ML14297A097
| ML14297A097 | |
| Person / Time | |
|---|---|
| Issue date: | 01/04/2021 |
| From: | Stanley Gardocki, Liliana Ramadan NRC/RES/DE/RGDB |
| To: | |
| SJG1 | |
| Shared Package | |
| ML14281A067 | List: |
| References | |
| DG-1303 RG-1.009, Rev. 5 | |
| Download: ML14297A097 (6) | |
Text
REGULATORY ANALYSIS FOR DRAFT REGULATORY GUIDE (DG)-1303 APPLICATION AND TESTING OF SAFETY-RELATED DIESEL GENERATORS IN NUCLEAR POWER PLANTS (Proposed Revision 5 of Regulatory Guide 1.9, issued March 2007)
- 1. Introduction This document presents the regulatory analysis of the U.S. Nuclear Regulatory Commissions (NRCs) proposed revision of Regulatory Guide (RG) 1.9, Application and Testing of Safety-Related Diesel Generators in Nuclear Power Plants, The NRC is issuing Revision 5 of this RG to provide current guidance based on the generally accepted methods and procedures for emergency diesel generators (EDGs), combustion turbine generators (CTGs), and any other onsite alternate AC standby power supplies. Specifically, the onsite emergency alternating current (AC) standby power supplies should be properly qualified, have sufficient capacity and capability, adequate testing, and have the necessary reliability and availability to operate as required under all design conditions. This programmatic guidance is the result of lessons learned from NRC staff evaluations in support of license amendment review activities and inspections, industry operating experience review, design certification reviews, and Combined License (COL) application reviews.
- 2. Statement of the Problem The current application and testing criteria endorsed in RG 1.9 for EDGs used for emergency AC standby power supplies at nuclear power plants is out of date. Current guidance does not include specifications for supplies other than diesel generators, e.g., combustion turbine generators, and dam generators.
Lessons learned by the NRC staff evaluations of license amendment requests, site inspections, and industry operating experience has identified enhancements to the guidance that could improve the quality of the testing program by providing verification of the performance characteristics of EDGs used to provide emergency power to nuclear power plants. Industry has issued the following guidance documents for these emergency AC standby power supplies, that supersedes the existing guidance in RG 1.9 which endorses IEEE Std 387-1995:
IEEE Std 387-2017, IEEE Standard for Criteria for Diesel Generator Units Applied as Standby Power Supplies for Nuclear Power Generating Stations, and IEEE Std 2420-2019, IEEE Standard for Combustion Turbine-Generator Units Applied as Standby Power Supplies for Nuclear Power Generating Stations.
These updated standards delineate principle design criteria, qualification and testing guidelines to ensure EDGs and CTGs will meet the 10 CFR Part 50, Appendix A, General Design Criteria for Nuclear Power Plants, namely the requirements for electrical power systems (GDC 17).
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- 3. Objective The objective of this regulatory analysis is to assess the need to update the NRC guidance on the application and testing of safety-related standby power supplies in nuclear power generating stations.
- 4. Identification and Analysis of Alternative Approaches The NRC staff considered the following alternative approaches:
- 1. Do not revise Regulatory Guide 1.9
- 2. Withdraw Regulatory Guide 1.9
- 3. Revise Regulatory Guide 1.9 to address the current methods and procedures.
4.1 Alternative 1: Do Not Revise Regulatory Guide 1.9 Under alternative 1, the NRC would not revise this guidance. Licensees, COL holders, and applicants would continue to use the present version of RG 1.9. The NRC would continue to find the existing guidance acceptable. This alternative would not impose any additional costs for revising RG 1.9 on the public, applicants, licensees, COL holders, or the NRC. This is considered the no-action alternative and is the baseline against which the impacts of other alternatives are measured.
Under the "no action" alternative, there would be no cost to the NRC for revising the guide. However, the NRCs knowledge gained of the licensing and oversight processes, as well as the operational experiences and lessons learned from the last 20 years of industry practice would not be made available in the guidance. By not adding the additional guidance, the NRC staff may have to ask additional questions to applicants, COL holders, and licensees, resulting in longer times to complete new license and license amendment requests.
The no-action alternative would not improve the current guidance for testing EDGs used as safety related emergency AC power sources at nuclear power plants. Also, the current guidance does not address CTGs and other forms of AC power generators, e.g., dam generators, being used or proposed by nuclear power plants as emergency AC power sources.
4.2 Alternative 2: Withdraw Regulatory Guide 1.9 Withdrawing this RG would eliminate existing guidance on methods and procedures acceptable to the NRC for the testing of diesel generators used as emergency power sources.
Even though little NRC staff effort is needed to withdraw this RG, this option has no obvious benefit. The NRC staff would document a short evaluation of the withdrawal and then post in the Federal Register Notice.
Applicants, COLs, licensees, and NRC staff would both be burdened by a withdrawal.
