ML20212C315

Forwards Info Clarifying Heavy Loads Considerations for NRC Review of 860825 Proposed Spent Fuel Pool Expansion Tech Spec Change,Per NRC 870105 Request

ML20212C315
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	02/25/1987
From:	Capstick R VERMONT YANKEE NUCLEAR POWER CORP.
To:	Rooney V Office of Nuclear Reactor Regulation
References
FVY-87-23, NUDOCS 8703030757
Download: ML20212C315 (13)

Text

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VERMONT YANKEE NUCLEAR POWER CORPORATION RD 5. Box 169 Ferry Road, Brattleboro, VT 05301 70 ENGINEERING OFFICE g

g 1671 WORCESTER ROAD FRAMINGHAM, MASSACHUSETTS 01701

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e TEL(PHONE 617-872-6100 February 25, 1987 FVY 87-23 United States Nuclear Regulatory Commission Washington, DC 20555 Attention:

Office of Nuclear Reactor Regulation Mr. V. L. Rooney, Senior Project Manager BWR Project Directorate No. 2 Division of BWR Licensing

References:

(a) License No. DPR-28 (Docket No. 50-271)

(b) Letter, VYNPC to USNRC, FVY 86-34, " Proposed Technical Specification Change for Spent and New Fuel Storage,"

dated April 25, 1986 (c) Letter, USNRC to VYNPC, NVY 86-147, dated July 24, 1986 (d) Letter, VYNPC to USNRC, FVY 86-73, dated August 15, 1985 (e) Letter, VYNPC to USNRC, FVY 86-88, dated September 26, 1986 (f) Letter, VYNPC to USNRC, FVY 86-98, dated October 21, 1986 (g) Letter, USNRC to VYNPC, NVY 86-217, dated October 22, 1986 (h) Letter, VYNPC to USNRC, FVY 86-107, dated November 24, 1986 (1) Letter, USNRC to VYNPC, NVY 87-02, dated January 5, 1987

Subject:

Information Clarifying Heavy Loads Considerations - Proposed Change No. 133, Spent Fuel Pool Expansion

Dear Sir:

By letter, dated January 5, 1987 [ Reference (i)], you requested Vermont Yankee provide information clarifying heavy loads considerations, as discussed in the December 23, 1986 meeting at NRC headquarters, in order for you to complete your review of the proposed spent fuel pool expansion Technical Specification change submitted April 25, 1986 [ Reference (b)]. Accordingly, provides clarification for each item identified in your January 5, 1987 letter summarizing the meeting.

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87030 PDR P

United States Nuclear Regulatory Commission February 25, 1987 Attention:

Mr. V. L. Rooney Page 2 We trust that the enclosed is responsive to your request; however, should

. you have any questions or require further information regarding this matter,

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please contact this office.

Very truly yours, VERMONT YANKEE NLICLEAR POWER CORPORATION

/

R. W. Capstick Licensing Engineer RWC/bam Enclosure 1

ENCLOSURE 1 CLARIFICATION 1 Provide a description of the rack lifting' device, including dose estimates for use of device..

-RESPONSE There are three devices used to lift spent fuel racks in the area of the spent fuel pool:

1.

Reactor Building bridge crane.

2.

PAR spent fuel rack module lifting frame.

3.

NES fuel storage rack vertical handling tool.

As stated in Vermont Yankee's transmittal on November 24, 1986 (TVY 86-107),

'the Reactor Building bridge crane has been reviewed and found to meet the single failure-proof requirements of NUREG-0612, Section 5.1.1(6) in the staff's Technical Evaluation Report on control of heavy loads, transmitted by letter of June 27, 1984.

The PAR spent fuel rack module lifting frame was designed prior to the implementation of NUREG-0612 and currently does not provide for single failure-proof lifting. The current configuration of the existing lifting frame has two lifting arms and rack lift points which were designed to lift the racks with an acceptable safety factor. At this time, calculations are being reviewed which will serve as a basis for a modification to the existing lifting frame and racks to meet NUREG-0612 requirements for two totally separate load paths from the rack to the crane. The PAR lifting frame will be modified as necessary to provide safety factors of three against operational yield stress and five against operational ultimate stress, including a dynamic load factor per CHAA-70, as allowed per ANSI N14.6-1978.

