ML103190466
| ML103190466 | |
| Person / Time | |
|---|---|
| Issue date: | 04/30/2011 |
| From: | Madhumita Sircar NRC/RES/DE/SGSEB |
| To: | |
| Bayssie Mekonen/RES 251-7489 | |
| Shared Package | |
| ML081560497 | List: |
| References | |
| DG-1197 RG 1.90 | |
| Download: ML103190466 (2) | |
Text
REGULATORY ANALYSIS DRAFT REGULATORY GUIDE (DG) - 1197 INSERVICE INSPECTION OF PRESTRESSED CONCRETE CONTAINMENT STRUCTURES WITH GROUTED TENDONS (Proposed Revision 2 of Regulatory Guide 1.90, dated August 1977)
Statement of the Problem The U.S. Nuclear Regulatory Commission (NRC) issued Regulatory Guide 1.90, Inservice Inspection of Prestressed Concrete Containment Structures with Grouted Tendons, Revision 1, in August 1977 to provide recommendations for inservice inspection (ISI) and quality standards that the staff considered acceptable for the use of Portland cement grout as the corrosion inhibitor for prestressing tendons in prestressed concrete containment.
Since the issuance of Regulatory Guide 1.90, Revision 1, the industry and the NRC have been involved in license submittals and reviews, research, and testing to determine and evaluate the effectiveness of ISI programs. Containment tendon ISI guidance has been discussed during the review of licensing issues. Only two nuclear power plants in the United States have used grouted tendons: Three Mile Island Nuclear Station, Unit 2 (which is permanently shut down), and H.B. Robinson Steam Electric Plant. However, at least one future applicant has indicated an intention to use grouted tendons in its containment. The NRC issued Regulatory Guide 1.90, Revision 1, over 30 years ago, and new applicants may use grouted tendons. Therefore, a revision to this regulatory guidance is necessary to include updated ISI information.
Objective The objective of this regulatory action is to update the NRCs guidance with respect to the use of portland cement grout as the corrosion inhibitor for prestressing tendons in prestressed concrete containments. The update aids applicants and licensees by endorsing the requirements in Division 2, Code for Concrete Reactor Vessels and Containments, of Section III, Rules for Construction of Nuclear Power Plant Components, of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (ASME Code) and in providing current staff positions, which will lead to increased regulatory efficiency and effectiveness.
Alternative Approaches The NRC staff considered the following alternative approaches:
Do not revise Regulatory Guide 1.90.
Revise Regulatory Guide 1.90 or issue a new regulatory guide.
Alternative 1: Do Not Revise Regulatory Guide 1.90 Under this alternative, the NRC would not revise (or issue additional) guidance, and the current guidance would be retained. If the NRC does not take action, there would not be any changes in costs or benefit to the public, licensees, or the NRC. However, the no-action alternative would not address additional knowledge gained since the issuance of the original guide. The NRC would continue to review
each application on a case-by-case basis. This alternative provides a baseline condition from which any other alternatives will be assessed.
Alternative 2: Revise Regulatory Guide 1.90 or Issue a New Regulatory Guide Under this alternative, the NRC would revise Regulatory Guide 1.90 with the updated requirements in Division 2 of Section III of the ASME Code and current staff positions.
One benefit of this action is that it would enhance reactor safety and improve regulatory effectiveness by including the latest requirements in Division 2 of Section III of the ASME Code and current staff positions.
The impact to the NRC would be the costs associated with preparing and issuing the regulatory guide revision. The impact to the public and the stakeholders would be the voluntary costs associated with reviewing and providing comments to the NRC during the public comment period. The value to the NRC staff and its applicants would be the benefits associated with enhanced efficiency and effectiveness in using a common guidance document for updated staff positions for license applications and other interactions between the NRC and its regulated entities.
Conclusion Based on this regulatory analysis, the NRC staff recommends revision of Regulatory Guide 1.90.
The staff concludes that the proposed action would improve regulatory effectiveness and lead to a more efficient regulatory process while maintaining or enhancing safety.
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