ASME STP-NU-057-2013 pdf download

ASME STP-NU-057-2013 pdf download.ASME CODE DEVELOPMENT ROADMAP FOR HDPE PIPE IN NUCLEAR SERVICE.
3 IDENTIFIED R&D PROGRAMS
The survey was successful in identifying solutions to many of the issues. Many solutions arc currently in place or under development, such as the ongoing research by the Electric Power Research Institute (EPRI). Others are awaiting implementation. and are in need of research funds, such as the program outlined in a white paper jointly Tittcn by the Gas Technology Institute (GTI) and the National Institute of Standards and Technology (NIST), entitled “Improving the Performance of Service Watcr Piping in Nuclear Power Plants.” Other rcscarch firms, individual researchers affiliated with testing laboratories or universities and resin manufacturers proposed solutions through testing or dcvcloping tests through experiments. These will be discussed in the Action Plan later in this Roadinap.
3.1 Work In Progress
The roadmap suncy revealed several issues of importance to the piping applications. They are related to codes and standards, quality and performance and testing and evaluation. A few of these
arc:
CC N-755-l: Split the needs and requirements of ASME Section III and Section Xl so each Section will have its own Code Case.
• U.S. and International Standards: Identify U.S. and international standards and modify where needed to reflect the requirements of HDPE in nuclear application. (Aaron Forstcr, Leader).
• Define and specify design and acceptance criteria, and allowable essential parameters.
• Develop new, and optimize existing, test methods and procedures which deal with piping lifetime performance and prediction, bascd on models and’or experiments.
The aforementioned issues will be further discussed later in this document.
3.2 Schedule and Key Milestones [4J
• The Roadmap Strategies arc to be executed in a timely manner.
• An events schedule with key milestones will be displayed by a Gantt chart.
• A justification of the cvcnts schedule with key milestones will be represented in tabulated form.
• The Roadmap will be a living document and must have a flexible approach to adapt to future considerations.
• Events schedule will include frequent peer rcvicvs by all stakcholders to ensure acceptance of the final results.
• A process for resolving conflicts that arise during peer review will be provided.
3.3 Technology Development and Deployment
3.3.1 Short-term Deployment
• Has a tiincframc of 0-5 years.
• Concerned with existing gaps and technology and immediate needs, these are:
o Develop and support acceptance criteria for volumetric flaws.
5 FUSED JOINTS INTEGRITY
Pipe fusion consists of prepping the interface of pipe-ends by resurfacing and cleaning them; bringing them against a hot plate for a predetermine hold-time at specific pressure and temperature. Once the hot plate is removed, the two pipe-ends are pushed against each other and held in place for a predetermined time to create intimate fusion. To safeguard the integrity of fused joints, the following concerns must bc addrcsscd and resolved:
• Develop procedures to qualify fusion equipment and operators (covered in ASME BVPC Section IX).
• Determine which fusion parameters must be monitored and recorded (covered in ASME BVPC Section IX).
• Consult the Plastics Pipe Institute’s (PPI) Technical Report 161 on pipe fusion to derive usefulness and gaps in the report.
Other issues which require the industry’s dedication arc the certitude of the integrity of short- term and long-term performance of the fused joints, including fittings and flanges under adverse conditions. These conditions include:
• Exposure to chemicals
• Radiation
• Excursion in temperature/heat and pressure
• Vibrationlcarthquake
• Oxidation
• Any combination of two or more of the above.
Fused large diameter (>36” OD) and thick wall pipes (>3.5”) have not received as much attention in research and performance evaluation as smaller pipes. Fusion procedure, inspection and long-term performance requirements must demonstrate the integrity and repeatability of the process to satisfy regulators and power plant owners.
Strong emphasis has been devoted to cold fusion and voids. These flaws may or may not be a detriment to the fusion integrity if they exist in a small percentage of the total fused area. Voids may or may not be avoidable or detectable; therefore, research must be conducted to determine and define allowable flaws and ironically their potential benefits. Small voids arc theorized to arrest the propagation of a crack should they happen to be in its path.
Based on the responses to the survey, the following issues must be addressed and resolved to instill confidence in the fusion process and intcgrity:
• Evaluate the short-term and long-term performance of joints of pipes, valves, fittings and flanges under adverse conditions and transient behavior such as stress, chemicals/chlorine, cold fusion, vibration/earthquake, oxidation, fire/heat excursions.
• Develop short-term fusion integrity test methods which correlate with long-term standard method.
• Develop a model to evaluate the effect of fusion variables on thcrmo-rhcological characteristics of PE 4710 during the fusion process.