Requirements of Part 50 Appendices

Appendix A — General Design Criteria for Nuclear Power Plants

Under the provisions of Subsection 50.34, an application for a construction permit is required to include the principal design criteria for a proposed facility. The principal design criteria establish the necessary design, fabrication, construction, testing, and performance requirements for SSCs important to safety; that is, to ensure that the performance of the SSCs will provide reasonable assurance that the facility can be operated without undue risk to the health and safety of the public.

These General Design Criteria establish minimum requirements for the design, construction, inspection, preoperational testing, periodic inspection and testing of the water-cooled nuclear power plant SSCs similar in design and location of plants for which construction permits have been issued by the Commission. The General Design Criteria are also considered to be generally applicable to other types of nuclear power reactors (e.g., High Temperature Gas Cooled Reactors — HTGRs) and are intended to provide guidance in establishing the principal design criteria for such other reactors.

Readers should note that the development of these General Design Criteria is not yet complete. For example, some of the definitions need further amplification. Also, some of the specific design requirements for the SSCs important to safety have not as yet been suitably defined. Their omission does not relieve any applicant from considering these matters in the design of a specific facility and satisfying the necessary safety requirements. Such matters include:

  • • Consideration of the need to design against single failures of passive components in fluid systems important to safety;
  • • Consideration of redundancy and diversity requirements for fluid systems important to safety.

A system could consist of a number of subsystems each of which is separately capable of performing the specified system safety function. The minimum acceptable redundancy and diversity of subsystems and components within a subsystem, and the required interconnection and independence of the subsystems have not yet been developed or defined;

  • • Consideration of the type, size, and orientation of possible breaks in components of the reactor coolant pressure boundary in determining design requirements to suitably protect against postulated loss-of-coolant accidents;
  • • Consideration of the possibility of systematic, non-random, concurrent failures of redundant elements in the design of protection systems and reactivity control systems.

It is expected that the criteria will be augmented and changed from time to time as important new requirements for these and other features are developed.

There will be some water-cooled nuclear power plants for which the General Design Criteria may not be sufficient, and for which additional criteria must be identified and satisfied in the interest of public safety. In particular, it is expected that additional or different criteria will be needed to take into account unusual sites and environmental conditions, and for water-cooled nuclear power units of advanced design. Also, there may be water-cooled nuclear power units for which fulfillment of some of the General Design Criteria may not be necessary or appropriate. For plants such as these, departures from the General Design Criteria need to be identified and justified.

Appendix B — Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plants

Every applicant for a construction permit is required by the provisions of Subsection 50.34 to include in its PSAR a description of the quality assurance program to be applied to the design, fabrication, construction, and testing of the structures, systems, and components of the facility. Every applicant for an operating license is required to include, in its FSAR, information pertaining to the managerial and administrative controls to be used to assure safe operation.

The pertinent requirements of this appendix apply to all activities affecting the safety-related functions of those structures, systems, and components. These activities include designing, purchasing, fabricating, handling, shipping, storing, cleaning, erecting, installing, inspecting, testing, operating, maintaining, repairing, refueling, and modifying.

As used in this appendix, “quality assurance” comprises all those planned and systematic actions necessary to provide adequate confidence that a structure, system, or component will perform satisfactorily in service. Quality assurance includes quality control, which comprises those quality assurance actions related to the physical characteristics of a material, structure, component, or system which provide a means to control the quality of the material, structure, component, or system to predetermined requirements.

The essential elements of the quality assurance program are briefly described here for ready reference. [1]

  • • Control of Purchased Material, Equipment, and Services — Measures shall be established to assure that the purchased material, equipment, and services, whether purchased directly or through contractors and subcontractors, conform to the procurement documents.
  • • Identification and Control of Materials, Parts, and Components — Measures shall be established for the identification and control of materials, parts, and components, including partially fabricated assemblies. These measures shall assure that identification of the item is maintained by heat number, part number, serial number, or other appropriate means, either on the item or on records traceable to the item, as required throughout fabrication, erection, installation, and use of the item.
  • • Inspection — A program for inspection of activities affecting quality shall be established and executed by or for the organization performing the activity to verify conformance with the documented instructions, procedures, and drawings for accomplishing the activity.
  • • Test Control — A test program shall be established to assure that all testing required to demonstrate that structures, systems, and components will perform satisfactorily in service is identified and performed in accordance with written test procedures which incorporate the requirements and acceptance limits contained in applicable design documents.
  • • Corrective Action — Measures shall be established to assure that conditions adverse to quality, such as failures, malfunctions, deficiencies, deviations, defective material and equipment, and nonconformance are promptly identified and corrected. In the case of significant conditions adverse to quality, the measures shall assure that the cause of the condition is determined and corrective action taken to preclude repetition.
  • • Quality Assurance Records — Sufficient records shall be maintained to furnish evidence of activities affecting quality. The records shall include at least the following: Operating logs and the results of reviews, inspections, tests, audits, monitoring of work performance, and materials analyses.
  • • Audits — A comprehensive system of planned and periodic audits shall be carried out to verify compliance with all aspects of the quality assurance program and to determine the effectiveness of the program.