Without acceptable guidance, they would have to propose and justify methods and procedures for testing new or replacement diesel generators. Then the NRC staff would be tasked to review and approve each alternate methods and procedures. These reviews may require extensive time and effort that potentially involve multiple rounds of questions to the applicant, COL holder,
Page 3 or licensee. These questions will impose a burden on the NRC staff in preparing them, reviewing them, and determining a path forward following review. Applicants, COL holders, and licensees would be burdened by having to respond to the questions. If additional questions are needed, it will extend the length of an application review and impact licensees schedules and workloads.
4.3 Alternative 3: Revise Regulatory Guide 1.9 Under this alternative, the NRC staff would revise RG 1.9 to reflect the current NRC staff recommendation for testing and validating safety related EDGs. This enhanced programmatic guidance is the result of lessons learned from license amendment review activities, inspections, and industry operating experience review and analysis by the NRC staff. In addition, RG 1.9 would be revised to include guidance for testing and validating safety related combustion turbine generators and other alternate AC power generators.
A revision to RG 1.9 would benefit the NRC staff, applicants, COL holders, and licensees by providing guidance based on current generally accepted methods and procedures for testing and validating emergency AC power generators. Specifically, RG 1.9 would be revised to stipulate that EDGs should be properly qualified, have sufficient capacity, and have the necessary reliability and availability to operate as required under all design conditions. A revision to RG 1.9 would endorse recent industry guidance that describes acceptable methods for application and testing criteria for emergency AC power generators as required by GDC 17.
Thereby, revising RG 1.9 would enhance regulatory stability. This additional guidance would be beneficial to the NRC staff as well as to the applicant, COL holder, or licensee by reducing or eliminating the need for multiple rounds of RAIs to determine if they meet current standards.
Application of the revision to RG 1.9 would be voluntary on the NRCs licensees, COL holders, and applicants. It would not impose new requirements or change existing regulations.
The staff anticipates that the impact on the industry of implementing the new guidance would be minimal and would be the voluntary costs of reviewing the issued RG 1.9 and the endorsed IEEE guidance. The impact to the NRC would be the costs associated with preparing and issuing the RG revision. The impact to the public would be the voluntary costs associated with reviewing and providing comments to NRC during the public comment period. The benefit to NRC staff, applicants, COL holders, and licensees would be enhanced efficiency and effectiveness in using a common guidance document as the technical basis for licensing actions. The proposed changes to the NRCs guidance are expected to reduce the number of future license amendments submitted to the NRC, without a reduction in safety. Specifically, the proposed changes would reduce the number of licensing actions submitted by applicants, COL holders, and licensees, resulting in less NRC Staff technical reviews and approvals.
For parties who are in the process of submitting an application to the NRC, the impact would be on the cost of addressing the aspects of the revisions to this guide.
- 5. Comparison of Alternatives This section compares the three alternatives against each other with respect to safety and resources of the NRC, licensees, COL holders, and applicants.
With respect to Alternative 1, not revising the RG will not increase safety because no change will be made to the existing guidance. The NRC staff, applicants, COL holders, and licensees will continue to use the current RG with additional requests for guidance from the
Page 4 applicants, COL holders, and licensees and extended review periods by the NRC staff. The failure to update the RG will cost nothing in the short term; however, it will result in extended review time for the NRC staff and additional work by licensees, COL holders, and applicants to address additional questions and testing requirements developed by the NRC staff. Regulatory guidance and stability will remain unchanged because the RG will remain unchanged. This "no action" alternative will continue the current level of predictability and transparency. However, given the NRCs expectation for future applications and licensee-initiated changes, the current guidance would be insufficient.
Withdrawing the RG will reduce the current level of safety because the withdrawal of the RG will eliminate active guidance for NRC staff, applicants, COL holders, and licensees who submit a license amendment request. This loss of regulatory guidance will also create the need for additional resource expenditures by the NRC staff, applicants, COL holders, and licensees because each licensing action would be reviewed on a case-by-case basis which will require more staff hours to evaluate and resolve. The lack of publicly available guidance will also adversely impact regulatory stability, predictability, public transparency, and public confidence by requiring a case-by-case evaluation of new or revised license amendments.
Revising the RG will enhance safety because the revision will incorporate the most current information into the NRC guidance on the application verification and testing of EDGs.
This should enhance the reliability of the EDGs and may improve plant safety. NRC resources are required to collate the information and develop a draft regulatory guide and supporting documents. This is a short time resource drain, but it should improve future NRC staff performance by reducing the time required for future reviews of EDG test results and equipment suitability verifications at nuclear power plants. NRC staff as well as applicants, COL holders, and licensees resource requirements should be reduced if the submitter follows the revised RG.
The NRC staff will not need to perform as detailed an assessment of the emergency AC power supply if the applicant, COL holder, or licensee follows the guidance in the revised RG.
Regulatory stability and predictability will be improved by revising the RG as well as enhanced public transparency and confidence because the revised RG will provide consistent guidance to all stakeholders and allow the public to better understand the NRC staff review process.
