ML23272A183
"Draft Meeting" is not in the list (Request, Draft Request, Supplement, Acceptance Review, Meeting, Withholding Request, Withholding Request Acceptance, RAI, Draft RAI, Draft Response to RAI, ...) of allowed values for the "Project stage" property.
| ML23272A183 | |
| Person / Time | |
|---|---|
| Issue date: | 10/17/2023 |
| From: | Sayoc E NRC/NRR/DNRL/NLIB |
| To: | Hayes M NRC/NRR/DNRL/NLIB |
| Shared Package | |
| ML23279A143 | List: |
| References | |
| Download: ML23272A183 (10) | |
Text
Enclosure 2 U.S. NUCLEAR REGULATORY COMMISSION
SUMMARY
OF THE AUGUST 21 AND 22, 2023, PUBLIC MEETINGS WITH MEMBERS OF THE PUBLIC AND INDUSTRY REPRESENTATIVES ON REVISED SUBSEQUENT LICENSE RENEWAL GUIDANCE, DRAFTS FOR COMMENT Meeting Summary On July 11, 2023, the U.S. Nuclear Regulatory Commission (NRC) published revisions to the Subsequent License Renewal (SLR) Guidance Documents, and a supplement to the associated Technical Bases Document, draft for comment, in the Federal Register (88 FR 44160), Docket ID NRC-2023-0096.
As part of NRCs outreach process, the NRC staff conducted a 60-day comment period (which was subsequently extended to 90-days), and held information public meetings on August 21 and 22, 2023, at the NRC Headquarters in Rockville, Maryland to discuss the NRCs revised SLR guidance documents.
These meetings provided an opportunity for the NRC staff to engage industry representatives and members of the public in order to provide project information, status, and an overview of proposed guidance revisions, to obtain initial feedback on proposed revisions, and to offer recommendations on how to best formulate comments to facilitate staff adjudication or resolution. No commitments were accepted for the purposes of staff adjudication, and no decisions were made during the public meeting.
2 The NRC staff presented on the project overview, process, milestones, project specifics, and notable changes to the guidance. The NRC staffs presentation slides,1,2,3 and draft NUREG reports for comment are publicly available on the Agencywide Documents Access and Management System (ADAMS)4,5,6,7 8,9.
1 U.S. NRC, SLR Guidance Update Public Meetings Slides 21-2023 Mechanical, dated August 21, 2023, Agencywide Documents Access and Management System (ADAMS) Accession No. ML23229A002, part of ML23229A001.
2 U.S. NRC, SLR Guidance Update Public Meetings Slides 22-2023 Electrical, dated August 22, 2023, ML23229A003, part of ML23229A001.
3 U.S. NRC, SLR Guidance Update Public Meetings Slides 22-2023 Structural, dated August 22, 2023, ML23229A004, part of ML23229A001.
4 U.S. NRC, NUREG-2191, Draft Report for Comment, Vol. 1, Rev. 1, "Generic Aging Lessons Learned for Subsequent License Renewal (GALL-SLR) Report", dated July 31, 2023. (ML23180A182) 5 U.S. NRC, NUREG-2191, Draft Report for Comment, Vol. 2, Rev. 1, "Generic Aging Lessons Learned for Subsequent License Renewal (GALL-SLR) Report", dated July 31, 2023. (ML23180A188) 6 U.S. NRC, NUREG-2192, Draft Report for Comment, Vol. 1, Rev. 1, Generic Aging Lessons Learned for Subsequent License Renewal (GALL-SLR) Report, dated July 31, 2023. (ML23180A191) 7 U.S. NRC, NUREG-2221, Draft Report for Comment, Technical Bases for Changes in the Subsequent License Renewal Guidance Documents, NUREG-2191, Revision 1, Draft Report for Comment and NUREG-2192, Revision 1, Draft Report for Comment, dated July 31, 2023.
(ML23180A208) 8 U.S. NRC, Subsequent License Renewal Guidance Documents, Draft Report for Comment, Track Changes Version, dated August 2, 2023. (ML23208A002) 9 U.S. NRC, NUREG-2192, Revision 1, "Standard Review Plan for Review of Subsequent License Renewal Applications for Nuclear Power Plants, Draft Report for Comment, Corrected Tables 3.1-1 and 3.2-1," dated August 4, 2023. (ML23213A036)
3 Day 1 of the public meeting began at 8:30 AM. The following summarizes discussions during the meeting:
After introductions and opening remarks, the NRC staff delivered a presentation that included background information on the SLR Guidance update project, as well as notable changes made to mechanical sections of the guidance.
