Global Best Practices for Material Control and Accountability (MCA)

From the Special International Workshop on Global Best Practices in Materials Accountancy, Control held June 7 – 11, 2004, Prague, Czech Republic

MCA1. Identify MCA program terms, principles, and objectives.
Because clear and precise definitions of terms, principles, and objectives are necessary for effective communication, a glossary should be prepared that concisely defines the terms, principles, and objectives used by the State.

Principles should be established that promote accurate, complete, and timely data and records on nuclear material accountability and that support the ability to verify data independently.

Objectives should be identified that detect and deter the loss, theft, and diversion of nuclear material; meet international safeguards agreements and standards as well as regional and national legislation and regulations, and other requirements such as bilateral agreements and contractual agreements; and form the basis for an effective physical protection system. A graded approach is a useful tool to help meet these objectives.

MCA2. Establish an effective MCA organization.
Program administration, implemented by nuclear material sites, should ensure that the program addresses critical functions, establishes appropriate authorities and responsibilities, supports the nuclear material missions at the site, and facilitates integration with other programs such as operations and health and safety. It should also address strategic planning for new systems and technologies, and changes in facility designs. Program administration should provide training and qualification for those who perform control and accounting functions and use employee feedback to strengthen system performance.

Best practices for the structure of an MCA organization:

  • The roles, responsibilities, and authorities of the MCA manager and organization should be well defined and communicated, and should include the authority to cease production in the event of an anomaly with nuclear materials control and accountability.
  • The MCA organization should be independent from organizations with responsibility for production so that inherent conflicts between MCA and production can be resolved at a management level sufficient to ensure the appropriate level of checks and balances.
  • The MCA organization should develop and implement a comprehensive plan for recruitment, retention, and promotion of MCA personnel to counter the universal problem of "brain drain" experienced in this specialized area.
  • The MCA organization should be positioned within the overall organization structure to facilitate ease of communication with the State System for Accounting and Control (SSAC) and/or national level tracking system.
  • Organization structures should facilitate the integration of safeguards and security elements into operational and safety and health-related organizations.

MCA3. Develop, implement, and validate measurement methods capable of providing the required levels of accuracy and precision.
Nuclear material inventory quantities should be established upon creation or receipt of a new item, or when there are changes in quantity, physical form, or chemical form. These quantities should be reestablished periodically to reduce uncertainties such as when there are improved measurement capabilities. Measurement methods, instrumentation, and personnel should be subject to a formal qualification program. A measurement control program should be established that employs reference materials and standards; identifies precision and accuracy values, monitors; monitors and controls measurements; and quantifies measurement errors used in the statistical evaluation of material control indicators. The nuclear materials site is responsible to implement the measurement program in a way that meets the stated objectives of the state regulatory authority.

Sources of measurement errors should be identified and, to the extent possible, reduced or mitigated. Examples of this include effects of external factors such as humans, humidity, and heat. Measurement systems and people operating them should be qualified and benchmarked (for example, blind samples and external sample exchange programs).

Ideally, nuclear materials measurement methods should be chosen to minimize the uncertainties of the nuclear material accountability value. However, this is not always practical given the cost and amount of material. When determining what measurement methods to use, several parameters should be considered, including: nature of operations, availability of equipment, cost, personnel exposure, precision and accuracy goals (both national and international), field conditions, material attributes, material containers, and the material matrix.

Challenging areas for measurements are related to their potential to be used as a diversion path or to negatively impact the ability of the facility to draw an accurate material balance. These areas include waste streams and material in process holdup. Waste streams should be continuously monitored and measured using methods capable of detecting diversion of nuclear materials. Waste measurements should be capable of providing sufficient precision and accuracy to meet national and international requirements and provide sufficient information for both MCA and waste management programs in the units required.

A wall-to-wall hold-up measurement program should look at material in hold-up in the expected locations and also in unexpected locations. When possible, equipment hold-up measurements should be validated by using other measurement techniques, after the equipment has been removed and either completely dissolved or cleaned out.

Best practices for nuclear material measurement systems:

  • Accredit measurement systems using international standards such as ISO17025.
  • Incorporate measurement equipment into the design of new facilities at key measurement points; these points should be determined based upon the ability to localize inventory or process differences.
  • Promulgate a policy that provides incentives for better measurements (for example, lowering the uncertainty of the material measurements could increase the time between physical inventory periods).
  • Validate measurement equipment, techniques and sampling practices to assess performance of the measurement system using both internal and external resources such as a standards exchange program or in-house alternative measurement methods.
  • Employ repeatable, reliable, and simple techniques adequate to meet multiple needs (such as MCA, operations, health-safety, and criticality).
  • Facilitate timely identification and resolution of anomalies while minimizing human error rates using near-real time measurements and results, automated data collection and transfer, and automated analysis.
  • Ensure integrity of measurement systems and resulting data and analyses by employing both hardware and software protection measures.
  • Calibrate equipment and use frequent calibration checks and statistical analyses to determine if the equipment's calibration remains in statistical control before and after measurements.
  • Maintain reliable source and composition information and process history of the nuclear material in order to determine optimal sampling and measurement techniques.
  • Establish a robust personnel training and qualification program specific to measurements as the area is highly specialized, including mentoring to facilitate the transfer and continuity of process knowledge.
  • Integrate remote monitoring with other MCA and security systems to eliminate or reduce measurement requirements.
  • Develop new measurement technology to address identified problem areas such as in situ holdup monitoring.

