BECO-LTR-96-035, Forwards Revised Table in Support of Plant Relief Request - 9 Re Reactor Pressure Vessel nozzle-to-shell & Nozzle Inner Radius Exams

Forwards Revised Table in Support of Plant Relief Request - 9 Re Reactor Pressure Vessel nozzle-to-shell & Nozzle Inner Radius Exams

ML20107J117
Person / Time
Site:	Pilgrim
Issue date:	04/16/1996
From:	Boulette E BOSTON EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
BECO-LTR-96-035, BECO-LTR-96-35, TAC-M93398, NUDOCS 9604240335
Download: ML20107J117 (3)

Text

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, . 10CFR50.55a  !

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Boston Edison l Pilgrim Nuclear Power Station

. Rocky Hill Road l Plymouth, Massachusetts 02360 I

1 E. T. Boulette, PhD  !

Senior Vice President-Nuclear )

April 16, 1996 BECo Ltr.#96 035 l

U.S. Nuclear Regulatory Commission )

Attention: Document Control Desk l l

Washington, DC 20555 l' Docket No. 50-293 License No. DPR-35 1 l

Revised Table Related to RPV Nozzle Examinations Pilarim Plant Relief Reauest-9. Third Ten-Year ISI Proaram. (TAC NO. M93398) i l

The attachment to this letter provides a revised table in support of Pilgrim Plant Relief Request - 9 related to the reactor pressure vessel nozzle-to-shell and nozzle inner radius examinations. This )

revision is the result of clarifications to the original relief request discussed in a telephone call on l April 3,1996, with the NRC, Boston Edison, and the contractor, Idaho National Engineering  !

Laboratory.

E. T. Boulette wgi/radmisc/isirai2

Attachment:

Nozzle to Vessel and Inner Radius Examinations (Revised).

cc: Mr. R. Eaton, Project Manager Division of Reactor Projects - 1/II Mail Stop: 14D1 U. S. Nuclear Regulatory Commission 1 White Flint North 11555 Rockville Pike Rockville, MD 20852 U.S. Nuclear Regulatory Commission Region 1 475 Allendale Road King of Prussia, PA 19406 Senior Resident inspector fl Pilgrim Nuclear Power Station 0I 9 A O D f;'1 -.

96o4240335 960416 I PDR ADOCK 05000293 p PDR

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. ATTACHMENT NOZZLE TO VESSEL AND INNER RADIUS EXAMINATIONS (Revised) l (This table supersedes Enclosure M to BECo letter 96-009, dated February 15,1996, i The vertical bar indicates clarifications in response to NRC/BECo telephone call dated April 3,1996.)

The 21 nozzles addressed in this relief request have examination limitations primarily due to the interference created by the biological shield wall. Smaller diameter nozzles such as the RPV-N9A&B, and N-10 have additional limitations due to the small outside radius of the nozz!s. See the attached list (Appendix I) of nozzles for % of volume examined and the reasons stated for all tlmitations involving each nozzle.

Note: The LMiogical shield wall only offers a 1 inch to 1 1/4 inch clearance from the vessel outer surface. In this area, there is permanently installed insulation that is impractical to remove.

Anoendix 1 NOZZLES  % VOLUME EXAMINED REASONS FOR LIMITATIONS RPV-N1A 81.39 % The biological shield wall interferes with 45' RPV-N1B 71.39 % and 60' axial scan from shell plate surface (Recirculation) scanning towards the nozzle (1/2t zone shell side). This same interference results in loss of coverage with O' at the edge of the 1/2t zone on the shell side.

For nozzle RPV-N1B an additional 10% of volume cannot be scanned due to the thermal pad that is installed. The thermal pad is approximately 2"x2"in size. The clockwise and counterclockwise scens of the inner radius of ,

RPV N18-NIR results in 90% coverage due to the thermal pad. For RPV-N1A-NIR a 100%

coverage is obtainable on the inner radius.

RPV-N2A-K 64.24 % The biological shield wall interferes with the (Recirculation) following:

. 10% of the volume of the 1/2t zone shell side with 0* exam, e 5% of the volume of the 1/2t zone shell side with the 45' axial scan with the sound beam oriented towards the shell.

. 60% loss of volume of the weld and 1/2t zone when scanning with the 45' axial towards the nozzle side, e 10% loss of volume of the 1/2t zone when scanning with the 60* axial towards the shell side, e 75% of the volume of the weld and 1/2t zone when scanning with the 60' axial from shell to nozzle side.

RPV-N4A B 98.53 % 10% of the volume is not covered with the 60*

(Feedwater) axial scan when scanning from the nozzle side i

towards the shell due to *.he biological shield wall.

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Appendix I (Continu:d)

NOZZLEIS  % VOLUME EXAMINED REASONS FOR LIMITATIONS i RPV-N6A&B 97.81 % The biological shield wall interferes with the (Core Spray) following exams:

5% of the volume with the 60* axial scan i

from the nozzle side towards the shell. I

. 10% of the volume with the 60* axial scan  !

from the shell side towards the nozzle.  !

! RPV-N9A&B 63.52 % The small outside radius of the nozzle limits the 1

(Jet Pump 0,45' and 60* scans. The nozzle is scanned Instrumentation) on the shell side up to this radius and from the

! edge of the radius towards the shell side.

! RPV-N10 82.79 % The biological shield wall interferes with the ,

l (CRD) following examinations: )

l . 10% of the volume with the 45' axial scan i with the sound beam oriented towards the l shell side.

i .

45% of the volume with the 60* axial scan j with the sound beam oriented towards the shell side.

The small outer radius of the nozzle also interferes with the following exams:

! . 5% of the volume with the 45' axial scan

. when the sound beam is oriented towards j

the nozzle side.

j -

20% of the volume with the 60' axial scan

{ when the sound beam is oriented towards

g the nozzle side.

,