIONARY-ENFORCEMENT FOR-TECHNICAL SPECIFICATION-(TS) 3.9.6, " MANIPULATOR CRANE" This letter serves to document TVA's request for~a discretionary-enforcement for Unit 1 TS 3.9.6 to allow removal.of a' fuel assembly.
During the core reload for SQN Unit 1 Cycle 7 Fuel Assembly'H64 tipped' 1
from its designed core location, G-7, and rested against the: baffle.
TVA's recovery plan options.will not allow strict compliance.with TS 3.9.6.-
Specifically, TS.3.9.6 requires.the movement of fuel assemblies within the reactor. pressure vessel by1a manipulator crane that has minimum.capacityLof 2750-pounds.and an overload cutoff limit less-than'or equal to 2700 pounds. Compensatory actions.have been taken as'
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described in the enclosure that'has been approved by'the Plant Operations Review Committee and provides the basis for the discretionary enforcement.
In' order.to' allow the recovery of the fuel assembly,-. discretionary-enforcement was: requested ~on June 21,'1993..10n June 21,-1993,.atJ 1505"EST, Stewart Ebneter, Regional Administrator, verba11yLgranted.the discretionary enforcement to TS 3.9.6 notito exceed 24' hours,in duration-
-Erom'the' start of:the evolution. ~ This-approva11does not include use'of the polar crane for movement of the.FA.
Approval:for use of-.the polar.
crane will be. contingent; upon further discussion. with NRC.
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June 21, 1993 Please direct questions concerning this issue to J.'D.-Smith'at (615) 843-6672.
j Sincerely, i
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f Robert A. Fenech E
Enclosure L
cc (Enclosure):
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Mr. D. E. LaBarge, Project Manager'
(
U.S. Nuclear Regulatory. Commission l
One White Flint, North 11555'Rockv111e Pike l-Rockville, Maryland 20852-2739 NRC' Resident Inspector l
Sequoyah Nuclear Plant i
2600 Igou Ferry Road Soddy-Daisy, Tennessee 37379-3624 Regional Administrator U.S. Nuclear Regulatory Commission-Region II' 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323-2711 i
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i ENCLOSURE.
DISCRETIONARY ENFORCEMENT FOR TECHNICAL'SPECIFICATI0N'(TS) 3.9.6 L
FOR REMOVAL OF LEANING FUEL ASSEMBLY H64 l'
Background
During the core reload for SQN; Unit ~l Cycle 7 on' June.19,fl993,-Fuel:..
l' Assembly H64 tipped from its. designated.corefloc'ation,lG-7,{toltheL.
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- baffle..The assembly is leaning at:approximately 20 degrees off thej vertical angle. LNo fuel rods'of Fuel' Assembly H64.,are' expected to have D
been damaged l since no gas bubbles have been' observed Leoming from' the: fuel
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assembly and the radiation' monitors-inside containmentL are reading normal H
(there was no1 increase in-radiation as a. resultlof the tipped fuel:
assembly). The top nozzle, v)per parts' of; the guide. tubes,"and the lower ~
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nozzle.may haveLsustained some damage.- Visual. inspection.oflthese;
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components of the. fuel assembly'will be performed during:thelperformance' of Fuel Handling Instruction'(FHI)-3A',:" Recovery of Leaned Fuel Assembly (
i H64."- Figure 1 shows,the current core configuration. ' Figure;2 showsLthe side view of the leaning fuel assemblyz ith respect ~to'the~1ower-core w
plate and baf fle.-
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FHI-3A details'the recovery ~ evolution'from uprighting H64,Litsfeventual j
inspection and return..to.the spentLfuel poo11(SFP), land:postperformance activities of checking the manipulator; crane z-z axis tapelandclower-core h
plate.
The basic recovery. operation.is as follows:L
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- Use J-hooks with the. auxiliary hoist; on the manipulator. bridge to
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upright H64 and-move it to a baffle' location.
l Inspect the' fuel assembly for upper-norzle damage 1to:determinebif-any' obstructions; exist or if the upper. nozzle..is bent or unstable such that. the manipulator. crane could not bel used to lif t the ' fuel '
1 assembly for transport to the upender orLrod' cluster. control' assembly (RCCA) change fixture".:
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- Use the manipulator crane hoist or J-hook and polar crane'to move-
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Fuel Assembly H64 to the core side upender.-
- Inspect the; fuel assembly for damage-and bottom nozzle'"S" holes for L
obstruction.
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- Transfer the fuel assembly to SFP using1the transfer system.
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- Return the fuel assembly to the appropriate spent fuel pit? location.
L Contingency operations are in place to use.the.J-hooks:with the polar L
crane to remove the fuel assembly from the core and.let the' auxiliary
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. building-crane transport it through : the. fuel transfer : system in u the ' spent ?
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. fuel pit area.
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Figure 3 shows a schematic of the J-hook special lifting rig to be used.
