ML20127P015

Forwards Response to Open Items Contained in NRC SE for Amends 99 & 92 to Licenses DPR-42 & DPR-60,respectively Re single-failure-proof Crane upgrade.TN-40 Special Lifting Devices Will Be Inspected Prior to Each Use

ML20127P015
Person / Time
Site:	Prairie Island
Issue date:	01/25/1993
From:	Parker T NORTHERN STATES POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
TAC-M81883, TAC-M81884, NUDOCS 9302010159
Download: ML20127P015 (7)

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Northern States Power Company 414 Neollet Man -

Minneapons. Minnesota 55401

, Telephone (612) 330 5500 January 25, 1993 U S Nuclear Regulatory Commission Attn: Document Control Deck Washington, DC 20555 PRAIRIE ISLAND NUCLEAR CENERATING PLANT Docket Nos. 50 282 License Nos. DPR-42 50 306 DPR 60 Response to Single-Failure-Proof Crane Upgrade License Amendment Safety Evaluation Open Items TAC N)s. M81883 and M81884 The attached information is provided in response to open items contained in the NRC Safety Evaluation for Prairie Island License Amendments 99 and 92 issued July 9,1992. Amendments 99 and 92 revised the Prairie Island Technical Specifications to eliminate cask handling restrictions and replace them with requirements for the use of a single-failure-proof handling system in the handling of heavy loads.

Attachment 1 describes the test plan for the special lifting device to be-utilized in handling the TN-40 spent fuel storage casks at Prairie Island.

Attachment 2 provides the justification. for the dynamic load factor. utilized  ;

in the structural analysis of the TN-40 spe.cial lifting device. '

Our October 4,1991 License Amendment Reques,t, which proposed the Technical Specification changes issued by Amendment 99 and 92, stated that the special-lifting device to be utilized in handling the TN-40 spent storage casks would be-designed to meet the requirements of the 1978-revision of ANSI N14.6. -The:  ;

October 4, 1991 License Amendment Request was in error. As stated in Section 2.1 of Transnuclear Specification- E-12261, Revision 0, " Design Criteria for j]

Lifting System for TN-40 Dry Cask Storage Cask at Prairie Island"', which was-transmitted to the NRC by our letter dated February 3,1992, the special lifting device-to be utilized in handling the-TN-40 spent storage. casks is-being designed in accordance with the requirements of ANSI N14.61986.

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apologize for any-inconvenience this error may'have caused.  ?

Our October 4, 1991, License Amendment Request stated that we Mould be unabic l

to comply with the special lift device load test-requirements of ANSI N14.6 and that any load testing performed per ANSI N14.6-would be performed at the 125% level. .That exception to ANSI N14.6 is no longer valid, the special lifting device for the TN-40 cask will be load tested in accordance with the requirements of ANSI N14,6,1986.

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- Pago- 2 January 25, 1993 - Northem States Power Comparri The specific NRC commitments contained in this transmittal are listed in Attachment 1 . Please contact Gene Eckholt (612-388-1121, ext. 4663) if.you have any questions related to-the information provided.

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. Thomas M Parker

' Director Nuclear Licensing c: Regional Administrator - Region III, NRC Senior Resident Inspector, NRC NRR Project Manager, NRC J E Silberg Attachments:

1. Testing of TN-40 Cask Special Lifting Device.

2. Justification of TN-40 Cask Special Lifting Device Dynamic Load Factor.

3. NRC Commitments Contained in This Transmittal

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ATTACHMENT 1-Testint Plan for the TN-40 Cask Special Lifting Device As stated in our October 4', 1991 License Amendment Request, the'special lifting device to be utilized in handling the TN-40 spent fuel a;orage casks at Prairie Island will meet the requirements of ANSI N14.6, " Standard for-

• Special Lifting Devices for Shipping Containers Weighing 10,000 Pounds:or More for Nuclear . Materials", as outlined in guideline (1)(a) of Section 5.1.6 of -

NUREG-0612. 1Run testing plan for the TN-40 special lifting device is ~ outlined below. Except as noted below, testins of the TN-40 special lifting device will conform with the requirements of ANSI N14.6, 1986. j ACCEPTANCE TESTINC Initial acceptance testing of the special lif ting device for the TN-40 cask will be conducted in accordance with the requirements Sections 6.2, 7.1 and 7.3 of ANSI N14.6, 1986.