The expanded version of the quality assurance requirements has been published by the ASME as NQA-1 (2008) [11] and its Addenda NQA-1a (2009) [12]. They are considered as complying with the requirements of 10 CFR Part 50 Appendix B, to the extent they are endorsed in RG 1.28 (2010) [13].

Appendix E — Emergency Planning and Preparedness for Production and Utilization Facilities

This appendix establishes minimum requirements for emergency plans for use in attaining an acceptable state of emergency preparedness. These plans shall be described generally in the PSAR for a construction permit and submitted as part of the FSAR for an operating license. These plans, or major features thereof, may be submitted as part of the site safety analysis report for an early site permit.

Appendix G — Fracture Toughness Requirements

This appendix specifies fracture toughness requirements for ferritic materials of pressure-retaining components of the reactor coolant pressure boundary of light water nuclear power reactors to provide adequate margins of safety during any condition of normal operation, including anticipated operational occurrences and system hydrostatic tests, to which the pressure boundary may be subjected over its service lifetime. The requirements of this appendix apply to the following materials:

• Carbon and low-alloy ferritic steel plate, forgings, castings, and pipe with specified minimum yield strengths not over 345 MPa (50,000 psi), and to those with specified minimum yield strengths greater than 345 Mpa (50,000 psi) but not over 621 MPa (90,000 psi) if qualified by using methods equivalent to those described in paragraph G-2110 of Appendix G of

Section XI of the latest edition and addenda of the ASME Code incorporated by reference into Subsection 50.55a (b) (2).

  • • Welds and weld heat-affected zones in the materials specified in the bullet above.
  • • Materials for bolting and other types of fasteners with specified minimum yield strengths not over 896 Mpa (130,000 psi).

The definitions of various technical terms such as ferritic material, the required fracture toughness tests, and requirements related to the fracture toughness of reactor pressure vessel are provided in this regulation.

Appendix H — Reactor Vessel Material Surveillance Program Requirements

This regulation describes the material surveillance program to monitor changes in the fracture toughness properties of ferritic materials in the reactor vessel beltline region of light water nuclear power reactors which result from exposure of these materials to neutron irradiation and the thermal environment. Under the program, fracture toughness test data are obtained from material specimens exposed in surveillance capsules, which are withdrawn periodically from the reactor vessel.

Appendix J to Part 50 — Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors

Under this regulation, the licensees of all operating light water cooled reactors are required to perform integrated and local leak rate testing of their primary containment structures and of the systems and components penetrating through the containment structures. The test requirements provide for preoperational and periodic verification of the leak-tight integrity of these components. The purpose of the tests are to assure that (a) leakage through the primary reactor containment and systems and components penetrating primary containment shall not exceed allowable leakage rate values as specified in the technical specifications or associated bases; and (b) periodic surveillance of reactor containment penetrations and isolation valves is performed so that proper maintenance and repairs are made during the service life of the containment, and of the systems and components penetrating primary containment. These test requirements may also be used for guidance in establishing appropriate containment leakage test requirements in technical specifications or associated bases for other types of nuclear power reactors. These performance criteria are the essential attributes of the containment structures, penetrating pipes, access provisions, and isolation systems; and they are discussed in detail in Chapter 4 of the book.

Appendix S — Earthquake Engineering Criteria for Nuclear Power Plants

This appendix applies to applicants for a construction permit or operating license under Part 50 (10 CFR Part 50), or a design certification, combined license, design approval, or manufacturing license under Part 52 (10 CFR Part 52) of this chapter based on the applicability criteria defined in the regulation. These criteria implement General Design Criterion 2 to the extent the criterion requires structures, systems, and components important to safety to withstand the effects of earthquakes.

  • [1] Organization — The applicant shall be responsible for the establishment and execution of thequality assurance program. • Quality Assurance Program — The applicant shall establish at the earliest practicable time,consistent with the schedule for accomplishing the activities, a quality assurance programwhich complies with the requirements of this appendix. • Design Control — Measures shall be established for the identification and control of design interfaces and for coordination among participating design organizations. These measures shall include the establishment of procedures among participating design organizationsfor the review, approval, release, distribution, and revision of documents involving designinterfaces. • Procurement Document Control — Measures shall be established to assure that applicableregulatory requirements, design bases, and other requirements which are necessary to assureadequate quality are suitably included or referenced in the documents for procurement ofmaterial, equipment, and services, whether purchased by the applicant or by its contractorsor subcontractors. • Instrumentation, Procedures, and Drawing — Activities affecting quality shall be prescribedby documented instructions, procedures, or drawings, of a type appropriate to the circumstances and shall be accomplished in accordance with these instructions, procedures, ordrawings. • Document Control — Measures shall be established to control the issuance of documents,such as instructions, procedures, and drawings, including changes thereto, which prescribeall activities affecting quality.
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