ML20114C310

Requests Several Listed Exemptions from Requirements of 10CFR34.Expedient Approval Would Be Appreciated

ML20114C310
Person / Time
Site:	Millstone
Issue date:	07/07/1992
From:	Plumstead W FLUOR DANIEL, INC.
To:	Steven Baggett NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20114C257	List: ML20114C296 ML20114C310
References
NUDOCS 9209020114
Download: ML20114C310 (3)

Text

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July 7, 1992 i

Steve Baggett, Section Leader Nuclear Materials Safety Section Nuclear Materials safety and Sa2eguards Branch Division of Radiation Safety and Safeguards USNRC Washington, DC 20555

Reference:

South Carolina Radioactive Material Licensa No. 043 Gentlemen:

SUBJECT:

REQUEST TOR EXEMPTION OF DURING RADIOGRAPHY Fluor Daniel is providing radiographic examination services for the Millstone Unit 2 Steam Generator Replacement Program. We are working at the Connecticut location in accordance with ' *: South Carolina License No. 043 and the " RECOGNITION OF RECIPROCITY" letter dated March 13, 1992 from yorr office.

This is to requect several exemptions from requirements of 10 CFR 34.

1. An, one-time only, exemption from surveying the source guide tube after radiographic exposure per 10 CFR 34.43 and Fluor Daniel Operating and Emergency Procedure No. 102 paragraph 4.2.11 and No.

103 paragraph 4.1.3.

2. An, one-time only, exemption from the limitation of three guide tubes per Fluor Daniel Operating and Emergency Procedure No. 102 paragraph 4.1.3.

3. An exemption from adjusting the " Restricted Area" perimeters per Fluor Daniel Operating and Emergency Procedure No. 104 paragraph 4.1.10.

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l LE rsonnel acccss to the girth weld inside the steam generator is

.ow and difficult due to space restrictions. personnel staytimes

,ould be reduced or eliminated due to anticipated high temperature jaociated with the minimum weld preheat of 250 degrees F during Ilding and postweld heat treat (pWHT) temperature of 1100-1200 green F.

ldiation surveys will be performed on all sides of the source vice and the length of the flexible guide tube to the rigid tube nnector (inside the steam generator) . The " highest reading" on ch source device mill be verified after each exposure before oceeding to the next exposure or before disconnecting the source

vice cables, whichever is appropriate.

e exemption frcm limitations of a maximum of three source guide be sections is needed to drive the source to the maximum distrace I

om the source device for the proper exposure. The mawiant stance is approximately 40 feet. All three cobalt 60 source

-vices a're equipped with 50 feet control (drive) cables which t

ovides sufficient additional drive cable to prevent extending the ive cable past the drive gear, exemption fron adjasting the " Restricted Area" perimeters based curvey readings is inappropriate in the higher background idiation areas n rmal to operating nuclear power facilities.

-erefore, we believe that it is reasonable to position the iestricted Area" at the perimeter distance calculated for a jrticular nstant.

radioactive material source strength and its gamma il{

estructive exe.mination plan has been developed to minimize al exposure to the harsh temperature environment and reduce the 1 path time during radiography of the steam generator girth weld.

3) 100 curie cobalt 60 sources will be exposed concurrently to total exposure time required for radiographic examination of the Jenerator girth weld, ber of '-ines that radiography personnel vill have to enter the

enerator will be minimized by prepositioning twenty-seven (27)

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i NRC Page 2 UJIONALE

.. Personnel access to the girth wold inside the steam generator is slow and difficult due to space testrictions. Personnel staytimes should be reduced or eliminated due to anticipated high temperature associated with the minimum weld preheat of 250 degrees F during welding and postweld heat treat (PWHT) temperature of 1100-1200 degrees F.

Radiation surveys will be performed on all sides of the source device and the length of the flexible guide tube to the rigid tube connector (inside the steam generator) . The " highest reading" on each source device will be verified after each exposure before proceeding to the next exposure or before disconnecting the source device cables, whichever is appropriate.

2. The exemption from limitations of a maximum of three source guide tube sections is needed to drive the source to the maximum distance from the source device for the proper exposure. The maximum distance is approximately 40 feet. All three cobalt 60 source devices are equipped with 50 feet control (drive) cables which provides suf ficient additional drive cable to prevent extending the drive cable past the drivo getr.

3. An exemption from adjusting the " Restricted Area" perimeters based on curvey readings is inapprbpriate in the higher background radiation areas normal to operati ~ nuclear power facilities.

Therefore, we believe that it it reasonable to position the

" Restricted Area" at the parimeter distance calculated for a particular radioactive material source strength and its gamma constant.

NDE PIAN A nondestructive examination plan has been developed to minimize personnel exposure to the harsh temperature environment and reduce the critical path time during radiography of the steam generator girth weld.

Three (3) 100 curie cobalt 60 sources will be exposed concurrently to A

reduce total exposure time required for radiographic examination of the steam generator girth weld.

The number of times that radiography personnel will have to enter the steam generator will be minimized by prepositioning twenty-ceven (27) to 'd Gr -2. sea 10nd1ENO3 cOmd WCdJ CEZE006 01 LI:CI 26. EE 70f a

sta.inless (SG; steel rigid source guide tubes inside each steam generator Rigid guide tube connections will be located below the SG access hole line-of-sight and attached to the generator shroud with tube blocks.

Eighteen (18) guide tubes will be located at one SG access opening for exposures using two source devices. Nine (9) guide tubes will be located at the SG accass located 180 degrees from the other SG access opening.

The rigid guide tube ends at the weld will be attached to positioning clamps for the focal locations required to complete the girth weld radiography (Attachment A). The rigid guide tubes should remain in position until radiography of two intermediate weld thicknesses, a completed weld prior to PWHT, and the final weld after PWHT is complete.

NRC Page 3 Each source device (camera) will be connected to the appropriate rigid guide tube by a flexible guide tube. The connections will be identified sequentially in three sets of nine (9) guide tubes that correlate with the specific exposures at three selected locations approximately 120 degree positions around the girth weld circumference. Nine (9) such exposure setups sequenced around the circumference will complete the weld (Attachment B) .

Personnel assigned to perform radiographic examination of the SG girth weld will receive approximately four (4) hours of specialized training on the SG nockup. Training will includo full radiographic exposure simulation using a training camera and dummy source. Each radiographer will perform a practical extmination to demonstrate an understanding of the radiographic requirerents and demonstrate the capability to work within the access restrictions, s

REOUEST We would appreciate your expedient approval of

, exemption. this request for Thank you for consideration of this request. Please contact me or leave messages at (803) 281-5337, for any needed clarification or questions.

Verv truly yours A

O/kAc  %&

, William C. Plumstead Radiation Safety Officer cy: L.E. Hartsell D.C. Harris G.C. Hanvey r0 % 3rz-1 EC i n 19 CO eon N W0ii EIE;Crs 01 6T:0; 26. EE int