NRC Regulatory Issue Summary 2002-03 Guidance on the Content of Measurement Uncertainty Recapture Power Uprate Applications

January 31, 2002


All holders of operating licenses for nuclear power reactors, except those that have permanently ceased operations and have certified that fuel has been permanently removed from the reactor vessel.


The U.S. Nuclear Regulatory Commission (NRC) is issuing this regulatory issue summary (RIS) to provide guidance to addressees on the scope and detail of the information that should be provided to NRC for reviewing measurement uncertainty recapture power uprate applications. This RIS does not transmit any new requirements, and does not require any specific action or written response.

Background Information

Measurement uncertainty recapture power uprate applications request that the NRC amend the operating license for a plant to increase core thermal power by a value less than 2 percent of the licensed power level. Licensees typically achieve such uprates by implementing enhanced techniques for calculating reactor power. This involves the use of state-of-the-art devices that reduce the degree of uncertainty associated with measuring feedwater flow and, in turn, allow for more accurate power calculations.

The June 1, 2000, rulemaking regarding Appendix K to Part 50 of Title 10 of the Code of Federal Regulations (10 CFR Part 50) allowed licensees to use a power uncertainty of less than 2 percent in loss-of-coolant accident analyses. In so doing, the rulemaking facilitated the staff's reviews of these power uprate applications. When not accompanied by other requests or changes, applications for power uprates that are based on improved feedwater measurement techniques should have a limited effect on plant analyses and equipment. When licensees submit applications for this type of power uprate, the staff intends to focus its review on the affected areas. (For purposes of this guidance, "affected areas" are those areas for which existing analyses of record do not bound plant operation at the proposed power level and, as a result, new analyses or evaluations should be performed to provide a basis for operation at the proposed power level. Similarly, "affected equipment" includes equipment for which existing analyses of record for capacities and/or design, actual design, and/or operational or licensing functional requirements should be modified to support operation at the proposed power level.)

The NRC staff has typically completed its review of measurement uncertainty recapture power uprate applications in 6 to 8 months. The duration of the staff's review strongly depends on the quality and completeness of licensees' applications and the staff's needs for additional information. The duration of staff reviews of quality applications for which the staff does not need additional information in order to complete its review could be reduced by 2 to 3 months. These time estimates are for applications that reflect the use of approved flow measurement devices and do not include other requests or changes. If a power uprate application includes other requests or changes, the staff will apply the agency's existing timeliness goals for completing its review of the application (i.e. completing reviews of 95 percent of licensing applications within 1 year and 100 percent within 2 years.)

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Issue Summary

When licensees submit measurement uncertainty recapture power uprate applications, the staff intends to use the following general approach for their review:

  • In areas (e.g., accident/transient analyses, components, systems) for which the existing analyses of record do not bound the plant operation at the proposed uprated power level, the staff will conduct a detailed review.
  • In areas (e.g., accident/transient analyses, components, systems) for which the existing analyses of record do bound plant operation at the proposed uprated power level, the staff will not conduct a detailed review.
  • In areas that are amenable to generic disposition, the staff will utilize such dispositions.

In order to improve the efficiency of the staff's review, it is important for licensees to explicitly identify the areas that are-- and are not – affected by the power uprate. To aid licensees in optimizing their measurement uncertainty recapture power uprate applications for staff review, the staff developed the guidance in Attachment 1 to this RIS. This guidance was previously issued in draft form via a meeting notice dated August 3, 2001 (Accession Number ML012140203 in the NRC's Agencywide Documents Access and Management System, ADAMS).

On August 23, 2001, the NRC held a public workshop to discuss the draft guidance. The staff evaluated feedback received during the workshop and modified the draft guidance based on this staff evaluation. Attachment 2 to this RIS summarizes the staff's evaluation of the feedback. Attachment 2 is organized by guidance section. This organization was utilized to simplify the use (cross-referencing) of the guidance. Licensees may wish to use Attachments 1 and 2 together to ensure that they clearly understand the staff's intent in the guidance.

For further guidance on the level of detail necessary for the staff's review, licensees may refer to the corresponding sections in NUREG-0800, "Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants," the NRC's Standard Review Plan (SRP). The reference to the SRP was not intended to indicate that the SRP will be used in place of plant-specific licensing bases to assess the acceptability of an application. The SRP is referenced here solely to provide guidance regarding an appropriate level of detail; it is not intended that licensees need to conform to the guidance in the SRP. Applicability of the SRP to a plant is determined on a plant-specific basis, consistent with the licensing basis of the plant. In addition, where the NRC has approved a specific methodology (e.g., topical report) for the type of measurement uncertainty recapture power uprate being requested, licensees should follow the format prescribed for that specific methodology and provide the information called for in that methodology and the NRC's letter and safety evaluation approving the methodology.

The staff will update the attached guidance as necessary to reflect lessons learned from staff reviews. The staff may use the NRC's Web site to post updates and other information related to power uprates. Licensees are encouraged to notify the staff of areas where they believe efficiencies may be gained (e.g., areas where generic dispositions are possible).

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Backfit Discussion

This RIS provides guidance on the scope of information and level of detail that licensees should provide in measurement uncertainty recapture power uprate applications to facilitate staff review. This guidance is predicated on the experience gained from recent staff reviews of these applications. The guidance provided in this RIS does not impose new or modified staff requirements. In addition, this RIS neither uniquely prescribes a way to comply with the regulations nor requires any action or written response. Therefore, this RIS does not constitute a backfit under 10 CFR 50.109 and the staff did not perform a backfit analysis.

Federal Register Notification

A notice of opportunity for public comment was not published in the Federal Register because this RIS is informational and does not represent a departure from current regulatory requirements and practice.

Paperwork Reduction Act Statement

This RIS does not request any information collection.

If you have any question concerning this matter, please contact the person listed below.

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William D. Beckner, Program Director
Operating Reactor Improvements Program
Division of Regulatory Improvement Programs
Office of Nuclear Reactor Regulation

Technical contact: Mohammed A. Shuaibi, NRR
(301) 415-2859
  1. Guidance on the Content of Measurement Uncertainty Recapture Power Uprate Applications
  2. Evaluation of Feedback Received During the Public Workshop on August 23, 2001 (Arranged by Guidance Section)
  3. List of Recently Issued NRC Regulatory Issue Summaries

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Page Last Reviewed/Updated Wednesday, March 24, 2021