The NRC staff clarified that comments submitted for review and adjudication need to be in writing, submitted via regulations.gov per the instructions of the Federal Register notice, or mailed to the NRC. Verbal comments provided at the meeting are for discussion purposes only and will not be, on their own, addressed by the NRC staff.
A commenter raised a general topic related to several Aging Management Programs (AMPs) that proposed the elimination of prescriptive follow-up inspections or actions, and instead allow a determination of required inspections by the corrective action program (CAP) based on analysis of system status, condition, and operational information. Another commenter added that plant CAPs are mature and effective, are driven by system data and conditions, and are very good at addressing any age-related degradation. The commenter added that SLR guidance prescriptive actions may divert limited station resources from valuable work, that the actions may make plant operators simply follow guidance as opposed to properly investigating and interrogating situations properly, and that they essentially shift the responsibility and burden on corrective action from the licensee to the NRC, which is inappropriate. The NRC staff recommended commenters take a holistic view of the AMP, its development, and changes within the AMP over the years. Regarding the prescriptive corrective actions, consider what was the history and the reasoning behind the prescriptive actions being added, and look at the original SLR guidance technical basis document, NUREG-2221.10 The NRC staff recommended commenters include AMP-specific detailed justifications for recommendations that addresses the AMPs history, and technical basis for the guidances prescriptive actions, along with mark-ups of the specific changes being requested.
A recommendation was discussed to eliminate the need to reassess the exclusion for wall thickness monitoring for piping systems that operate less than 2% of plant operating time.
The NRC staff pointed out that NSAC-202L11 is the Electric Power Research Institute (EPRI) guidance that provided the 2% operating time exclusion criterion. The NRC staff added that the 2% criterion has been used over time through license renewal and SLR reviews, and needs to be validated and baselined for generic application going forward.
The NRC explained that low usage systems may have special operational parameters warranting the prescribed reassessment, essentially to ensure that the 2% model is based on valid assumptions. The NRC staff recommends commenters to provide detailed information for justification for the reassessment elimination.
A recommendation was discussed that one-time Inspections for XI.M2, Water Chemistry, XI.M30, Fuel Oil Chemistry, and XI.M39, Lubricating Oil Analysis, AMPs should be eliminated because operating experience (OE) showed that age-related degradation due 10 U.S. NRC Regulation, NUREG-2221, Revision 0, Technical Bases for Changes in the Subsequent License Renewal Guidance Documents NUREG-2191 and NUREG-2192, dated December 2017.
(ML17362A126) 11 NSAC-202L-R4, Recommendations for an Effective Flow-Accelerated Corrosion Program, dated November 26, 2013, https://www.epri.com/research/products/1011838.
4 to low or stagnant flow is rare, and CAP programs across the power plant fleets address these and other degradation issues. The inspections are an administrative burden and require additional field work without tangible benefits. The NRC staff recommended that commenters provide plant-specific OE data to support their recommendation to eliminate one-time inspections that are intended to verify that degradation is not occurring, or not occurring at a rate that would prevent the component from performing an intended function.
In relation to New AMP XI.M43, High-Density Polyethylene (HDPE) Piping and Carbon Fiber Reinforced Polymer (CFRP) Repaired Piping, a comment was made that the focus of this new program is on HDPE piping that meets the requirements of American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section III, Mandatory Appendix XXVI for construction of safety Class 3 buried piping, and that HDPE piping is no longer covered under XI.M41, Buried and Underground Piping and Tanks.
The commenter added it is now unclear whether or not the GALL-SLR covers the non-safety-related or above ground HDPE piping. The NRC staff confirmed the stated AMP focus, requested the commenter to provide sufficient details in their written comment, and requested commenters to provide examples of non-safety-related applications that need clarification.
