IAEA Coordinated Research Projects (CRP)

Qualification, Condition Monitoring, and Management of Aging of Low Voltage Cables in Nuclear Power Plants


Brief Summary

This CRP is intended to benefit the current generation of nuclear power plants especially those seeking License Renewals, advanced reactors, and new designs. The CRP is to cover accelerated pre-aging of cables followed by qualification testing, monitoring the performance of cable insulation material and conductors, environmental monitoring to verify ongoing qualification, and development of a testing program and maintenance schedules for cables that are important for safe operation of NPPs. Both conventional and advanced qualification and condition monitoring techniques will be covered for the most common cable types such as cross-linked polyethylene (XLPE), ethylene propylene rubber (EPR), silicone rubber (SiR), and even poly-vinyl chloride (PVC). It is understood that SiR and PVC are no longer good choices in nuclear facilities yet they are included here as these cables are still in operation in nuclear facilities in many member states. PVC materials produce corrosive by-products in the event of a cable fire and SiR are mechanically weak but can withstand high temperature environments.


Background

Cable aging and the need for condition monitoring is one of the most important aspects of plant life extension when it comes to I&C Systems. Cables, especially their insulation and jacket material are vulnerable to aging degradation during normal operation and means must be established to ensure that cable aging does not lead to unsafe operation. Cable fires, moisture intrusion, loss of functionality, and noise/interference in reading of process parameters are examples of cable issues giving rise to current and future concerns about long-term performance of cables in nuclear facilities. In fact, almost all organisations involved with the current and next generation of nuclear power plants have recognized the importance of cable qualification, condition monitoring, and aging management. As a result, substantial research has been conducted by cable manufacturers, reactor vendors, laboratories, and standards writing organisations (e.g., International Electrotechnical Commission or IEC) to understand the effect of aging on cables and to establish effective and reliable means for cable qualification and condition monitoring. In particular, the Electric Power Research Institute (EPRI), the U.S. Nuclear Regulatory Commission (NRC), Halden Reactor Project (HRP), the IEC and the International Atomic Energy Agency (IAEA) have spent substantial effort in the last two decades to address cable qualification and aging as well as cable condition monitoring. For example, the IAEA initiated the development of TECDOC 1188 in the mid-1990s to address cable aging and cable condition monitoring. This document was recently updated and a new draft is to be issued by the IAEA in early 2011. The new report, NP-T-3.6, contains the state of the art in cable qualification, condition monitoring, and aging management. Furthermore, the IEC has published a new standard (IEC 62465) on cable testing and is currently finishing a new series of standards (IEC 62582) to address specific test methods for cable condition monitoring. The IEC 62465 is concerned with cable conductors while the IEC 62582 will address cable insulation and jacket material.

Although no new cable material has been introduced in recent years, advances have been made in improved cable qualification and testing methods and it is now timely for the IAEA to lead an effort to bring the international cable experts together through this CRP to compile their experience and establish the road to the future.


Overall Objective

The goal of this CRP is to provide the current and next generation of nuclear facilities with information and guidelines on how to qualify new cables, monitor the performance of existing cables, and establish a program of cable aging management for both the current fleet of reactors and the next generation of nuclear facilities. This goal of the CRP will be reached through the execution of the following objectives:

  • Assemble a group of experts from around the world to provide input on cable qualification, condition monitoring, and aging management for both the current fleet of nuclear reactors.

  • Compile the current knowledge in a report together with areas of future research and development to cover aging mechanisms and means to identify and manage the consequences of aging. For example, the question of cable aging for the cables that are protected under fire protection layers will be addressed.

  • Establish a benchmarking program whereby cable samples are tested by various methods and various organizations and results compared to identify the best methods and establish a uniform program to address cable aging. This round-robin test will include both the qualification question and the cable condition monitoring question.

  • Determine the relationship between cable performance and signal quality, plant safety, and interference issues including EMI/RFI effects arising from cable problems.


Work Plan

Upon approval of CRP, a Chairman will be identified and cable experts will be attracted to commit to a 3 to 5 year program to work on the following tasks:

  • To identify the type, manufacturer, and physical characteristics of low voltage cables that are important to safe operation of nuclear power plants.

  • Provide recommendations on cable qualification methods that meet regulatory requirements and comply with the latest in industry standards and national and international guidelines. Also, to address how new scientific knowledge in materials area apply to cable qualification.

  • Identify the state-of-the-art in cable condition monitoring methods. Both environmental monitoring and cable testing techniques shall be included in this task. Emphasis will be placed on non-intrusive and in-situ methods that offer practical cable aging management in nuclear facilities.

  • Compile the nuclear industry's experience with cable aging, cable condition monitoring, and events involving cable failures affecting plant operation, availability, reliability, and safety.

  • Identify and acquire cable samples for benchmark experiments. These samples shall include new cables, aged cables, and cables removed from decommissioned plants.

  • Conduct benchmarking to establish effective cable qualification and cable condition monitoring and in-situ testing methods.

  • Identify research needs of the nuclear industry in the area of cable qualification, condition monitoring, in-situ testing, and cable aging management. Factors affecting cable insulation material shall be emphasized.

  • Produce two reports to document the outcome of the above tasks and the benchmarking exercise. The first report is to compile the expert knowledge in the CRP subject and the second report (published concurrently with the first report) shall include the details of benchmarking.

  • The CRP shall also focus on future R&D needs of member states in the cable area.


Potential Participants

Experts from a wide spectrum of disciplines from the nuclear industry and scientific community will be invited to contribute to the CRP either as a Chief Securities Officers (CSIs) or Observers. In particular, representatives for the following organizations will be targeted as CSIs and Observers in the CRP. These organizations were selected based on their current or past involvement in the area of this CRP:

  • Cable manufacturers
  • Research laboratories
  • Nuclear Regulatory agencies
  • International organizations
  • Universities
  • Engineering firms
  • Plant designers and vendors
  • Consultants with subject area expertise

Activities


Date Meeting Location
16-19 Apr 2012 First Research Coordinated Meeting on Qualification, Condition Monitoring, and Management of Aging of Low Voltage Cables in Nuclear Power Plants IAEA, Vienna,
Austria
1-2 Aug 2011 Consultancy Meeting to Prepare the Scope and Benchmark Approach Knoxvillee,
Tennessee, USA


Please contact NENP Engineering Section - Contact Point if you have any questions.