Special requirements have been established to ensure that ten feet.of-water is always available for the shielding of the fuel assembly during lifting by marking on the lifting rig cables to identify the ten feet of water between the' fuel assembly _ and - the surface of the water. Also, an l
operator will be ready to stop vertical lifting of the fuel assembly by cutting power to the manipulator crane auxiliary hoist.. If the polar crane is used, cable lengths will facilitate ensuring ten-foot. depth such that it will.be physically impossible to exceed the lift limit. The two-adjacent fuel assemblies will be confirmed to be seated properly before the retrieval is performed.
in addition, as shown in Figure 3, a calibrated load cell will be l
utilized.
The load cell read-out will be monitored to ensure operations i
are discontinued should the pull-force exceed the nominal-weight of_the fuel assembly (approximately 1650 pounds) by 100 pounds.
The rigging used to upright the fuel assembly-with either the manipulator auxiliary bolst or the polar crane has been load tested to 2250 pounds.
l This is su' icient to lift a fuel assembly that weighs less'than 1650 i
pounds dry. The manipulator crane auxiliary. hoist and polar crane are i
capable of lifting a fuel assembly and the associated rigging. The use.
of the spent fuel pit bridge to transport the fuel assembly to a spent fuel pit storage location has been demonstrated during the-recent core offload, new fuel movements in the spent fuel pit,_and during core load-of 44 assemblies.
Thus, the lifting abilities of the rigging and hoist and/or crane are adequate.
The fuel assembly is to be uprighted, moved,.and lifted using J-hooks that are hooked onto the leaf springs of the fuel assembly. The fuel assembly will be lifted with either the manipulator crane, auxiliary hoist, the polar crane to the reactor cavity upender,-or the RCCA fixture.
The potential exists during the uprighting, moving. or lifting evolution to drop the fuel assembly, possibly causing fuel rod damage to and/or bumping-of the, surrounding fuel assemblies currently loaded into the core.
The procedure provides specific guidance on how the J-hook should be placed under the leaf springs.
In addition, the procedure contains detailed steps for the uprighting, moving, and lifting of the fuel assembly to prevent the bumping of the other fuel assemblies.' _The analysis in the Updated Final Safety Analysis Report (UFSAR) for a fuel-handling accident is bounding.
For Mode 6, the required shutdown margin is provided by the refueling boron concentration that is being maintained at or above the required 2000 parts per million.
There are' currently 44 fuel assemblies in the core.
The fuel assemblies are in their designated _ locations and Fuel Assembly H64 has an edge of its top nozzle leaning against the baffle wall and an edge of the bottom nozzle on the lower-core plate at core location, G-7.
The required shutdown reactivity has not changed as a
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result of this configuration since the leaning fuel assembly is not in-total contact with any other fuel assembly. The most limiting condition for shutdown reactivity control is bounding and that. condition is with-the. core fully loaded.
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TS Compliance The above description provides information in regard.to the condition that currently exists with respect to Fuel Assembly H64 and the evolutions planned for its recovery.. However, while the planned evolution and its contingencies.are consistent withiactions'taken by other licensees (Beaver Valley, Byron, and Indian. Point'3 Nuclear Plants), they are in conflict with TS 3.9.6..Specifically, TS 3.9.6' requires the movement of fuel assemblies within the. reactor pressure vessel by a manipulator crane'that has' minimum capacity of.2750 pounds and an overload cut-off limit'less than'or equal to 2700 pounds.
Compensatory actions are planned as discussed above, but will not allow strict-compliance with the TSs. Thus, a discretionary enforcement'was-requested from TS.3.9.6 beginning at approximately 0800 EST on. June 22,,
1993, not to exceed 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> in duration (Note that-the resident' inspectors will be informed of the actual time of entry into. the 24-hour time period.). The' above evolution is expected to be accomplished well within a 24-hour period; therefore, a permanent TS change is not requested. While the exact'cause as to why Fuel Assembly H64 was not' properly seated is not-known at this time, the condition is expected:to j
be nonrecurring.
Safety ConsequanARE As discussed above, no fuel rods of Fuel Assembly H64 are expected to have been damaged as no gas bubbles have been observed and no increase has been noted from the containment radiation monitors. ' Prompt action is necessary to ensure the stability of the fuel assembly and'further examination for any potential damage. With respect to_the recovery.
evolutions, the fuel handling accident described in the UFSAR remains bounding.
The use of the manipulator auxiliary hoist or polar crane was determined to have no safety significance because no actual component; functionality has been affected and the intent of the TS is being met.- Accordingly, the requested waiver cannot result in an increase in the probability or consequences of a previously evaluated accident,'cannot create the possibility of a new accident, and cannot reduce the margin of safety.
Therefore, the action does not involve an unreviewed environmental question because it does not increase any adverse. environmental impacts, change effluents or power levels, or result in unreviewed environmental matters.
NRC_Anprozed NRC approval of the discretionary enforcement was granted for use of the manipulator crane auxiliary hoist only, provided that the hoist has been tested to 2250 pounds within the past 100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br />. Approval to use the polar crane will be contingent upon further discussions with.NRC.
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