Load Testing Section 7.1 of ANSI N14.6 defines the requirements for special lifting devices for critical loads. Section 7.1(1) of ANSI N14.6 allows the use of special-lifting devices, like the TN 40 special lifting device, that utilize load bearing members with increased stress factors-for handling the critical load-rather than dual load paths. Section 7.3 of ANSI N14.6 states that if.c special-lifting device is' designed with increased. stress design factors instead of dual load _ paths, acceptance testing shall be_ conducted in.

accordance with 6.2.1, except that the test load shall be three. times the weight that the device is to support rather than: the 150% requirement of-Section 6.2.1. -The acceptance _ testing of the special lifting device for the-Prairia Island TN-40 casks will be performed at three times the weight the device is to support.

Section 6.2 of Transnuclear Specification-E-12261, Revision 0, " Design Criteria-for Lifting System for TN-40 Dry Storage Cask at Prairie Island",

which was transmitted to the NRC by our letter dated February 3,1992, states that the TN 40 special' lift device.will be load tested to 150%_of the design 4

load prior to shipping. That statement was in error. As stated above, :ne-TN.40 cask special lifting device will be acceptance tested at three ,mes the .l weight that~the-device is to support.

- ' Functional Testine _

Non-load bearing functioning parts of the TN-40 special lif ting device will be :

tested, as. prescribed by Section 6.2.3 of ANSI N14.6, 1986, prior to initial use of the device.

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Page 2 of 3 TESTING TO VERIFY- CONTINUING COMPLI ANCE Testing of the special-lifting device for the.TN-40' cask to verify continuing compliance with the requirements of ANSI N14.6_will be conducted as described below. The plan for periodic testing and inspection the TN 40fspecial lifting device is based, with some exceptions, on the requirements of Sections 6.3 and 7.3 of ANSI N14.6, 1986.

Annual Testine Section 7.3 of ANSI N14.6, 1986 states that annual testing shall be' conducted in accordance with Section 6.3.1 of ANSI N14.6 except that the device shall be subjected to'three times the weight that the device is_to support. Section-6,3.1(2) of ANSI N14.6, 1986 allows, in cases where surface cleanliness and-conditions permit, the annual load testing requirements to be replaced with:

dimensional testing, visual inspection, and nondestructive testing of' major.

load carrying welds and; critical areas in accordance with-Section 6.5 of ANSI- ,

N14.6, 1986. The annual testing of the special lifting device for-the Prairie Island TN-40 casks will be performed in accordance with Section 6.3.1(2),

therefore, no annual load testing will be performed.

The functional testing of the TN-40 special lifting device, prescribed in-Section 6.2.3 of ANSI "14.6, 1986 for acceptance testing, will be repeated on an annual basis per Section 6.3.4 of ANSI N14.6, 1986. -

Sections 6.3.1 and 6.3.4 of ANSI N14.6, 1986 specify'that the period for annual testing of special lifting devices not. exceed 14 months. Section 4.0 of the Prairie Island Technical Specifications sllows the time interval between surveillance tests to-be adjusted plus r r minus(25% to- accommodate normal test schedules. Surveillance testing performed at Prairie Island, including testing nco specifically required by Technical Specifications, is-scheduled using this allowance. For consistency, the TN-40 special lifting device annual testing will be scheduled as part of the plant surveillance-program using the plus or minus 25% allowance ~. The surveillance will be scheduled to be competed every.12 months, but the interval could-be extended to a maximum interval -of 15 months if scheduling or other conflicts. arise.

