ML20212M199
| ML20212M199 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 02/27/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20212M198 | List: |
| References | |
| NUDOCS 8703110271 | |
| Download: ML20212M199 (2) | |
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UNITED STATES 8
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 98 TO FACILITY OPERATING LICENSE NO. OPR-35 BOSTON EDISON COMPANY PILGRIM NUCLEAR POWER STATION DOCKET NO. 50-293
1.0 INTRODUCTION
By letter dated September 5, 1986 (Ref. 1) from J. E. Edward, Boston Edison Company (BECo), to J. A. Zwolinski, NRC, BECo proposed changes to the Pilgrim Nuclear Power Station (PNPS) Unit 1 Technical Specifications to incorporate a boron-carbide absorber rods with hafnium absorber rods (PAR) placement of the new design of control blades. The new design provides for re in the outer regions of the control blade. The new design is intended to increase control rod assembly life and eliminate intergranular stress corrosion cracking (IGSCC) of absorber tubes containing boron carbide.
The major design changes of the control blades are as follows:
1.
Replacement of B C absorber rods with solid hafnium absorber rods at the 4
tip positions of each blade to increase control rod assembly life.
2.
The use of an improved P C absorber rod tube material from presently used 4
counercial grade type 304 stainless steel to a high purity type 304 stainless steel to avoid IGSCC during the lifetime of the assembly.
In addition, there are other associated material and dimensional changes including a reduction in sheeth wall thickness to preserve total control blade weight and changes from stellite to PH13-8 Mo and Inconel X-750 of the pin and roller materials to eliminate cobalt-hearing stellite materials (Ref. P.1 PROPOSED CHANGES TO TECHNICAL SPFCIFICATIONS SECTION 5.2.B Current Proposed The reactor core shall contain The reactor core shall contain 145 cruciform-shaped control 145 cruciform-shapped control rods. The control material rods. The control materials shall be boron carbide powder shall be either boron carbide (BC)compactedtoapproximately powder (BC1compactedto 4
4 70% of theoretical density approximately 70% of theoretical density or a combination of boron carbide powder and solid Hafnium.
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. 2.0 EVALUATION The new GE BWR hybrid control rod blades using hafnium control materials and its associated structural and geometry changes has been previously reviewed by staff and approved based on approved methodologies and parameters in the approved GE topical report NEDE-22?90-A, " Safety Evaluation of the General Electric Mybrid 1 Control Rod Assenhly" dated September 1983.(Ref. 2).
l Therefore, the staff concludes that the use of the control material hafnium and its associated structural materials and geometry changes are acceptable for Reload 7 operation and the proposed technical specification changes are acceptable.
3.0 ENVIRONMENTAL CONSIDERATf0N This amendment involves a change to a requirement with respect to the l
' installation or use of a facility component located within the restricted area as defined in 10 CFR Part 70. The staff has determined that the amendment
' involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that this amendment involves no significant hazards consideration and there has been no public comment on such finding. Accordinoly, this amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(cif91.
Pursuant to 10 CFR 51.22(b) no environmental impact statement nor environmental assessment need be prepared in connection with the issuance of this amendment.
4.0 CONCLU$f0N 1
The staff has concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Commission's regulations and the issuance of this amendment will not be inimical to the common defense and security nor to the health and safety of the public.
5.0 REFERENCES
1.
Letter from J. E. Howard, Boston Edison Company, to J. A. Zwolinski, NRC, September 5, 1986.
2.
Safety Evaluation of the General Electric Hybrid Control Rod Assembly, NEDE-22290-A dated September 1983.
Principal Contributor:
U. Cheh Dated:
February 27,1987 i
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