ML19320D588

Forwards Questions Re Failure of Holddown Spring on Fuel Assembly.Response Should Be Submitted in Time for NRC to Include Discussion in Safety Evaluation for Reload

ML19320D588
Person / Time
Site:	Davis Besse
Issue date:	07/01/1980
From:	Novak T Office of Nuclear Reactor Regulation
To:	Crouse R TOLEDO EDISON CO.
References
NUDOCS 8007210573
Download: ML19320D588 (3)

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Mr. Richard P. Creuse Ringram r v.

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Vice President, Nuclear CELD Toledo Edisen Cospany AE00 Edison Plaza 300 Madison Avenue Toledo, Ohio 43652

Dear Mr. Crouse:

On May 13, 1980 you infermed us of the failure of a holddown spring en a fuel assembly which was observed during underwater inspections of the fuel in the reactor vessel during the current refueling outage. Based upon your subsequent inspections, additional holddown spring failures were identified and reported.

On June 10, 1980, a :aeeting was held in Bethesda with.1 enters of your staff and S&W to discuss the status of the inspections. The presentation of the meeting was organized to address a set of questions that we had iWormally transmitted to ycur staff prior to the meeting. Although these nestions were addressed on June 10, we weuld like to formily decurnent your responses.

It is requested that you provide responses to the enclosed questionr in time for us to include an evaluation of this issue in the Safety Evaluati-.1 Report for ycur reload.

Sincerely,

..;;r.s! si p ad by

?.us:t H. Rcid Thomas M. Novak, Assistant Director for Operating Reactors Division of Ltcensing

Enclosure:

Holddown Spring Questicns cc w/ enclosure:

See next page l

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• July 1, 1980 Docket No. 50-346 Mr. Richard P. Crouse Vice President, Nuclear Toledo Edison Company Edison Plaza 300 Madison Avenue Toledo, Ohio 43652

Dear Mr. Crouse:

On May 13,1980 you inforno us of the failure of a holddown spring on a fuel assembly which was observed during underwater inspections of the fuel in the reactor vessel during the current refueling outage.

Based upon your subsequent inspections, additional holddown spring f ailures were identified and reported.

On June 10, 1980, a meeting was held in Bethesda with members of your staff and B&W to discuss the status of the inspections. The presentation of the meeting was organized to address a set c~ questions that we had informally transmitted to your staff prior to the meeting. Although these questions were addressed on June 10, we would like to formally & Jment your responses.

It is requested that you provide responses to the er,sosed questions in time for us to include an evaluation of this issue in the Safety Evaluation Report for your reload.

Sincerely, s,

bI JI'.,ll*

Thomas M. Novak, Assistant Director for Operating Reactors Division of Licensing

Enclosure:

Holddown Spring Questions cc w/ enclosure:

See next page 4

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Toledo Edison Company ccw/ enclosure (s):

U. S. Nuclear Regulatory rasunission Mr. Donald H. Hauser. Esq.

kesident Inspector s.0ffice The Cleveland Electric 5503 N. State Route 2 Illuminating Cogany Oak Harbcr Ohio 43449 P. O. Box 5000 Cleveland, Ohio 44101 Director. Technical Assessment Division Gerald Charnoff Esq.

Office of Radiation Programs Shaw, 'ittman, Potts U.

v ronmental Protection Agency 18 MS

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Crystal Mall #2 Washington, D.C.

20036 Arlington, Virginia 20460 U. S. Environmental Protection Agency u

r, en y, nry and Hodge Federal Activities Branch 300 Madison Avenue Toledo, Ohio 43604 Region V Office ATTN:

EIS COORDINATOR Mr. Robert B. Scrsum 230 South Dearborn Street Babcock & Wilcox Chicago, Illinois 60604 Nuclear Power Generation Division Suite 420, 7735 Old Georgetown Road Bethesda, Maryla'id 20014 Ohio Department of Health ATTN: Director of Health Ida Rupp Public Library 310 Madison Street 450 East Town Street Columbus Ohio 43216 Port Clinton,0hio 43452 President, Board of County Comissioners of Ottawa County Port Clinton, Ohio 43452 Attorney General Department of Attorney General 30 East Broad Street Columbus, Ohio 43215 Harold Kahn, Staff Scientist Power Siting Comission 361 East Broad Street Columbus, Ohio 43216

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Mr. Rick Jagger Industrial Comission State of Ohio 2323 West 5th Avenue Columbus, Ohio 43216 Mr. Ted h ers Licensing Engineer Toledo Edison Company Edison Plaza 300 Madison Avenue Toledo, Ohio 43652

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Enclosuro HOLD-DOWN SPRING QUESTIONS TO L CENSEES 1

(If the reactor is down for refueling and the reactor vessel head is off) Examine all fuel assembly holddown springs in the core and in the s)ent fuel pool and report the number and extent ~of damage on the springs and affected assembly ccmponents, or (Alt.)- (If the reactor is operating.) Review video tapes of the core from the.last refueling and examine all assemblies in the spent fuel pools.

Report the number and extent of damage on the springs and affected assedly components.

2.

Provide a discussion of the safety significance of operating with one or more broken springs in the core. Your discussion should include, but not necessarily be limited to the following:

Assume the holddown spring is broken, provide an estimate of the(Provide a.

flow conditions under which the assedl1es would be levitated.

the value of the force required to lift the assembly, the flow conditions under which that force would be supplied, the number of coolant pumps that a

would be in operation under such conditions, and the schedule of reactor operations under which such conditions might have been achieved.) Contrarily, demonstrate the margin between the assembly weight and the calculated maximum applied lift-off force, if there is such margin.

b.

Have any loose assembly-parts (i.e., broken springs, pieces of cladding) been observed anywhere in the primary system? Describe your methods for loose part detection. Are there installed noise detectors capable of detection of broken springs, pieces of cladding, or vibrating assemblies?

c.

Have there been any excore or in-core reutron detector indications of levitatdd assemblies? Describe the expected reactivity effects that would result from lift-off or reseating of assemblies with broken hold-down springs. What efforts are being utilized to detect locse assemblies by either nuclear or mechanical monitoring devices?

d.

Have there been any observed indications of lateral repositioning of loose assemblies?. Describe the methods used to detect lateral assembly motion.

Describe the degree of lateral repositioning that is physically (dimensionally) possible after lift-off. What are the postulated worst-case effects of a laterally displaced assembly?

e.

(1) Describe the degree of " worst-case" mechanical damage that would be expected as a result of movement of a " loose" assembly (one with a broken spring) against adjacent assemblies, core baffle, or other core components.

'(i_i) Discuss the results of flow tests or other experiments that have provided measurements of axial or lateral vibratory motion of an assembly after lift-off or that would othenvise support the response to Q 2.'e(i).

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