Another commenter stated that HDPE and CFRP materials are industry proven to be highly reliable and have low maintenance requirements, that most observed issues are not age-related, that certain XI.M43 AMP guidance is unnecessary as defects would be covered under CAP, and that the AMP disincentivizes the time and cost savings of using HDPE and CFRP materials. Another commenter brought up three aging management review (AMR) line items added for flow fouling or blockage of HDPE piping in a raw water environment, and that HDPE is generally not susceptible to fouling with its enhanced flow properties. A commenter added that there were also AMRs added for loss of material of HPDE piping due to exposure to temperature or moisture, and that there was no technical basis for these items given HDPEs thermal and moisture durability. The NRC staff offered that the fouling, thermal, and moisture items are designed to take into consideration the system as a whole and encouraged the commenter to submit written comments with sufficient background information, operating experience examples, plant specific data, and parameters (flow, temperature, and moisture ranges) to better facilitate disposition.
A commenter brought up that AMP XI.M43 element 3a and 3b inspections and testing are not clear in terms of intent and scope. The NRC staff acknowledged the comment and encouraged the commenter to provide the sections that need clarification.
A commenter brought up that AMP XI.M43 covers internal CFRP repairs, but some plants have done external CFRP wraps, which are not covered by this program. The commenters inquired if NRC considered aging management of these external wraps and added that this coverage could be done within the XI.M43 AMP. The NRC staff acknowledged the comment and encouraged the commenter to provide detailed recommendations and examples of applications for the proposed coverage.
A commenter recommended that Table XI.M35-1, Examinations, Item A, Note (1) Must have no history of age-related cracking, should be modified to put a limit on no history, specifically that 10 years of history should be sufficient to establish no history. This would clarify and eliminate unnecessary burden on the licensees to establish no history in
5 OE for age related cracking in Class 1 small bore piping. The NRC staff responded by saying that all plants that went through initial license renewal completed the related OE plant history search for this program, and there is no requirement to redo the search.
Licensees would only need to do supplemental searches covering from the last search to present time. Based on the OE search results, if there are no instances found for age related cracking in Class 1 small bore piping, the licensee has met the no history condition. The NRC staff cautioned that if the 10 year time limit was incorporated in the guidance, it is possible that certain time periods could be left uncovered by OE searches.
The NRC staff welcomed written comments on the matter and encouraged more details, facts, and OE for the NRC staff's consideration.
In relation to AMP XI.M41, Buried and Underground Piping and Tanks, a comment was brought up that the AMP provides a list of alternative examinations that can be performed in lieu of visual examination of piping external surfaces and coatings by excavation of buried components. One of the alternatives is to perform internal volumetric examination of at least 25% of the system for each material type to be examined. The commenter added that internal volumetric examination (when compared to external visual examination) provides more insight into the integrity of the system. It was recommended that the minimum 25% requirement be eliminated, and internal volumetric examination and external visual examination be treated equally in terms of piping examination. The commenter indicated a written comment would be submitted with reference to EPRI reports that evaluated internal volumetric examination techniques. The commenter added that another alternative in the AMP is to perform a 25% internal inspection by a method capable of measuring wall thickness but cautioned that for prestressed rebar reinforced concrete piping or metal bar wrapped concrete piping, wall thickness is not the main factor governing component integrity. Industry would be better off looking at internal surface condition and nondestructive evaluation (NDE) of rebar or wiring pipe supports. The commenter recommends that the guidance address industry standard practices for assessing concrete piping where wall thickness is not the main governing factor for component integrity.
In a separate but related comment, it was pointed out that the GALL-SLR includes recommendations for cementitious coating of buried pipes referring to National Association of Corrosion Engineers (NACE) documents, however the pipes at the plants are not typically coated per the NACE documents so there is a gap in the guidance and the related piping components at the plants. Additional comments were added that GALL-SLR references to carbonate-bicarbonate environments related to buried piping downstream of compressor stations are not applicable, as the specific environmental conditions are not experienced at the nuclear power plants. It was also recommended to remove the 10-linear foot minimum length requirement for pipe excavation visual examinations, and to allow licensees to use vacuum trucks for leak testing. Commenters indicated that written comments would be submitted on these matters. The NRC staff acknowledged and welcomed the comments and encouraged details, references, OE, data analysis, and specific recommendations that would aid in comment disposition.
Other comments on buried components relate to inspection of representative samples where new guidance unnecessarily requires samples be taken from different locations, expectations for opportunistic inspections leading to implementation issues, increased sample size of buried grey cast iron components should be limited to locations where water submergence is a concern, and the need to clarify whether or not mechanical testing of buried cast iron components is required only if an external coating is missing.