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The PAR racks will be modified underwater by divers to install two additional

' lift-points. 'These. lift points will be used in conjunction with slings

- attached to the Reactor Building bridge crane to provide a totally redundant

- load path from that of the PAR lifting frame. This second lifting system will be designed to provide safety factors equal to those of.the modified lifting frame. Together, these modifications will ensure that any single. failure during rack removal will not result in uncontrolled tilting, rot'ation, swing.

.or dropping of the existing racks.

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At this time, Vermont Yankee and the diving contractor are still developing the tooling and procedures necessary to modify the PAR racks. Additionally, removal of miscellaneous irradiated hardware from the spent-fuel pool is still b

in progress. Until this work effort is completed, representative dose surveys cannot be taken and estimates cannot be developed. Vermont Yankee will supply

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dose estimates in addition to those given in the November 24, 1986, submittal I

when the above work is completed. Please note thac the PAR racks will not be l

removed from the pool until after the 1987 outage, and so, will not need modifications until the.t time.

It is our plan to perform testing of the 1.

tooling and procedures during the moving of PAR Rack Nos. 15 and 18 presently scheduled to take place in March 1987. This will allow for any required revisions to the procedures and tooling to be performed prior to the actual-I rack removal.

l-The present NES storage rack vertical handling tool has been qualified to meet the single failure-proof requirements of NUREG-0612 based on increased safety l

factors of six against operational yield stress and ten against operational ultimate stress, including a dynamic load factor per CMAA-70, as allowed per ANSI N14.6-1978.

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At the December 23, 1986 meeting at NRC headquarters, the staff raised l

concerns on the consequence on any single failure with respect to tilt, i

rotation, or dropping of the rack despite the above-stated design requirements.

Because these concerns would involve lengthy and detailed i

calculations of rack tilting and dropping, Vermont Yankee has initiated a redesign of the NES vertical lifting tool. The lifting device which will be I

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3 used to install the new racks will be designed to insure two totally separate

' load paths from the building crane to the lift points on the rack. This design will provide redundancy such that any single failure will not result in uncontrolled tilting, rotation, swing, or dropping of the spent fuel. rack.

Both the modified lifting device for use in removal of the existing racks and the redesigned NES vertical lifting device will be subjected to a 150 percent load test and subsequent inspections by the manufacturer as required for redundant lifting devices in ANSI N14.6-1978. All inspections and testing at 4

Vermont Yankee prior to use and at the required intervals will be as stated in our submittal of November 24, 1986.

Because of the changes to the lifting devices noted above, it is not possible to provide specific information and drawings on the devices at this time.

However, Vermont Yankee shall ensure that the vertical lifting devices used to install and remove spent fuel racks will meet the requirements of NUREG-0612 by providing redundancy such that a single failure, either in a lift point or 4

on the lifting device, will not result in uncontrolled tilting, rotation, swing, or dropping of the racks. These devices will also comply with Section 6 of ANSI N14.6-1978.

l Finally, in Vermont Yankee's response to Question 25 in our November 24, 1986 submittal, we expressed our intent to use the NES fuel storage rack handling tool - horizontal, NES fuel storage rack upender, and a supplemental crane on the 252' level of the Reactor Building to upend the NES racks. Eowever, the current plans are to upend the racks in the Turbine Building loading bay rather than the Reactor Building. Because there is no safety-related equipment below or in the vicinity of this area, the NES Rack Handling Tool - Horizontal and the NES Rack Upender will be designed to standard industry practice and are not required to be load-tested as previously l

stated. The supplemental crane will no longer be required.

i

's CLARIFICATION 2 Describe load paths including procedural constraints such as minimum lifting height, avoidance of open hatches, expeditious routing, and contingent laydown areas.

RESPONSE

Attached, please find a drawing depicting the load paths and laydown areas to be used for the fuel pool rerack. Also attached are revisions to Sketches 11 and 12 from the response to Question 28 in Vermont Yankee's submittal of November 24, 1986 (FVY 86-107), showing the load paths within the spent fuel pool. Please note that the load paths provide the most expeditious routing possible while trying to follow structural floor members and avoiding open hatches, lifts over irradiated fuel, and interferences which would require an increase in lift height. This is consistent with our existing policy on heavy loads as docketed in our correspondence of December 18, 1984, (W. P. Murphy to D. B. Vassallo).

In all actuality, maximum lifting height for both the PAR and the NES racks will be dictated by the size of the racks and the design of the vertical lifting fixture. However, for all lifts, the maximum lifting height will be procedurally controlled to 12 to 14 inches in order to avoid the interferences shown on the attached drawing. The Installation and Test Procedure will require the tag man to verify the height at the beginning of each lift and to maintain the height at less than or equal to the maximum during the duration of the lift.

