ML18012A519
| ML18012A519 | |
| Person / Time | |
|---|---|
| Site: | Harris  |
| Issue date: | 02/24/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML18012A518 | List: |
| References | |
| NUDOCS 9702260265 | |
| Download: ML18012A519 (4) | |
Text
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO XXX T
N NPF-CAROLINA POWER 8( LIGHT C MPANY SHEARON HARRIS NUCLEAR POWER PLANT DOCKET NO.
0-400 1.0
~INTR QUCTltlN By letter dated December 30, 1996, the licensee submitted slight changes to some of the best estimate chemistry values for the beltline materials.
These changes resulted from cooperative data sharing activities in response to Generic Letter 92-01, Revision 1, Supplement 1.
Specifically, the licensee reviewed available reactor pressure vessel (RPV) beltline material data, and identified plants that have the same weld heat identifications as those contained in the Harris vessel (sister plants).
In addition to sharing data with sister plants, the licensee also shared data with the Westinghouse Owners Group (WOG) in order to determine best estimate chemistry for the beltline materials.
As a result of these assessments, the nickel content of the limiting material increased from 0.45K to 0.46K.
This slight change in nickel content does not affect the pressure-temperature (P-T) limits in the Shearon Harris Technical Specifications (TS).
- However, some documentation changes are necessary.
The current amendment request also revises the associated Bases to retlect chemistry revisions and minor material property changes for the beltline weld fabricated from weld wire heat 5P6771.
In addition, the licensee submitted revisions to the Bases in order to comply with 10 CFR 50, Appendix G rule changes.
The staff evaluates the P-T limits based on the following NRC regulations and guidance:
Appendix G to 10 CFR Part 50; Generic Letters (GL) 88-11 and 92-01; 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 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 the methods in RG 1.99, Rev.
2, to predict the eff'ect of neutron irradiation on the adjusted reference temperature (ART) of reactor vessel materials.
The ART is defined as the sum of initial nil-ductility transition reference temperature (RT>>) of the material, the increase in RTN>> caused by neutron irradiation, and a margin to account for uncertainties in the prediction method.
The increase in RT>>
is calculated from the product of a chemistry factor and a fluence factor.
The chemistry factor may be calculated using credible surveillance data, obtained by the licensee's surveillance
- program, as directed by Position 2 of A'02hw0aiS 9voa24 PDR ADOCK 05000400 P
PDR ATTACHMENT 1
Regulatory Guide (RG) 1.99, Rev.
Z. 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 requires licensees.to submit reactor vessel materials
- data, which the staff uses in the review of the P-T limits submittals.
SRP 5.3.2 provides guidance on calculation of the P-T limits using linear elastic fracture mechanics methodology specified in Appendix G to Section III of the ASME Code.
<<ie linear elastic fracture mechanics methodology postulates sharp surface defects that are normal to the direction of maximum stress and have a depth of one-fourth of the reactor vessel beltline thickness (1/4T) and a length of l-l/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 de-".". of the postulated inside surface and outside surface defects, respectively.
- 2. 0 EVALUATION The limiting material in the Shearon Harris reactor vessel is the intermediate shell plate that was fabricated using heat number A9153-1.
The licensee determined that the slight increase in the nickel content of the limiting material from 0.45K to 0.46K did not affect the P-T limits.
The staff performed independent calculations of the chemistry factor (CF) values for the beltline materials using the revised best estimate chemistry and the methodology in RG 1.99, Revision 2.
Based on these calculations, the staff verified that the CF of'he limiting material remained unchanged.
Since the revised best estimate chemistry does not affect the limiting material, it will not affect the P-T limits.
Therefore, Amendment 38 dated August 20, 1993 which approved the P-T limits curves to 11 effective full power years (EFPY) remains valid.
Some beltline materials experienced a slight reduction in copper and nickel content which resulted in a
CF that remained the same or could have been reduced.
For those CF values that could have been
- reduced, the licensee elected to maintain the current conservative CF value.
Assessment of the newly acquired data resulted in the determination of a revised dropweight temperature (T >>) for the weld fabricated from weld wire heat 5P6771.
The original T va Pue was -20'F, and the revised value is -80'F as determined from the unirradiated surveillance weldment test data.
- However, the revised Type value does not effect the initial reference temperature since it is based on the surveillance weldment temperature for the Charpy 50 ft-lb value minus 60'F.
The current initial reference temperature value of -20'F remains valid, and the weld is not the limiting reactor vessel beltline material.
Therefore, the P-T limits are not affected.
The staff found the proposed revisions to the applicable Bases sections for In-Service Leak
& Hydrotests (ISLH), and the ASME Code Section to be used for the development of P-T limits acceptable since the revisions are consistent with the amended rule for 10 CFR 50, Appendix G, that was effective January 18, 1996.
The staff also noted that the revisions to the best estimate chemistry do not affect any significant results relative to the withdrawal schedule or testing of any surveillance capsules.
- 3. 0 CONCLUSION The staff has performed an independent calculation of chemistry factors for the reactor vessel beltline materials.
The staff verified that the CF of the limiting material remained unchanged.
Consequently, the P-T limits remain unchanged.
The staff concludes that the proposed documentation changes may be incorporated in the Shearon Harris Technical Specifications.
The proposed changes to the Bases section of the Technical Specifications are consistent with the revised best estimate chemistries, and are also acceptable.
4.0 REFERENCES
1.
Regulatory Guide 1.99. Radiation Embrittlement of Reactor Vessel 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 ASME Boiler and Pressure Vessel
- Code,Section XI, Division 1, "Rules for Inservice Inspection of Nuclear Power Plant Components" December 30, 1996, Letter from W.
R. Robinson to USNRC Document Control Desk,
Subject:
Shearon Harris Nuclear Power Plant Request f'r License Amendment RCS Pressure/Temperature Limits 7.
August 20, 1993, Letter from N. Le to W. S. Orser,
Subject:
Issuance of Amendment No.
38 To Facility Operating License No.
NPF-63 Regarding Technical Specifications Change to Pressure-Temperature Limits-Shearon Harris Nuclear Power Plant, Unit 1 (TAC NO. M85876) 8.
November 16, 1995, Letter from J.
W. Donahue for W.
R. Robinson to USNRC Document Control Desk,
Subject:
Shearon Harris Nuclear Power Plant Response to Generic Letter 92-01, Revision 1, Supplement 1,
"Reactor Vessel Structural Integrity"
SALP INP FACILITY NAME:
Shearon Harris Nuclear Power Plant
SUMMARY
F REVIEW A TIVITIE The staff reviewed the licensee's proposed documentation changes to the pressure-temperature (P-T) limits sections of the Shearon Harris Technical Specifications.
The documentation changes reflect slightly revised best estimate chemistries that resulted from data sharing activities.
The staff calculated chemistry factors (CFs) for each beltline material using the revised best estimate chemistries in order to verify that the CF for the limiting material, and consequently the P-T limits, remained unchanged.
NARRATIVE DI SI N
F LICEN E PERF RMANCE-F N TI NAI AREA SAFETY AS ESSMENT UALITY VERIFICATION The licensee's assessment of the revised best estimate chemistry as it relates to the P-T limits was clear,
- concise, and detailed.
Documentation changes to the Technical Specifications were clearly marked in the submittal.
The licensee included marked up Technical Specification pages to enhance the clarity of the submittal.
The quality control in preparing the P-T limits submittal is excellent.
Author:
A. Lee 415-2735 ATTACHMENT 2