6 A comment was made on Cathodic Protection (CP) related to buried piping, that for plants that dont have CP, backfitting CP systems is burdensome with little benefit. Reasons include ineffectiveness of the CP systems where piping systems buried for over 60 years already have degradation, the soil environment may not be conducive to corrosion, and that some examinations show pipes in good condition even after being buried 60 years.
The NRC staff acknowledged the comment and recommended adding sufficient justification if not using CP, details on the CP systems, when they were installed, were they maintained and operated the whole time, if not when did it cease to operate, and what trends in pipe degradation can be related to the CP system operation.
A comment was made that for AMP XI.M33, Selective Leaching, the guidance should incorporate recent advancements in NDE techniques that have been evaluated and documented by EPRI and widely used in the nuclear and non-nuclear industries for evaluating component integrity. Allowing licensees to use the NDE techniques would add more flexibility in meeting NRC guidance.
Under AMP XI.M3, Reactor Head Closure Stud Bolting Program, a recommendation was made to eliminate the Preventive Action Element 2d, which relates to the use of bolting materials with yield strength of 150 ksi, or ultimate tensile strength of 170 ksi. In many cases the plants purchased studs prior to publication of the guidance documents.
Therefore, the studs used in plants could potentially be made of materials with yield and/or ultimate tensile strengths greater than those recommended in the guidance or could have undetermined yield and/or ultimate tensile strengths. Plants therefore are required to take exceptions in these cases even when using volumetric examinations detecting stress corrosion cracking in the studs. The recommendation would alleviate the need to take said exceptions. The NRC staff pointed out that the guidance is written to be consistent with Regulatory Guide (RG) 1.6512 and to promote the use of appropriate materials for the studs to reduce the potential for stress corrosion cracking. For the volumetric examination of reactor vessel threads and flange, there is a conditionally approved code case N-864, incorporated in RG 1.147, Revision 2013 that provides the latest guidance. The NRC staff encouraged detailed written comments for consideration.
A comment was made that in AMP XI.M27, Fire Water System, portions of the guidance are based on National Fire Protection Association standards written for general application and are not designed for, or not specifically applicable to, nuclear power plants. A recommendation was made to eliminate the nonapplicable guidance requirements that pose unnecessary burden on the licensees because they do other tests and activities that in many cases exceed the intent of the AMP. Examples of these nonapplicable tests are main drain testing for fire systems, hydraulic flow sample testing of the most remote post stations by zone, and inspection of vertical pump intake suction strainers and intake traveling screens. In addition, removing the option of air testing foam sprinkler systems was brought up, citing the problems of intentionally sprinkling foam chemicals and an unclear technical basis for the change. The recommendation is to restore this option in the guidance. The NRC staff encouraged detailed written comments for consideration.
12 U.S. NRC Regulatory Guide, RG 1.65, Materials and Inspections for Reactor Vessel Closure Studs, dated October 1973. (ML003740228) 13 U.S. NRC Regulatory Guide, RG 1.147, Revision 20, Inservice Inspection Code Case Acceptability, ASME Section XI, Division 1, dated December 17, 2021. (ML21181A222)
7 The Nuclear Energy Institute (NEI) indicated that they would be submitting formal written comments, acknowledged that the NRC staff advised commenters to include in their comments detailed supporting justification and information to help the NRC staff disposition comments, and planned to submit a formal request to extend the comment period by 30-days (to make the deadline October 11, 2023). The NEI added that their comments would relate to Revision 0 of the guidance documents, not only to the proposed changes of Revision 1.
The NRC staff indicated there would likely be a revision to the presented schedule in light of the NEI comment period extension request, and that depending on the scope of the comments (Revision 0 versus Revision 1), or the complexity of the comments, the NRC staff may not include or adjudicate all comments in this round of guidance document updates.
The NRC staff advised the commenters to be specific with the recommendations, requests, or challenges, particularly with the AMP corrective action elements. These elements have been in place for quite some time now and were not changed significantly in the current round of updates. Finally, the NRC staff requested the comments be submitted as they are completed to allow the NRC staff to review and disposition the comments as they are submitted.
Day 1 of the public meeting ended at 2:45 PM.