The ar.nual testing required by Sections 6.3.1(2) and 6.3.4 of ANSI N14.6,-1986 will not be performed on an annual basis if the TN-40 lifting device is_not to be used~for a period exceeding one year. In that case, the testing required by. Sections 6.3.1(2) and 6.3.4 will be performed before returning the device to service.

Section 6.3.8 of ANSI N14.6, 1986 prescribes that each special lifting device be tagged or the record system updated after annual testing, indicating the expiration date of the validity of that test. Ar'noted above, surveillance-testing of the_TN-40 special lifting device wilt be scheduled and controlled by tho' plant' surveillance program. This program will cnsure that the annual.

testing will be performed per the required schedule and that the results of the annual testing will be properly documented.

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' Additional lead Testine .

The TN 40 special-lifting device will be load tested as prescribed in_Section-6.2.1;of ANSI 14.6, 1986 after any of the following:

1. Major' maintenance or alterations, as defined in Section 6.3.2 of ANSI _

N14.6, 1986,

2. An incident in which any of the load-bearing components of.the TN-40 special lif ting device may have been subjected to stresses substantially in -

excess of those for which it was previously quali.fied or

3. An incident that may have caused permanent distortion of its load bearing ,

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Additional Functional Testing

'Per Section 6.3.5 of ANSI N14.6, 1986, the functional testing prescribed in Section 6.2.3 of AhSI-N14.6, 1986 for acceptance-testing, will be repeated following any incident in which repairs or alterations have been required.on non-load-bearing functioning components or in which the TN-40_special lifting device has suffered detectable distortion. H Visual-Insoection i Section 6.3.6 of ANSI N14.6, 1986 presccibes that special lifting devices _bE visually inspected by operating personnel for indications of. damage or deformation prior to each use. 'Section 6.3.7 of ANSI N14.6,E1986 prescribes that special lifting devices be visually inspected by maintenance or other non-operating personnel at intervals not .to exceed three months for indications.of: damage or deformation.

The visual inspections _ prescribed by Sections 6.3.6 and 6.3.7 appear to be-designed to address concerns with a special' lifting device which'is'used on a-  !

continuing basis and, as 'such, could experience _ significant degradation 'over time from usage. The visualiinspection by' operating personnel would; identify any degradation which may occur between mort thorough quarterly inspections.

Because the.TN-40 special lifting-device is only expected toLbe used onTthe average of twice per year, the quarterly visual inspection re'quirements prescribed by Section 6.3.7 are inappropriate. _Therefore, the requirements.of:

Sections 6.3.6 and 6.3.7 will be combined; and the TN-40 special. lifting device;will be visually inspected by maintenance or non-operating personnel prior to each use of the lifting device.

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PRAIRIE ISLAND NUCLEAR GENERATING PLANT-ATTACHMENT 2 Justification of TN-40 Cask Special Liftine Device Dynamic load Factor A dynamic load factor of 0.05 was used in th6 structural anelysis of the-special lifting device to be utilized in handling the TN 40 spent fuel storage casks at Prairie Island. The dynamic load factor was obtained by mu?tiplying the maximum hoisting speed for the upgraded Prairie Island auxiliary building crane (5 ft/ min) by 0,005 (0.5%). This it recommended in the Crane Manufacturers Association of America (CMAA) Specification #70, 1988 revision, to calculate the Hoist. Load Factor for a crane. The result, 0.025, was doubled to provide an additional safety margin. -}

Crane Manufacturers Association of America Specification #70, 1988 revision, also recommends that the Holst Load Factor not be less than 0.15 for the crane -

design. However, the Crane Manufacturers Association of-America minimum Holst I Load Factor value is not applicable for the Prairie Island TN-40 special lifting device design because the Crane Manufacturers Association of America minimum Hoist Load Factor pcrtains to the crane structure which is-designed.

with a stress factor of 5 to ultimate; while the Prairie Island TN-40 special lifting device is designed with stress factors of 6 to yield and 10 to ultimate.

Additionally, as outlined below, the upgraded Prairie Island auxiliary building crane is designed for very smooth operation which will minimize dynamic loads on the lift beam due to accelerations or decelerations.

