ML20137U039
| ML20137U039 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 04/14/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20137U034 | List: |
| References | |
| NUDOCS 9704160252 | |
| Download: ML20137U039 (4) | |
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- UNITED STATES
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NUCLEAR REGULATORY COMMISSION i.
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WASHINGTON, D.C. 20066 4001 j-SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION 4
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~ RELATED TO AMENDMENT NO. 93 TO FACILITY OPERATING LICENSE NO. NPF ENTERGY OPERATIONS. INC.
i RIVER BEND STATION. UNIT 1 DOCKET NO. 50-458 i
1.0 INTRODUCTION
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By application dated January 10, 1997, Entergy Operations, Inc. (the licensee) requested changes to the Technical Specifications (TSs) (Appendix A to Facility Operating License No. NPF-47) for the River Bend Station, Unit 1.
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The proposed changes would revise the pressure-temperature (P-T) limits for heatup, cooldown, and inservice leak and hydrostatic testing to provide new j
j limits that are valid to.12 effective full power years-(EFPY).
2.0 BACKGROUND
4-The staff evaluates the P-T limits based on the following NRC regulations and 1
guidance:
Appendix G to 10 CFR Part 50; Generic Letters (GL) 88-11 and 92-01; l
Regulatory Guide (RG) 1.99, Rev. 2; and Standard Review Plan (SRP)
Section 5.3.2.
Appendix G to 10 CFR Part 50 requires that P-T limits for the reactor vessel must be at least as conservative as those obtained by j
Appendix G to Section XI of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code. GL 88-11 requires that licensees use 2
the methods in RG 1.99, Rev. 2, to predict the effect of neutron irradiation i
on the adjusted reference temperature (ART) of reactor vessel materials. The i
ART is defined as the sum of initial nil-ductility transition reference l
temperature (RT caused by neutron irradiation, anIr) of the material, the increase in RT*in the prediction j
a margin to account for uncertainties i
method.
The increase in RT j
factor and a fluence factor., is calculated from the product of a chemistry i
1 The chemistry factor may be calculated using credible surveillance data, obtained by the licensee's surveillance program, as directed by Position 2 of 4
RG 1.99, Rev. 2.
If credible surveillance data are not available, the chemistry factor is calculated dependent upon the amount of copper and nickel in.the vessel material as specified in Table 1 of RG 1.99, Rev. 2.
GL 92-01 i
requires licensees to submit reactor vessel materials data, which the staff j
uses in the review of the P-T limits submittals.
t SRP 5.3.2 provides guidance on calculation of the P-T limits using linear 4
i elastic fracture mechanics methodology specified in Appendix G to Section III of the ASME Code.
The linear elastic fracture mechanics methodology
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postulates sharp surface defects that are normal to the direction of maximum i
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stress and have a depth of one-fourth of the reactor vessel beltline thickness j
(1/4T) and a length of 1-1/2 times the beltline thickness. The critical locations in the vessel for this methodology are the 1/4T and 3/4T locations, which correspond to the maximum depth of the postulated inside surface and outside surface defects, respectively.
3.0 EVALUATION For the River Bend Station reactor vessel, the licensee determined that the most limiting material at the 1/4T and 3/4T locations is the axial weld that i
was fabricated using tandem electrodes. This weld was fabricated using weld wire heat SP6756. The licensee calculated an ART of 72.3*F at the 1/4T i
location and 55.2'F at the 3/4T locapsionag12EFPY. The neutron fluence used in10,theAjTcalculationwas1.79x10. n/cm at the 1/4T location and 0.93 x n/cm at the 3/4T location. The initial RT for the limiting weld was
-50*F.
The margin term used in calculating theTRT for the limiting weld was 56*F.
The staff performed an independent calculation of the ART values for the i
limiting material using the methodology in RG 1.99, Rev. 2.
Based on these
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calculations, the staff verifted that the licensee's limiting material for the River Bend Station reactor vessel is the axial weld that was fabricated using tandem electrodes (heat SP6756). The staff's calculated ART value for the j-limiting material agreed with the licensee's calculated ART value.
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Substituting the ART values for River Bend Station into equations in SRP j
5.3.2, the staff verified that the proposed P-T limits satisfy the requirements in Paragraph IV.A.2 of Appendix G of 10 CFR Part 50.
In addition to beltline materials, Appendix G of 10 CFR Part 50 also imposes a j
minimum temperature at the closure head flange based on the reference when the
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pressure exceeds 20% of the preservice system hydrostatic test pressure, the temperature of the closure flange regions highly stressed by the bolt preload must exceed the reference temperature of the material in those regions by at least 120*F for normal operation and by 90*F for hydrostatic pressure tests and leak tests.
Based on the flange RT of 10*F for River Bend Station, the staff has determined that the proposed,P-T limits have satisfied the requirement for the closure flange region during normal operation and inservice leak and hydrostatic testing.
The staff has performed an independent analysis to verify the licensee's proposed P-T limits. The staff concludes that the proposed P-T limits for heatup, cooldown, inservice-leak and hydrostatic testing and core criticality are acceptable to 12 EFPY since the limits conform to the requirements of Appendix G of 10 CFR Part 50 and GL 88-11.
Based on the above, the proposed P-T limits and proposed TSs are acceptable.
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4.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Louisiana State Official was notified of the proposed issuance of the amendment.
had no comments.
The State official
5.0 ENVIRONMENTAL CONSIDERATION
i The amendment changes a requirement with respect to installation or use of a 4
facility component located within the restricted area as defined in 10 CFR Part 20.
The NRC 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 i
The Commission has previously issued a proposed finding that the exposure.
amendment involves no significant hazards consideration, and there has been no i
i public comment on such finding (62 FR 8798).
Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c) 9).
environme(ntal assessment need be prepar(ed in connection the amendment.
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6.0 CONCLUSION
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The Commission has concluded, based on the considerations discussed above, that:
(1)'there is reasonable assu mnce that the health and safet J
public will not be endangered by operation in the proposed manner,y of the activities will be conducted in compliance with the Commission's reg (ulations,
- 2) such and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
7.0 REFERENCES
1.
Regulatory Guide 1.99, Radiation Embrittlement of Reactor Yessel Materials, Revision 2, May 1988 2.
NUREG-0800, Standard Review Plan, Section 5.3.2:
Pressure-Temperature Limits 3.
Code of Federal Regulations, Title 10. Part 50, Appendix G, Fracture Toughness Requirements 4.
Generic Letter 88-11, NRC Position on Radiation Embrittlement of Reactor Vessel Materials and its Impact on Plant Operations, July 12, 1988 5.
ASME Boiler and Pressure Vessel Code,Section III, Appendix G for Nuclear Power Plant Components, Division 1, " Protection Against Nonductile Failure"
6.
January 10, 1997, Letter from J. R. McGaha, Jr. to USNRC Document Contr i
Desk,
Subject:
River Bend Station Unit 1 Licensee Amendment Request 96-09.
change te Technical Specifications 3.4.11, "RCS Pressure and Temperature (P-T vs. RCS Pressure"J Limits," Figure 3.4.11-1, " Minimum Temperature Required 7.
October 22, 1996, Letter from G. Stevens (Structural Integrity Associates) to E. J. Zoch (Entergy Operations, Inc.)
Subject:
(12 EFPY) P-T Curves for River Bend Station.
Revised Principal Contributor:
A. D. Lee Date: April 14, 1997