ML21313A256
| ML21313A256 | |
| Person / Time | |
|---|---|
| Issue date: | 11/16/2021 |
| From: | Steve Jones Office of Nuclear Reactor Regulation |
| To: | |
| SJG1 | |
| References | |
| DG-1381, RG-1.244 | |
| Download: ML21313A256 (11) | |
Text
Draft Regulatory Guide 1.244 Control of Heavy Loads at Nuclear Facilities Steven Jones, Acting Chief Containment and Plant Systems Branch, NRR Presentation to the Advisory Committee on Reactor Safety, Subcommittee on Regulatory Policies and Practices November 16, 2021
Agenda
- 1. Introduction
- 2. Existing Guidance
- 3. Proposed New Guidance
- 4. Safety Significance
- 5. Response to Public Comments
- 6. Conclusion
Introduction
- Purpose of RG 1.244:
- Endorse appropriate consensus standards for control of heavy loads
- Update guidance contained in current technical reports
- Expand applicability to include lifting devices used for major component replacement and spent fuel storage
- These consensus standards provide updated guidance for heavy load handling programs, including:
- methods to assure safety functions are accomplished considering equipment failures and effects of natural phenomena
- standards for operation, maintenance, and testing of handling systems, especially enhanced reliability systems
Existing NRC Guidance
- NUREG-0612, Control of Heavy Loads at Nuclear Power Plants
- Provides criteria for protection of safety functions
- Specifies good practices for the handling of heavy loads
- NUREG-0554, Single Failure-Proof Cranes for Nuclear Power Plants
- Provides criteria for crane design, fabrication, and testing
- Specifies features to control load following component failures, natural phenomena, and operator errors
- ANSI N14.6, Radioactive MaterialsSpecial Lifting Devices for Shipping Containers Weighing 10 000 Pounds (4500 kg) or More for Nuclear Materials
- Provides criteria for lifting device design and testing
- Specifies inspection and testing to verify continued compliance
Proposed Endorsed Standards
- American Society of Mechanical Engineers (ASME) Standard NML-1-2019, Rules for the Movement of Loads Using Overhead Handling Equipment in Nuclear Facilities
- Replacement for NUREG-0612
- Qualitative risk-informed approach
- Scope expanded for wider use at nuclear facilities
- Updated to reflect operating experience
- Restrictions on use of slings
- Simplified testing for special lifting devices
Proposed Endorsed Standards (cont.)
- ASME Std. NOG-1-2020, Rules for Construction of Overhead and Gantry Cranes (Top Running Bridge, Multiple Girder)
- Replacement for NUREG-0554
- Reflects current technologies
- ASME Std. BTH-1-2017, Design of Below-the-Hook Lifting Devices, Chapters 1-3 (mechanical devices)
- Provides criteria for the design and fabrication of special lifting devices and load lifting attachments
- NML-1 and BTH-1 combined address scope of ANSI N14.6
Effect of New Guidance The staff expects endorsement of these three industry consensus standards to provide safety and efficiency benefits.
- Incorporates lessons from several decades of operating experience Administratively restricts sling usage to straight connections to specially designed attachment points or basket configurations around large diameter rounded objects for safety-significant lifts Reduces design margin and burden of testing special lifting devices based on high reliability Wire rope cranes take advantage of new designs to eliminate risk from two-blocking and provide controlled lowering systems
- Standardization of programs and training Many lifts conducted by contracted personnel during refueling outages Adds riggers to scope of training included in program to reduce risk of below-the-hook errors Flexible guidance included for special conditions
- Large component replacement (e.g., Steam Generator Replacement)
- Space/structural limitations preclude NOG-1 crane
- Outside nuclear power plant structures (e.g., ISFSI Operations)
Safety Significance
- Standard nuclear overhead handling systems provide reliable performance
- Less than one uncontrolled motion per 10,000 lifts based on operating experience
- Suitable when safety function would not be challenged by handling system failure
- NML-1 provides acceptable controls for standard and special lifts
- Enhanced safety handling systems
- Reduce frequency of uncontrolled motion by 1 to 2 orders of magnitude
- Suitable for NML-1 Nuclear Safety Critical Lifts when using crane designed to NOG-1, Type I criteria and appropriate lifting devices
Public Comment
- Availability of Draft Guide 1381 for public comment published in Federal Register on May 4, 2021
- Public comment period ended on July 5, 2021
- Nuclear Energy Institute provided 24 comments:
- 11 related to clarification of specific items
- 5 related to licensing basis change control process
- 4 related to endorsement of additional standards
- 4 related to enhance flexibility through credit for administrative controls or alternative design elements
- Two individuals provided additional comments that overlapped with NEI comments.
Changes to Draft Guide
- Background
- ANSI-N14.6 and ASME BTH-1 relationship
- Clarified that controlled ranges of motion and enhanced safety handling systems constitute complete acceptable methods of evaluation
- Explained basis for sling restrictions during critical lifts
- Regulatory guidance
- Seismic qualification of cranes used for nuclear safety critical lifts with controlled range of motion
- Clarified criteria for alternative crane designs for critical lifts
- Clarification of sling restrictions for critical lifts
Conclusion
- The staff is endorsing three industry standards
- The staff expects the revised guidance to provide safety and efficiency benefits
- The staff expects substantial adoption of NML-1 control of heavy loads program guidance through the provisions of licensing basis change control regulations