ML20039B814

Deficiency Rept Re Spent Fuel Cask Handling Crane.Crane Design Will Be Modified to Comply w/NUREG-0554 Requirements

ML20039B814
Person / Time
Site:	Washington Public Power Supply System
Issue date:	12/08/1981
From:	Mazur D WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:	Faul Kenberry R, Faulkenberry R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
10CFR-050.55E, 10CFR-50.55E, GO1-81-415, NUDOCS 8112230588
Download: ML20039B814 (5)

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DocketNos.5bI60/513

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Washington Public Power Supply Sy'stesh ~ _

.7 \_ N P.O. Box 968 3000 GeorgeWashingtonWay Richland, Washington 99352 (509)372-5000 ,(

December 8, 1961 -s GO1-81-415 ^'

Nuclear Regulatory Commission Region V ,

1450 Maria Lane s Suite 210 '

Walnut Creek, C611fornia 94596 -

Attention: Mr. R. H. Faulkenberry ' ~"

Chief, Reactor Construction - ,

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Projects Branch 7 , ,

Subject:

PROJECTS 1 AND 4 '

~ %s DOCKET NOS. 50-460 AND 50-513

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REPORTABLE CONDITION 10CFR50.55(e) N ~

SPENT FUEL CASK HANDLING CRANE ,- M cb s'

Reference:

1) Telecon TJ Houchins, Supply System to DF Kirsch, Region V

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Nuclear Regulatory Commission . +

N dated January 7,1981 Dgg 8JS 7o2 / 1. C '

2) G01-81-27, dated February 2, 1981, DW Mazur to RH Engelken, Director N

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3) G01-181-163, dated June 1, 1981, - O DW Mazur to RH Faulkenberry, Chief, Reactor Construction Inreference(1)theSupplySysteminformedyourofficeofareportab1E deficiency under 10CFR50.55(e) and references (2) and (3) were interim ' # '

reports on the subject condition.

Attachment "A" includes a restatement of the reportable condition and a brief description of our selected alternative for correcting the-deficiency. Included in Attactment "A" is a detailed outline of the actions the Project is taking to implement.the corrective action. '

With the exception of a completion date, which is dependent on the crane manufactures schedule, this completes our reporting ~ action for this item. At such time as we can establish a firm completion date we will so inform your office.

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' e R. H. Faulkenberry Cask Handling Crane Page Two If you have any questions or desire.further information, please advise.

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..h Very truly yours,

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D. W. > zur Program Director CRE:MER:lm Attachment cc: CR Bryant, Bonneville Power Administration /399 RT Johnson, Quality Assurance WNP-2/917Q V. Stello, Director of Inspection, NRC FDCC/899 x

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ATTACHMENT A WNP-1/4 DOCKET NOS 50-460 AND 50-513 REPORTABLE CONDITION 10CFR50.55(e)

SPENT FUEL CASK HANDLING SYSTEM INTERIM REPORT BACKGROUND As described in sections of the WNP-1/4' PSAR (1973), the structural design parameters for the General Services Building (GSB), spent fuel storage pool and spent fuel handling equipment, were based on a 150 ton spent fuel cask free falling from a maximum height of 30 feet, resulting in a missile type ~ impact load on the fuel pool floor slab.

The drop was hypothesized to occur as a result of a' single failure of the crane or a safe shutdown earthquake (SSE). The fuel pool floor slab was to be designed to withstand this type of loading without adversely affecting our ability to assure a safe shutdown of the plant. In the event of either a single failure or SSE,'the orignal design analysis concluded that the fuel pool floor slab could withstand the drop of a loaded cask without affecting the-safe operation of the plant.

DESCRIPTION OF DEFICIENCY It has been determined, as a result of design reviews conducted by

- UE8C Engineering, that more restrictive load limits must be placed

-on the GSB structure. Recent information has stown that the values for concrete ductility used in the original design, do not provide conservative results and therefore a lower value for ductility must be used. Based on the most recent design calculations performed by UE&C, it has been determined that the spent fuel pool storage slab could not withstand the impact loading of a 150 ton spent fuel cask falling from a height of 30 feet. The energy imparted by the cask falling from that height would probably result in structural collapse of the floor slab allowing the cask to fully penetrate the slab.

SAFETY IMPLICATIONS In event of either the cask fully penetrating or partially penetrating the floor, critical plant equipment would be affected. Partial penetration would cause severe spalling or chipping of concrete on the tension (underneath) side of the-floor, possibly resulting in destructive damage to the equipment below i.e., Containment Spray System, Decay Heat Removal System and Auxiliary Feedwater System. Full penetration of the cask would render any equipment in its path inoperable. Any damage to the

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equipment mentioned above has been deemed unacceptable and could adversely affect the ability-to assure a safe shutdown of the plant.

REPORTIBILITY It was determined that the condition, if left uncorrected, could have adversely affected the safety of operation of the plant upon failure of the spent fuel cask crane. This condition has been determined to be reportable, a

CORRECTIVE ACTION UE&C and the Supply System have reviewed the options available to them for alleviation of the design deficiency, namely strengthening the floor slab or providing redurdancy within the cask handling crane along with seismically qualifying it. The Project has opted to modify the existing crane to comply with the requirements of NUREG 554.

At the time it was decided to redesign the crane, it was also decided to reduce the maximum load carrying capacity of.the crane from 150 tons to 105 tons. It also must be noted that the fuel pool floor could not withstand the impact load of a 105 ton spent fuel cask free falling from a height of 30 feet. The reduction in capacity was made because it more adequately reflects the real life usage situation, and that providing for a seismically qualified crane with a 150 ton capacity was a severe case of over specification since the cask to be used at WNP-1/4 is in actually a 75 ton cask. In keeping with this plan of action, the Supply System is contracting with the original crane.manu-facturer (Harnischieger) to provide for the redesigning and rebuilding of the existing crane.

The scope of the contract (which is presently being reviewed by the vendor) establishes NUREG 554 as the controlling requirements document to be followed in all phases of design and modification of the crane.

More specifically, the contractor has been advised of the following operating constraints in order to establish.a baseline for his design:

1. The reliance for the safe handling of a Maximum Critical Load (MCL) of 105 tons is placed upon the crane system itself.

2. In accordance with this established MCL, the crane is to meet single failure proof criteria as directly established by NUREG 554.

3. The crane system is to be seismically qualified with this same 105 ton lifted load in accordance with NUREG 554 and Regulatory Position 2 of Regulatory Guide 1.29.

4. The vendor shall develop a testing program which shall include the following:

a. An initial proof gest of the crane system at minimum operating temperature of 55 F and 125% of MCL, followed by non-destructive examination of welds whose failure could result in the drop of a critical load. This non-destructive examination will be repeated at maximum intervals of four years. Supply. System Engineering will coordinate with Plant Operations to assure inclusion of the nondestructive examination requirements into the plant maintenance program.

5. In order. to comply with NUREG 554,the vendors redesign shall include but not be limited to the following:

1) Fabrication of-a new trolley-frame

2) New drums with redundant grooving

3) Redundant bottom block, upper block and equalizer

4) Redundant. hook (hook within a hook)

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The Supply System shall develop operational guidelines in accordance with NUREG 554.

The responsibility for the review and approval of the crane design modifications has been assigned to United-Engineers and Constructors, Inc.

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