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CLARIFICATION 3 Provide citations or references pertaining to previous licensing discussions supporting the approach to heavy load paths used at Vernont Yankee.

RESPONSE

The following is a list of docketed correspondence between Vermont Yankee Nuclear Power Corporation (VYNPC) and the Nuclear Regulatory Commission (NRC) on NUREG-0612 requirements and safe load paths:

(a) Letter, VYNPC to USNRC, FVY 81-134, dated September 11, 1981.

(b) Letter, VYNPC to USNRC, FVY 83-122, dated November 30, 1983.

(c) Letter, VYNPC to USNRC, FVY 84-51, dated May 21, 1984.

(d) Letter, USNRC to VYNPC, NVY 84-139, dated June 27, 1984.

(e) Letter, VYNPC to USNRC, FVY 84-148, dated December 18, 1984.

In the above correspondence, Vermont Yankee has repeatedly expressed our position that heavy loads are lifted and moved directly to their intended destinations, carefully and expeditiously in order to minimize handling time.

It is also stated that pick heights are kept within reasonable limits.

Additionally, correspondence (d), above, contains the NRC Safety Evaluation Report and their consultants' Technical Evaluation Report which concludes that, "... Development of safe load paths at the Vermont Yankee plant is consistent with Guideline 1."

As stated in Vermont Yankee's submittal of November 24, 1986, the issue of safe load paths for the installation and removal of the spent fuel racks will be controlled via the concepts accepted by the NRC for Phase I of NUREG-0612.

Additionally, load paths will be physically controlled as described in the response to Clarifica'.lon 4.

a, CLARIFICATION 4 Describe how the load paths will be marked (12 feet acceptable).

RESPONSE

Vermont Yankee will control the load paths as follows. First, stanchions and ropes will be used to mark the load path (s) and laydown areas to be used for each lift prior to the lift. Additionally, a copy of the drawings given in Clarification 2 will be used by the tag man directing the lift to assure that the load paths are being adhered to.

Copies of the drawings will also be placed in the cab of the Reactor Building bridge crane for reference purposes. Installation procedures shall ensure that any deviations from the established load paths must first be approved by the appropriate management personnel.

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CLARIFICATION 5 Determine consequence of any single failure with respect to tilt, rotation, or dropping, and state results of this determination.

RESPONSE

As discussed in the response to Clarification 1, Vermont Yankee is committed to redesigning the vertical lifting devices to be used in the removal of the existing racks and the installation of-the new racks-to provide two totally separate, redundant load paths. Therefore, based on Vermont Yankee's commitment to meet NUREG-0612 requirements for a single failure-proof vertical handling systems via redundant load paths, Vermont Yankee has determined that any single failure during removal of the existing racks or installation of the new racks will not cause any uncontrolled tilting, rotation, swing, or dropping of the racks.

It is, however, Vermont Yankee's intention to initially relocate two existing PAR racks to facilitate the installation of the first NES rack. Due to the extent of the modification required to upgrade the PAR racks to meet the redundancy requirements, this relocation will be done consistent with the requirements of Section 5.1 of NUREG-0612 for a nonsingle failure-proof lift, wherein a load drop analysis will be performed for a limited lift of an empty existing PAR rack. No racks will be moved over. irradiated fuel or other spent fuel racks during this relocation. Additionally, approved plant procedures will ensure that this limited lift is equal to or less than the analyzed condition. The lifting device to be used in this limited lift is the original vertical lifting device supplied by PAR for installation of these racks.

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i CLARIFICATION 6 State plans for rack procurement and use (e.g., procure all racks from one vendor, and install within two to three years).

RESPONSE

1 Vermont Yankee has a signed contractual agreement with Nuclear Energy Services, Inc., of Danbury, Connecticut to fabricate ten apent fuel racks.

The current schedule calls for delivery to Vermont Yankee of the first rack in April 1987 and the final rack in August 1987. As stated in Vermont Yankee's submittal of November 24, 1986, the first rack is scheduled to be installed in May 1987, with the remaining nine racks to be stored on-site until work load permits their installation.

It is Vermont Yankee's intention at this time to install the remaining spent fuel racks prior to the 1989 r0 fueling outage presently scheduled for February 1989.

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