The staff finds that a revising RG 1.9 would provide acceptable guidance with respect to which changes are permissible without prior-NRC approval. In addition, the revision would increase regulatory effectiveness and efficiency. For example, the efficiency in NRCs licensing and oversight activities would increase by, bringing consistency to the guidance for GDC-17, and reducing the number of amendment requests from specific licensees and certificate holders, with no reduction in safety.
Based on this regulatory analysis, the NRC staff concludes that revision of RG 1.9 (Alternative 3) is the best alternative for providing NRC guidance on acceptable methods and procedures for testing safety-related EDGs, CTGs, and other alternate AC power supplies used for emergency AC power supplies in nuclear power plants for complying with the requirements of GDC-17. Alternative 3 would incorporate the NRCs knowledge of the licensing and oversight processes, the operational experiences and lessons learned from recent years of industry practice, as well as endorse Industry guidance for CTGs and other alternative power supplies, such as dams. The proposed revision will enhance an applicants ability to prepare submittals that meet the current generally-accepted standards, methods and procedures. An updated guide will reduce staff review time and the need for RAIs thus reducing costs to licensees, applicants, COL holders, and the NRC. The cost to NRC in revising the RG and to licensees, COL holders, and applicants in adapting to a revised RG are deemed to be far less than the
Page 5 benefits accrued by reducing the need for multiple rounds of questions and answers which can impose a significant cost burden on licensees, COL holders, applicants, and staff, and result in licensing delays.
- 6. Decision Rationale The three alternatives were compared against each other with respect to regulatory stability and predictability, public transparency and public confidence.
With respect to safety, insights garnered through practical experience or research and should not be ignored as would happen with Alternative 1 and 2. Whereas, alternative 3 would be superior to Alternative 1 and 2. It would update RG 1.9 to include revised industry standards, new industry standards, and procedures that would enhanced safety, improved clarity, reduce the uncertainties, and facilitate timeliness in the licensing process.
With regard to NRC resources, Alternative 3 represents the greatest initial cost to the NRC, which is attributable to the costs associated with preparing a revision to the RG. However, when considered over the lifetime of the RG and the potential for additional staff resources expenditures associated with evaluating submittals from applicants, COL holders, and licensees, the overall NRC cost of Alternative 3 is closer to or less than the overall cost of Alternatives 1 or 2. With regard to licensee, COL holder, and applicant resources, Alternative 3 results in the least costs. Without additional guidance, their submittals may be delayed because the NRC may have to issue RAIs, and applicants, COL holders, and licensees may have to perform additional analyses to address those RAIs. These additional activities would lead to increased costs to them and to the NRC for the staff time required to issue and review the RAIs.
By contrast, because Alternatives 1 and 2 would not reflect the current industry standard. NRCs reviews of the applicant, COL holder, and licensee submittals may be delayed because the NRC may have to issue requests for additional RAIs. And the applicants, COL holders, and licensees may have to perform additional analyses to address those RAIs. These additional RAIs and analyses would lead to increased costs and time delays.
Alternatives 1 and 2 would not reflect the revisions and new industry standards. As a result of withdrawal of the RG under Alternative 2, the content of future submittals could vary between applicants, COL holders, and licensees; thereby, making the NRC review more burdensome and time consuming. Delays and cost increases would more likely under Alternative 2 due to an increased number of RAIs resulting from the lack of guidance in the current edition of RG 1.9.
With regard to regulatory stability and predictability for current licensees, Alternative 1 would first appear to represent the most regulatory stability; inasmuch, as the current guidance would be maintained. However, given the NRCs expectation for future applications and licensee-initiated changes, the current guidance would be insufficient. Therefore, Alternative 1 and would not actually provide the best regulatory stability and predictability. Hence, Alternative 3 would provide the best regulatory stability and predictability, because the NRC would not be imposing adopting a revision of RG 1.9 on a licensee, the licensee would be voluntarily initiating a change in their best interest.
With regard to public transparency and public confidence, Alternative 3 would result in the highest level of transparency and public confidence. Incorporating the use of the current industry standards would enhance public confidence in the effectiveness and quality of the NRCs regulatory activities. By contrast, elimination of guidance for future licensees, COL holders, and applicants under Alternative 2 will result in regulatory instability and possible
Page 6 erosion of public confidence by a lack of transparent methods. Maintaining the existing guidance under Alternative 1 would be inconsistent with transparency, as it would erroneously suggest that the NRC continues to believe that the guidance in the current RG is acceptable for future applications for new and amended licenses. The dichotomy between the existing NRC guidance (out-of-date) and the current industry acceptable standard does not promote public confidence in the NRCs regulatory activities.
Therefore, with respect to regulatory stability and predictability, public transparency and public confidence, the NRC finds Alternative 3 to be in the best interest of the NRC, public, licensees, applicants, and COL holders.