ASME Code guidelines

FAVOR software was recently employed to define licensing criteria (NRC 2010b) and ASME code guidelines (ASME, 2010) for RPV integrity the description of the PFM methodology in this chapter is based on the methodology in the FAVOR software. 

This section presents some example calculations and results from licensing criteria and ASME Code guidelines that have been developed using risk-based safety goals and probabilistic fracture mechanics computational... 

A standard is a set of technical definitions and guidelines for designers and manufacturers. A code is a standard that has been adopted by one or more governmental bodies or has been incorporated into a business contract. ASME publishes its standards accredits users of standards to ensure that they are capable of manufacturing products that meet those standards and provides stamps that accredited manufacturers place on their products to indicate that a product was manufactured according to the ASME code. 

The following are only guidelines based on Section VIII, Division 1 of the ASME Code [1]. This is not an attempt to cover eveiy possibility nor is it to become a substitute for using the Code. 

Current practice in the USA is to use the guidelines in NRC (1988) to define the adjusted reference temperature as ART = initial RT+ARTndt + margin. In this instance, a margin term is added to account for uncertainty in initial RT and ARTndt and obtain conservative upper bound values of the adjusted reference temperature.The conventional P-riimit curve that includes both the ASME Code margin of 2 on pressure and the adjusted reference defined in the regulatory guidelines (NRC, 1988) is expressed as ... 

Reactor internals design fabrication and installation are covered by rules given in Section in of the ASME Boiler and Pressure Vessel Code, Subsection NG, Core Support Structures. Core support structures are those structures or parts of structures, which are designed to provide direct support or restraint of the core, within the reactor pressure vessel. Before Subsection NG was published. Subsection NB of the ASME Code was used as a guideline for the development of vendor-specific internals system design criteria. The rules for reactor internals design are covered in Article NG-3000. 

Some system uses one pressure relief device for overpressure protection, but some uses more than one. Some relief contingency is non-fire, but some is caused by fire. ASME Section VIII (ASME code) has some guideline for PRD set pressure and accumulated pressure for different cases, see Table 1. 

Eddy current examination of austenitic stainless steel pipe and tubing shall follow the general guidelines of ASME BPV Code Section V, Article 8, subject to the following specific requirements for pipe and tube ... 

The world of codes and standards is an absolute labyrinth, so the emphasis here will be only on the main issues from ASME and PED, which cover about 80% of all worldwide requirements. The exceptions are China and India, who follow their own guidelines, although they are mostly focused on boiler applications. Also, we will concentrate on the industrial process applications and only refer to these applicable codes. 

Appropriate codes for new tank construction include ASME Section VIII Pressure Vessel Code, API 650 for Atmospheric Tanks, API 620 for Low-Pressure Storage Tanks. Appropriate codes for other aspects include ANSI/ASME B31.3 Code for Pressure Piping, the National Fire Protection Association Codes, Tubular Exchanger Manufacturers Association standards, property insurance guidelines, and any local or federal requirements. 

In the European Union, the design, manufacture, and use of pressure systems is covered by the Pressure Equipment Directive (Council Directive 97/23/EC) whose use became mandatory in May 2002. European standard EN 13445 provides similar rules and guidelines to the ASME BPV Code. The design of fiber-reinforced plastic vessels is covered by European standard EN 13923. 

The System 80+ Standard Design, steam generators, and reactor coolant system are protected from overpressurization in accordance with the guidelines set forth in the ASME Boiler and Pressure Vessel Code, Section III. Peak reactor coolant system and secondary system pressures are limited to 110% of design pressures during a worst case loss load event. Overpressure protection is afforded by primary safety valves, secondary safety valves, and the Reactor Protection System. 

Pressure vessel design, construction, and inspection is referenced in the ASME Boiler and Pressure Vessel Code, 1968, and current 1910.106(b), 1910.217(b)(12), 1910.261(a)(3), and OSHA Technical Manual CPL 2-2.208, Chapter 10 (Pressure Vessel Guidelines). These set the guidelines for pressure vessel safety. Two consequences result from a complete rupture (1) blast effects can happen due to a sudden expansion of the pressurized fluid, and (2) fragmentation damage and injury can result if vessel rupture occurs. 

Hechmer and Hollinger have proposed ten guidelines on the evaluation of stresses in pressure vessels calculated by finite-element method in the spirit of the ASME Boiler and Pressure Vessel Code. ... 

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