ML14188B691
| ML14188B691 | |
| Person / Time | |
|---|---|
| Site: | Robinson  |
| Issue date: | 04/02/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML14188B690 | List: |
| References | |
| NUDOCS 9004110080 | |
| Download: ML14188B691 (5) | |
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'UNITED STATES Ar NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REGARDING THE REQUESTS FOR RELIEF FROM SECTION XI EXAMINATION REQUIREMENTS CAROLINA POWER & LIGHT COMPANY H.B. ROBINSON STEAM ELECTRIC PLANT, UNIT NO. 2 DOCKET NO. 50-261 I.
BACKGROUND INFORMATION Technical Specification 4.0.1 for the H. B. Robinson Steam Electric Plant, Unit No. 2, states that inservice examinations of ASME Code Class 1, 2, and 3 components shall be performed in accordance with Section XI of the ASME Code except where specific written relief has been granted by the Commission.
By letter dated February 1, 1989, Carolina Power & Light Compary (the licensee) submitted Relief Requests Nos. 19 and 20 which determined that the examination requirements of Section XI for the reactor vessel, the pressurizer, and the steam generator cladding and the regenerative heat exchanger welds were impractical to perform at H. B.
Robinson Steam Electric Plant, Unit No. 2. Relief Request No. 19 applies to the First Ten-Year Interval and was contained in an Inservice Inspection Summary Report submitted to Region II on January 13, 1983.
Relief Request No. 20 applies to the Second Ten-Year Interval.
The information provided by the licensee is evaluated herein to determine if the necessary findings can be made to grant the relief requested by the licensee.
II. EVALUATION OF REQUESTS A.
RELIEF REQUEST NO. 19
- 1. Code Relief Request:
Eliminate visual, surface, and volumetric examination (as applicable).
9004110080 900402 PEIR ADOCK 05000261 FDC
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- 2.
Code Requirement:
(First 10-Year Inspection Interval)
ASME Code Section XI, 1974 Edition through Summer 1975 Addenda Table IWB-2600 Item No. Category Component Method Extent Reactor Vessel B1.13 B-I-1 Closure Head
- 1) Visual &
6 Patches Cladding Surface, or
- 2) Volumetric Reactor Vessel B1.14 B-I-1 Vessel Clad-Visual 6 Patches ding Pressurizer B2.9 B-I-2 Vessel Clad-Visual 1 Patch ding Steam Generator A, B, and C B3.8 B-I-2 Vessel Clad-Visual 1 Patch ding each man way
- 3. Licensee's Alternative Examinations:
None
- 4.
Licensee's Basis for Relief Request:
a)
These examinations have been eliminated from later ASME Code Editions and Addenda.
b) These are high radiation areas (as high as 300 mr/min) and personnel exposure would be high (estimated 2100 mr).
c) Relief is requested based on previous examinations performed during the first 10-year interval and ALARA considerations.
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- 5. Staff Evaluation and
Conclusions:
The Code requirement to examine the cladding patches in the reactor vessel, pressurizer, and steam generators was intended to determine the cladding's resistance to cracking and thereby exposing the ferritic base material of the components to a corrosive environment. To comply with the requirements of the 1974 Edition of Section XI entailed exposure of examination personnel to high radiation areas, especially that of the reactor vessel closure head. This examination was deemed impractical when the useful informa tion gained or increased plant safety was weighed against the burden placed on the licensee. Other examinations such as nozzle-to-vessel welds and flange-to-vessel welds provide more meaningful information regarding the cladding integrity than that of Examination Categories B-I-1 and B-I-2. This require ment was deleted in later editions of Section XI for reasons cited above. The staff, therefore, concludes that relief from the examination requirements for the reactor vessel, pressurizer, and steam generators may be granted as requested.
B. Relief Request No. 20
- 1. Code Relief Request:
Relief is requested from volumetric and surface examination re quirements of the regenerative heat exchanger and nozzle welds.
- 2. Code Requirements:
ASME Code Section XI, 1977 Edition through Summer 1978 Addenda, Table IWB-2500-1, Item #B2.51, B2.60, and B3.150 require volumetric examination.
Table IWC-2500-1, Item C1.10 and C1.30 require volumetric examination.
Exam Category B-B, Pressure-Retaining Welds in Vessels other than Reactor Vessels, Item #82.51 and B2.60.
Exam Category B-D, Full Penetration Welds of Nozzles in Vessels, Item #B3.150 Exam Category C-A, Pressure-Retaining Welds in Pressure Vessel, Item #C1.10-C1.30
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- 3. Licensee's Alternative Examination:
VT-2 during hydrostatic test at the end of the interval.
- 4. Licensee's Basis for Relief:
Based on radiation exposures in the area, i.e., general area of 3 to 4 R/hr and 9 to 10 R/hr on contact with hot spots of 12 to 15 R/hr, and in view of the fact that the previous examination revealed no indications, relief is requested from volumetric and surface examinations of the regenerative heat exchanger shell and nozzles.
- 5. Staff Evaluation and
Conclusions:
The high levels of radiation that would be encountered by examination personnel make the Code requirements impractical to perform. The magnitude of the radiation fields at the regenera tive heat exchanger have increased to a level that the licensee's proposed alternative visual (VT-2) examination during the hydrostatic test is the most practical method of assessing the weld's structural integrity. The staff, therefore, concludes that relief from the volumetric and surface examinations required by Section XI for the regenerative heat exchanger welds may be granted as requested.
Principal Contributor: George Johnson Dated:
April 2, 1990
DISTRIBUTION Docket File NRC PDR Local PDR S. Varga 14-E-4 G. Lainas 14-H-3 E. Adensam 14-B-20 P. Anderson 14-B-20 C. Cheng 9-H-15 D. Verrelli RH R. Lo 14-B-20 OGC (For inform. Only) 15-B-18 E. Jordan MNBB-3302 ACRS (10)
P-315 Robinson File