Tha crane is equipped with a DC hoist control with a stepless drive which provides for smooth acceleration and deceleration. It also requires less maximum motor torque than AC type drives.

The impact forces imparted on the lif t beam are further minimized by the following: 1 e The maximum hoist speed that will be used when handling a TN-40 storage:

cask is-very slow (5~ft/ min).

• The hoist is equipped with an energy absorbing torque limiter, which-limits the torque to 130% of the design value, e The hoist is equipped with a load cell which automatically stops the crane if a load of 125% of the rated static load'is dctected.

• Strict administrative controls are exercised over all' crane operations Only qualified and trained operators nill operate the crane.

• The crane wire cable will also provide damping effects which will reduce the dynamic load amplification factor.

• Two separate magnetic brakes are provided on the crtue as well as regenerative braking. .Each magnetic brake providra a braking force of' 150% of rated load and are timed (s(quenced) to act in series. .Thus, the sequenced magnetic brakes and the regenerative motor brake assures that smooth lowering and hoisting' speeds can be maintained regardless of the load on the hook. ,

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' ATTACHMENT 3 ,J NRC Commitments Contained in This Transmittal l

1. Initial ~ acceptance testing of the specialnlifting: device forfthe TN.40tcask: -

will be conducted in accordance_with the requirements Sections 6.2, 7,1 and; 7.3 of ANSI N14.6,;1986. The acceptance testing-of the-special lifting '

device for the ' Prairie Island TN-40 casks willL be. performed-at!three timesL " ' .

the weight the device is to support.-

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2. Non-load-bearing functioning parts of the TN 40 special lifting devic lwill- -

be tested, as prescribed by Section 6.2.3~of ANSI N14.6, 1986, prior-to1 initial use of the device.

3. The annual testing of the special lifting device for the Prairie Island TNk 40 casks will be performed in accordance wich'Section 6.3.1(2) of ANSI N14.6, 1986, no annual load testing will be performed.

4. The functional testing of the TN 40_ special lifting device, prescribed irt ,

Section 6.2.3 of ANSI N14.6, 1986 for acceptance testing,~will be_ repeated on an annual basis per Section 6.3.4 of ANSI N14.6, 1986.

5. The TN 40 special lifting _ device annual testing will be scheduled _as part--

cf the plant surveillance program using the Technical Specification plus or minus 25% allowance. The survnill.ance will be scheduled-en be competed:

every 12 months, but the interval could be extended to a maximum interval:

of 15 months if scheduling or other conflicts arise.

6. The annual testing required by Sections 6.3.1(2) and 6.3.4 of ANSI-N14.6, 1986 will not be performed on an annual basis. if the TN-40 lifting device :

0 is not to be used for a p'eriod exceeding one_ pear. In-that case, the. .

testing required by Sections 6,3.1(2)- and 6.3.4 -will be performed before -

returning the device to service.

7.TheTNe40specialliftingdevicewillbeloadtestedas-prescribed [in- 14 Section 6.2.1 of ANSI 14.6, 1986 after any of;the following:

a. Major maintenance or alterations, as defined _ in! Section 6.3.2; of, ANSI.

N14.6, 1986,

b. An incident in which any of the -load-bearing components of the TN special lifting devi.ce may have-been subjected'to stresses substantially.

in excess of those for wh2ch it was previously qualified, or c..An incident that may have caused permanent distortion of its load--

bearing parts.

8. Per Section 6.3.5 of ANSI N14.6, 1986, the functional, testing prescribedlin Section 6'.2.3 of ANSI N14.6,' 1966 for acceptance testing,- willlbe repeated.

following any incident in which repairs or alterations have been. required on non-load-bearing-functioning components.or in which the TN 40'special:

p .liftirg device has suffered detectable distortion.

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~9 . i*he'TN-40 special lifting uevice will-be visuelly' inspected.by maintenance. -

or. non' operating -personnel prior to each use of the liftiv.g Jevi.ce.

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