Day 2 of the public meeting began at 8:30 AM. The following summarizes discussions during the meeting:
After introductions and opening remarks, the NRC staff delivered a presentation similar to that of Day 1 and focused on notable changes made to electrical and structural sections of the guidance.
A comment was made in relation to the AMP XI.E1, Electrical Insulation for Electrical Cables and Connections Not Subject To 10 CFR 50.49 Environmental Qualification (EQ)
Requirements, program description and scope. The commenter added that the technical basis for the change was to include mechanical components associated with electrical equipment, however, not all plants have a mechanical EQ program, and active components have preventive maintenance to maintain their qualification (under 10 CFR 50.49). The NRC staff stated that EQ programs are given credit under time limited aging analysis to ensure that equipment qualification is addressed over the life of the equipment and to ensure that mechanical components that are important to the function of electrical equipment are not left off the scope of the AMP. The intent is not to reestablish or require a mechanical EQ program. The NRC staff welcomed any comments or recommended text to clarify the AMP.
A comment was brought up regarding the basis of adding fire barriers to the scope of the XI.E1 AMP. The NRC confirmed that the concern and the reason why fire barriers are in scope is that fire barriers that coat or insulate cables reduce cable cooling by exposure to ambient air and that the barriers make accessibility of cables impossible for visual inspection. The NRC staff welcomed any comments and recommendations on alternate places where the fire barriers could be addressed.
8 A comment was made in relation to AMP XI.E3C, Electrical Insulation for Inaccessible Low-Voltage Power Cables Not Subject To 10 CFR 50.49 Environmental Qualification Requirements, recommending the addition of specific materials used in AP1000 cables, and that thermoplastics are included but are rarely used in the nuclear industry, which favors the more common thermoset jacket materials. The NRC staff welcomed a comment with material recommendations and added that the AMP should address materials more generically and perhaps cite examples. In relation to low-voltage inaccessible cable test frequency the commenter pointed out that GALL-SLR, Revision 0 had a 10-year frequency, however, Revision 1 increased to a 6-year frequency. The commenter added that EPRI has done extensive work developing test techniques for submerged cables and collecting data between 2009-2015 and that studies have shown that there is a low probability of cable failure after being tested for satisfactory function within the first 10 years of use. Older cables do not necessarily imply higher probability or instances of degradation. Generic Letter GL 2007-0114 established the need to keep the cables as dry as possible and to monitor cable and environment conditions with testing. Given studies and years of experience, the commenter recommended the use of EPRI tests techniques and that the 10-year frequency be restored for cables that show no degradation. Another commenter proposed exceptions for newly replaced cables to extend the frequency to 10-years. The NRC staff pointed out that older plants typically replace old and degraded cables so that there is not a lot of data for cables that are buried over 50 years. The NRC staff welcomed detailed comments, to provide the EPRI reports, alternative approaches, and any other supporting information to help with adjudication and establishment of reasonable assurance.
A commenter brought up AMP XI.E5 Fuse Holders, commenting that he looked at about five LRAs/SLR applications to see if they had in-scope fuse holders and found that only one plant had eight in-scope fuse holders. The commenter added that a significant amount of work is required to figure out if fuse holders are in scope, and pointed out that given the apparent low frequency on holders that are in-scope that the AMP should be eliminated. The NRC staff stated that XI.E5 is consistent with the guidance in LR-ISG-515 and the requirements specified in 10 CFR 54.4(a), and that fuse holders should be scoped, screened, and included in the AMR in the same manner as terminal blocks and other types of electrical connections. The NRC staff acknowledged that they have not seen a lot of fuse holders being scoped in but that the aging management of these holders is still important and given that there are only a handful of initial license renewal plants left it would make sense to run the course and keep the program in place.
On AMP XI.S6, Structures Monitoring, a comment on element 4. Detection of Aging Effects, related to structures that are in scope for 10 CFR 54.4(a)(2) indicated that monitoring at a 5-year frequency is excessive and that a 10-year frequency is more appropriate. The reason is that for structures whose sole function is not to collapse and affect the function of safety systems, this lower frequency is more appropriate. The NRC staff pointed out that during the development of this AMP the NRC staff publicized their 14 U.S. NRC Generic Letter 2007-01, November 8, 2012, Inaccessible or Underground Power Cable Failures That Disable Accident Mitigation Systems or Cause Plant Transients: Summary Report, dated November 8, 2012. (ML082760385) 15 U.S. NRC Interim Staff Guidance, LR-ISG-5, Identification and Treatment of Electrical Fuse Holders for License Renewal, dated June 8, 2005. (ML030690492)
9 proposals on the inspection frequencies, which were based on American Concrete Institute report ACI 349.3,16 and that adjudication of inspection frequencies involved the industry. Nevertheless, the NRC staff welcomes any written comments on this matter with specific details on what has changed driving the less frequent inspections and any supporting justification or information.
