BECO-86-132, Application for Amend to License DPR-35,changing Tech Specs to Permit Use of Addl Neutron Control Matl Due to Use of New Hybrid Control Rod Blades.Fee Paid

Application for Amend to License DPR-35,changing Tech Specs to Permit Use of Addl Neutron Control Matl Due to Use of New Hybrid Control Rod Blades.Fee Paid

ML20209F315
Person / Time
Site:	Pilgrim
Issue date:	09/05/1986
From:	Howard J BOSTON EDISON CO.
To:	Zwolinski J Office of Nuclear Reactor Regulation
Shared Package
ML20209F319	List: BECO-86-132, Application for Amend to License DPR-35,changing Tech Specs to Permit Use of Addl Neutron Control Matl Due to Use of New Hybrid Control Rod Blades.Fee Paid ML20209F379
References
BECO-86-132, NUDOCS 8609120117
Download: ML20209F315 (4)

Text

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EOSTON EDISON COMPANY 500 SOYLaTON STattT EOsTON, MAssAcNussTTs 02199

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Proposed Change 86-08 Mr. John A. Zwolinski, Director BWR Project Directorate #1 Division of Licensing Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555 License DPR-35 Docket 50-293 Proposed _ Technical Specification Change, Hybrid Control Rod Blades

Dear Str:

Pursuant to 10CFR50.90, the Boston Edison Company hereby proposes the attached modification to Appendix A of Operating License DPR-35. This proposed modification to the Pilgrim Nuclear Power Station Technical Specifications adds a reference to the additional neutron control material that will beBecause used in the core as a result of the use of new hybrid control rod blades.

our current plans are to install some of these new hybrid control rod blades during our current refueling outage, we request your expeditious review and approval of this proposed change.

If you require any further information concerning this submittal, please contact us.

Very truly yours, DMV:Isd k '

Attachment Three originals and 37 copies Commonwealth of Massachusetts County of Suffolk Then personally appeared before me, J. Edward Howard, who, being duly sworn, did state that he is Vice-President, Nuclear Engineering and Quality Assurance Fl y

of Boston Edison Company and that he is duly authorized to execute and file nIso the submittal contained herein in the name and on behalf of Bos. ton Edison

@8' Company and that the statements in said submittal are tru p,to;Jhe;best of his gg knowledge and belief. . Ag*

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, BOSTON EDISON COMPANY Page 2 cc: Mr. Robert M. Hallisey, Director Radiation Control Program Mass. Dept. of Public Health 150 Tremont Street F-7 Boston, MA 02111

l Proposed Technical Specification Change, Hybrid Control Rod Blades Proposed Change It is proposed that Pilgrim Nuclear Power Station (PHPS) Technical Specification Section 5.2.B (Page 206m) be revised as shown on the attached to include a reference to the use of the control material Hafnium in the PNPS reactor core.

Reason For4'hange During the current refueling outage at PNPS, it is planned to replace some of the control rod blades wit" new hybrid control rod blades. The principle change in these hybrid control rod blades is the use of Hafnlum absorber rods in place of the Boron-Carbide absorber rods in the outer regions of the control blade. The use of these Hafnium rods in the high neutron flux regions of the blade reduces the impact that Boron-10 depletion and swelling have on blade lifetime. Other changes in the hybrid control rod blades include the reduction of Cobalt-bearing stellite material in the pins and rollers, reduction in the blade sheath thickness to preserve total control blade weight, and increased purity of stainless steel 304 used as tubing material for the Boron-Carbide absorber rods. This combination of design changes is expected to increase control rod blade lifetime by an average of forty percent and reduce absorber rod tube cracking.

Safety Considerations The proposed change does not compromise the safety of PNPS because the new hybrid control rod blade has been designed to have the same form, fit, and function as the current blades in use at PNPS. As described below, the hybrid control rod blade meets all applicable design criteria. The generic safety evaluation contained in General Electric Company Topical Report NEDE-22290-A,

" Safety Evaluation of the General Electric Hybrid Control Rod Assembly," dated September 1983, has been reviewed and approved for use by the NRC.

This proposed change has been reviewed and approved by the Operations Review Committee and reviewed by the Nuclear Safety Review and Audit Committee.

Significant Hazards Consideration As documented in General Electric Topical Report NEDE-22290-A, " Safety Evaluation of the General Electric Hybrid Control Rod Assembly," dated September 1983, the new hybrid control rod blades have the following characteristics:

1. The mechanical, hydraullc, and thermal performance is equal to the present control blades.

2. The geometry of the new hybrid blade is not changed in any manner as to alter current interface relationships with fuel channels, fuel support castings, guide tubes, and control rod drive mechanisms.

3. The hybrid blade is capable of functioning in a reactor environment with the temperature and pressure transients encountered during normal, upset, emergency, and faulted conditions. Stresses and deformations resulting from those transients have been considered when determining the acceptability of the design.

4. The hybrid design is capable of withstanding the loading encountered during handling, shipping, anticipated activities during reactor operation, and environmentally induced loads.

5. The mechanical life of the hybrid control blade is reached either when (1) the internal Hellum pressure from the Boron-10 (neutron, alpha) reaction results in stresses in the absorber tube of the control rod reaching the most restrictive design limit which is evaluated against Article NG-3000 of the ASME Boller and Pressure Vessel Code,Section III, or (2) the local Boron-10 depletion exceeds 70 percent resulting in irradiation induced Boron-Carbide swelling and stresses in the absorber rod tubing.

6. The nuclear life of the hybrid control blade is reached when the Boron-10 depletion results in a 10 percent loss in relative control rod worth in the top quarter section of the blade.

For these reasons, it is determined that operation of PNPS in accordance with the proposed amendment would not (1) involve a significant increase in the probability or consequences of an accident previously evaluated; or (2) create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) Involve a significant reduction in a margin of safety. Thus, the proposed amendment poses no significant hazards involvement.

Schedule of Change The proposed amendment will become effective immediately upon receipt of approval by the Commission.

Fee Determination Pursuant to 10CFR170.12(c), this submittal includes a check for $150.00 in payment of the application fee.