ML20206M771
| ML20206M771 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 05/11/1999 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20206M764 | List: |
| References | |
| NUDOCS 9905170050 | |
| Download: ML20206M771 (2) | |
Text
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Waag g
i UNITED STATES j
NUCLEAR REGULATORY COMMISSION "g
j WASHINGTON, D.C. 30086-0001
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELIEF REQUEST FROM ASME CODE SECTION XI REQUIREMENTS ENTERGY OPERATIONS. INC.
ARKANSAS NUCLEAR ONE. UNIT NOS.1 AND 2 DOCKET NOS. 50-313 AND 50-368
1.0 INTRODUCTION
Pursuant to Title 10 of the Code of Federal Reaulations (10 CFR), Section 50.55a(g), the inservice inspection (ISI) of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code) Class MC and CC components shall be performed in accordance with Section XI of the ASME Code and applicable addenda, except where relief has been granted by the Commission pursuant to 10 CFR 50.55a(g)(6)(l). Section 50.55a(a)(3) states that alternatives to the requirements of paragraph (g) may be used, when authorized by the Nuclear Regulatory Commission (NRC) if (i) the proposed alternatives would provide an acceptable level of quality and safety or (ii) compliance with the specified requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.
As published in the Federal Reaister (61 FR 41303, dated August 8,1996), the NRC announced an amendment to its regulation in 10 CFR Part 50, Section 50.55a (rule). The rule incorporated, by reference, the 1992 Edition with 1992 Addenda of Subsections IWE and IWL of Section XI of the ASME Code. Subsections IWE and lWL provide the requirements for ISI of Class CC (concrete containments) and Class MC (metallic containments) of light-water cooled power plants. The effective date for the amended rule was September 9,1996, and requires licensees to incorporate the new requirements into their ISI plans and complete the first containment inspection by September 9,2001. However, a licensee may submit a request for relief from one or more requirements of the regulation (or the endorsed Code requirements) with proper justification.
In accordance with 10 CFR 50.55a(g)(6)(ii)(B), all licensees shall implement the inservice examinations specified for the first period of the first inspection interval in Subsection IWE,
" Requirements for Class MC and Metallic Liners of Class CC Concrete Components of l
Light-Water Cooled Plants," of the 1992 Edition with the 1992 Addenda in conjunction with the l
requirements of 10 CFR 50.55a(b)(2)(ix) by September 9,2001. Licensees shall also implement the inservice examinations that correspond to the number of years of operation that are specified in Subsection lWL, " Requirements for Class CC Concrete Components of Light-Water Cooled Plants," of the 1992 Edition with the 1992 Addenda in conjunction with the requirements of 10 CFR 50.55a(b)(2)(ix) by September 9,2001.
4 Enclosure 9905170050 990511 PDR ADOCK 05000313 P
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. By letter dated April 1,1999, Entergy Operations, Inc. (EOl, the licensee), submitted a request for relief from certain requirements of the ASME Code,Section XI, for Arkansas Nuclear One, Unit Nos.1 and 2 (ANO-1, ANO-2). The staff's safety evaluation of EOl's request is provided herein.
2.0 EVALUATION To comply with the expedited examination of containment required by 10 CFR 50.55a (g)(6)(li)(B), licensees must perform visual examinations of Class MC components per the requirements of Subsection IWE, and visual examinations on Class CC components per the J requirements of Subsection lWL. Paragraph lWL-2310 invokes paragraph IWA 2210, requiring specific minimum illumination and maximum direct examination distance for all concrete surfaces.
The licensee has proposed an alternative to the requirements for the measurement of illumination and examination distance for visual examinations. The visual examinations on containment are performed to determine if damage or degradation, including cracks, wear, corrosion, erosion, or other physical damage, warrant additional evaluation or repair of the structure. In order for the visual examinations to be performed in such a way as to detect critical flaws, proper lighting is essential. The licensee has provided an attemative to Code requirements that uses a combination of character-and workmanship-based samples to a
determine the resolution required to ensure that indications that might challenge containment integrity are detectable. Paragraph IWL-3111, Acceptance of Concrete, requires that the Responsible Engineer determine what surface conditions are acceptable and ensure there is no evidence of damage or degradation sufficient to warrant further evaluation or repair. Therefore, the licensee's Responsible Engineer will identify the minimum flaw size (indications of interest) required to be detected, in order to detect concrete indications (degradations) that could be detrimental to the containment integrity, the staff recommends, but does not require, the ute of a guideline developed by the American Concrete Institute (ACl), ACI 349.3R-96," Evaluation of Existing Nuclear Safety Related Concrete Structures." The use of this standard will eliminate the subjective judgement of the Responsible Engineer. For remote visual examinations, procedures and equipment used will be demonstrated to be capable of detecting and resolving these indications. The licensee will maintain a record of the demonstration performed.
While the use of the licensee's proposed attemative does not result in a quantitative evaluation of the illumination, it provides a method to verify that the indications of interest are visually detectable. The staff determined that samples representing these indications provide an appropriate simulation and concludes that visual verification, via direct or remote means, provides sufficient evidence of adequate illumination and examination distance.
3.0 CONCLUSION
The staff has evaluated the information contained in the licensee's April 1,1999, submittal for i
ANO 1 and ANO-2. On the basis of the preceding evaluation, the staff concludes that the proposed attemative contained in Alternative Examination 99-0-001 provides an acceptable level of quality and safety and, therefore, the licensee's proposed attemative is authorized pursuant to 10 CFR 50.55a(a)(3)(i).
Principle Contributor: N. Hilton Date: May.11, 1999
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