ML20215K715
| ML20215K715 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 05/07/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20215K698 | List: |
| References | |
| NUDOCS 8705110312 | |
| Download: ML20215K715 (3) | |
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UNITED STATES
'3 NUCLEAR REGULATORY COMMISSION 4
..j WASHINGTON, D. C. 20555 9...../
'S SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION CONCERNING RELIEF FROM ASME CODE SECTION XI INSERVICE INSPECTION REQUIREMENTS FOR CATEGORY B-J WELDS CONNECTICUT YANKEE ATOMIC POWER COMPANY HADDAM NECK PLANT DOCKET N0. 50-213
1.0 BACKGROUND
By letter dated September 16, 1986, Connecticut Yankee Atomic Power Company (the licensee) requested relief from certain Code Category B-J weld in-service inspection requirements of the 1980 Addenda of Section XI of the ASME Code at the Haddan Neck Power Plant. The licensee submitted additional information by letter dated January 26, 1987 in response to a request from the staff dated November 6,1986. This report provides an evaluation of the licensee's request, supporting information, and alternative examinations or tests, as well as the staff's basis for granting the request pursuant to 10CFR50.55a(g)(6)(1).
2.0 EVALUATION OF RELIEF REQUEST Relief Request 1-0: Class 1, Items B9.10 and 89.30, Category B-J, Pressure Retaining Welds in Piping The subject welds are listed in Table 1 of the September 16, 1986 submittal.
Code Examination Requirement The Code (Table IWB-2500-1) requires volumetric and surface examinations of the piping weld for a nominal pipe size greater than 4 inches. As permitted by 10 CFR 50.55a(b)(2)(ii), the licensee has ele:ted to determine the extent of examination for Class 1 piping by the requirements of Tables IWB-2500 and IWP-2600, Category B-J of the 1974 Edition through Summer 1975 Addenda of the Code.
Code Relief Request Relief is requested from performing the inservice volumetric examination of the inaccessible portions of the subject welds.
Licensee Basis for Relief The arrangements and details of the Class 1 piping systems and components were designed and fabricated before the examination requirements of 870511o312 870507 PDR ADOCK 05000213 G
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6 Section XI of the Code were formalized. Generally, limitations exist at all fitting-to-fitting welds such as elbow-to-tee, elbow-to-valve, reducer-to-valve, etc., where geometry and sometimes surface conditions preclude ultrasonic coupling or access for the required scan length. The limitations exist to a lesser degree at pipe-to-fitting welds, where ex-aminations can only be fully performed from the pipe side. The fitting geometry limits or even precludes examination from the fitting side.
In most cases, examinations in these areas were accomplished as a best effort attempt to cover as much of the Code required area or volume (generally, the weld and base metal for one wall thickness "T" on each side) as is possible. The examination of the weld, heat affected zone, and base metal for one "T" on the pipe side can be achieved by scanning from the pipe side of the weld. Some coverage of the base metal on the fitting or component side may be achieved during this pipe side scan.
A description of the limitation or obstruction of each of the subject welds is provided in the January 26, 1987 submittal. Also, an estimate of the percentage of the Code-required volumetric examination that was completed on each of the subject welds is provided for most of the subject welds in the January 26, 1987 submittal.
Licensee Proposed Alternative Examinations A.
The subject welds received a full surface examination and ultrasonic examination to the full extent practical, in accordance with Section XI.
Any advances in ultrasonic technology will be evaluated to determine its application for achieving maximum volume coverage and results.
B.
Inservice sy ten leakage tests were performed per Category B-P, IWB-2500-1 of the Code.
3.0 CONCLUSION
The subject welds cannot be completely examined volumetrically because of geometric limitations or obstructions. The licensee examined the full thickness of the weld to one wall thickness on each side of the weld. The Code requires only the volumetric examination of one-third of the thickness of the weld at the inner diameter (IC) to 1 inch on each side of the weld.
Furthermore, the licensee has performed a 0 ultrasonic scan of most of the subject welds and the licensee has performed volumetric examinations on pipes less than 4-inch nominal pipe size. Thus, the licensee has attempted to perform inspections beyond the Code requirements.
For welds 12-4 and 12-5 in Table 1 of the September 16, 1986 submittal, relief is requested for the steam generator nozzle-to-safe end welds.
However, relief has been granted by the staff for these two welds under Category B-F (see Amendment No. 37 to the facility cperating license).
Thus, the submitted request for relief should not include these two welds.
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The licensee has performed volumetric examinations of the subject welds to the maximum extent possible due to geometric limitations or obstructions.
Although some Code-required volume was not accessible for examination, the licensee generally examined more volume of materials than that required by the Code. Thus, the volumetric examinations performed by the licensee adequate to provide assurance of the structural integrity of the subject welds. Relief from the volumetric examination of the inaccessible portions of the subject welds may be granted as requested.
The relief granted remains in effect for the second ten-year inspection interval ending on January 1,1988, unless revised or modified prior to the end of the interval.
4.0 ACKNOWLEDGEMENT This Safety Evaluation was prepared by S. Lee, PAEB, DPWRL-A.
Dated: May 7,1987
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