A general comment was made that the opportunistic inspection required in several AMPs (such as Structures Monitoring) often leads to unnecessary administrative burdens, diversion of already limited resources, technical and logistical challenges, and it was recommended that whenever possible the opportunistic inspection be replaced with discrete inspections. This way licensees can better plan, execute, and analyze said inspections.
A comment was made that unlike AMP, XI.S8, Protective Coating Monitoring and Maintenance, which references the latest RG 1.54, Revision 3,17 several other AMPs reference earlier revisions of said RG. The recommendation was to make all AMPs consistent in reference to the latest RG revision, and a written comment on the matter will be submitted to the NRC staff.
The NRC staff provided a summary of the new SRP-SLR further evaluation (FE)
Section 3.5.2.2.2.8, Combined Effects of Aging Associated with Irradiation of Reactor Vessel (RV) Steel Structural Support Components and Loss of Function of Other RV Structural Support Components That are Not Concrete, and three new AMR items (two for visual exams and one for volumetric exam with evidence of combined aging effects). A comment was made that the fluence threshold in the FE seems low compared to the thresholds provided in NUREG-1509.18 It was noted that there are groupings of reference materials by specification provided in NUREG-1509 and that nondestructive test (NDT) is prescribed to determine that the materials being applied are representative of the NUREGs reference materials. However, the FE requires additional justification for concluding the materials are representative, but it is unclear what additional information is requested, and the commenter recommended clarification on the guidance. On embrittlement predictions the guidance takes into consideration material chemical composition. The commenter indicated that since the materials cited are irradiated at low temperature, chemistry isnt really a factor, and recommended elimination of chemical composition consideration from the guidance. The NRC staff acknowledged the comment, pointed out that the guidance was written to be intentionally broad to accommodate a wide range of materials and applications, and encouraged formal written comments be submitted with recommendations and supporting information.
A commenter cautioned that the FEs recommended initial inspections prior to analysis would likely have technical challenges with licensees. The NRC staff pointed out that inspections conducted from other AMPs (such as the Structures Monitoring or ASME 16 American Concrete Institute, ACI PRC-349.3-18: Report on Evaluation and Repair of Existing Nuclear Safety-Related Concrete Structures, https://www.concrete.org/Portals/0/Files/PDF/Previews/349.3R-18_preview.pdf.
17 U.S. NRC, Regulatory Guide, RG 1.54, Revision 3, Service Level I, II, III, and In-Scope License Renewal Protective Coatings Applied to Nuclear Power Plants, dated April 2017. (ML17031A288.)
18 U.S. NRC Regulation NUREG-1509, Radiation Effects on Reactor Vessel Supports, dated May 1996. (ML22143A839)
10 Section XI, Subsection IWF) can be used to fulfill this requirement and that the NRC staff does not intend to impose new inspections.
A commenter stated that embrittlement would be difficult to assess with the prescribed visual inspection followed by volumetric inspection. The NRC staff offered that embrittlement can be manifested through phenomenon that is detectable, such as cracking or distortion as a result of cracking, that NUREG-1509 gives the option to screen out materials, that the FE guidance was developed based on NUREG-1509, and recommended licensees look at how the NRC staff dispositioned these topics in the previous seven SLRAs. Applications have varied some, requiring slightly different approaches, but there are general themes that can be drawn from previous reviews.
Closing remarks by the NRC staff emphasized the importance of industry and public participation and comments on the guidance update process and provided a summary of schedule milestones going forward. NEI acknowledged the underlying message from the NRC staff which was that they welcomed comments in all matters discussed and that written comments should consider the background and technical bases for the guidance, and should include detailed justification, recommendations, mark-ups, supporting data, system parameters, references, or documents, which all lend to a more effective and efficient disposition of comments by the NRC staff.