MCA4. Establish a complete, accurate, and timely record of the entire nuclear material inventory.
The accountability system should track the total quantity of nuclear material and record the characteristics, location, and unique item identity for each nuclear material item. It should be able to provide a complete audit trail for all nuclear materials from receipt through disposition, including documentation of all nuclear material transactions. Measures should be established and checks implemented to ensure data accuracy and detect any unauthorized access to data. Accountancy is the responsibility of each nuclear materials site. The regulatory body should ensure standardization of data from each site, oversee the work and compile a complete state-wide inventory.

The nuclear material item should be established as the basic accounting entity. The item should have a unique identity, and the accounting records should reflect the characteristics and location of the item.

The fundamental accounting structure for nuclear material is the material balance area (MBA). MBAs should be established to localize inventory differences and meet international reporting requirements, while reducing, to the extent possible, the burden of the operator in generating reports.

Best practices for establishing an MBA:

  • An MBA should correlate to a bounded (physical or administrative) and monitored location(s).
  • The MBA should not be so large that it cannot localize inventory or process differences to a manageable area.
  • Materials transferred into and out of an MBA must have quantitative measurements.
  • In order to provide transparency in international safeguards and protect commercially sensitive information, a facility should have the capability to establish special MBAs to meet specific needs.
  • Each MBA must have an assigned custodian tasked solely with MCA responsibilities. The MBA Custodian should be located within the physical operations area and act as the direct interface with the MCA organization. The MBA Custodian responsible for more than one MBA should not have the ability to transfer material between MBAs under his control to prevent diversion.

Best practices for accounting systems:

  • As a baseline and as applicable, nuclear material accounting systems should be consistent with generally accepted accounting principles.
  • Accounting systems should be automated to the extent practical--the accounting system should interface with measurement and monitoring equipment and incorporate automated data entry and paperless transfers.
  • Accounting systems should be user-friendly and customer-oriented with an intuitive interface, flexible reporting capabilities, and, to the extent possible, integrated with other systems such as quality, safety, production, etc.
  • The integrity of the system and the data should be ensured by the employment of software quality assurance validation activities (redundant systems, configuration and change control), access controls (both hardware and software), encryption, and authentication.
  • The accounting system should have the capability to track and provide traceability for material on inventory and perform evaluations of the data.
  • The accounting system should be capable of providing timely anomaly resolution.
  • In processing environments, monitoring of the material throughout the process in well defined areas should be employed to facilitate operations, quality assurance, and localization of process and inventory differences.

MCA5. Establish a system for materials control using well defined geographical areas within the site.
Nuclear materials should be used, processed, and stored only in areas that have been identified for these purposes and that have appropriate physical and administrative controls. Thus, each nuclear materials site should establish well-defined geographical areas wherein the location and quantity of all nuclear materials are identified and controlled. Area boundaries should not overlap. The material types, forms, and quantities permitted in each area should be precisely specified. All movements of people and materials into and out of these areas should be carefully monitored and controlled. Material transfers between areas should be based on measured values, and waste streams should be monitored.

Each site should implement appropriate physical security and administrative controls to permit controlled access to the area by personnel and prevent any unauthorized access. Alarms and procedures to assess anomalies should be established.

Not all the equipment necessary for an effective material control program has to be "high tech;" the application of inexpensive tamper-resistant seals coupled with a strong material surveillance program are sufficient for maintaining continuity of knowledge of the material in inventory.

Containment and surveillance measures provide assurance that the integrity of nuclear material values is maintained. Unattended remote monitoring and measurement systems for containment and surveillance purposes can provide several benefits, including reduced need for operator and inspector access, greater transparency, greater flexibility and possibility for on-line measurements, more accurate and timely results, reduced operational costs, and reduced personnel radiation exposure.

Best practices for material control:

  • Choosing the appropriate equipment for containment and surveillance measures consistent with their intended use (threat) considering the following parameters:
    • Ease of use and maintainability
    • Reliability
    • Ability to archive and retrieve data
    • Life expectancy (of equipment)
    • Supply chain management (procurement)
    • Capability for real time data collection and analysis.
  • Standardizing to the extent possible using common system sensors or device communications and data collection standards.
  • Integrating systems with physical security, safety, or other pertinent systems while minimizing impact on operations (equipment should be unobtrusive).
  • Ensuring the integrity of containment and surveillance systems by employing software quality assurance validation activities (redundant systems, configuration management, and change control), access controls (both hardware and software), encryption, and authentication.
  • Negotiating dual (joint) use of containment and surveillance systems in international inspection regimes.
  • Conducting vulnerability testing and assessments on a regular, ongoing basis to include testing under field and operations conditions.
  • Promulgating a policy that allows for increased time between physical inventories with the application of a robust material control program/containment and surveillance systems.
  • Identifying, eliminating or reducing human factors by employing automated containment and surveillance measures.
  • Ensuring competence in technical staff for application, inspection, removal, and evaluation of common support measures (human reliability assessments).

Back to Best Practice Home Page