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~ Pergamon Radiat. Phys. Chem. Vol. 52. Nos I 6, pp. 499 503, 1998 ! 1998 ElsevierScienceLtd. All rights reserved Printed in Great Britain Plh S0969-806X(98)00037-1 0969-806x/98 SI9.00 + 000 Radiation Safety Training for Industrial lrradiators: What Are We Trying To Accomplish? M. A. Smith SteriGenics International 10811 Withers Cove Park Drive, Charlotte, NC 28273, USA ABSTRACT Radiation safety training at an industrial irradiator facility takes a different approach than the traditional methods and topics used at other facilities. Where the more routine industrial radiation users focus on standard training topics of contamination control area surveys, and the traditional dogma of time, distance, and shielding, radiation safety in an industrial irradiation facility must be centered on preventing accidents. Because the primary methods for accomplishing that goal are engineering approaches such as safety system interlocks, training provided to facility personnel should address system operation and emergency actions. This presents challenges in delivering radiation safety training to an audience of varied educational and technical background where little to no commercially available training material specific to this type of operation exists. training; radiation safety; irradiator. KEYWORDS INTRODUCTION Facility radiation safety programs are a much-discussed and analysed topic. Typically, such programs revolve around a variety of radioactive material or x-ray machine uses and address different aspects of ensuring safe operations for the persons involved. A traditional radiation safety training program includes contamination control, maintaining doses as low as reasonably achievable (ALARA), routine surveys, and implementing the classic radiation protection triumvirate of time, distance, and shielding. A basic assumption is that there are radiation sources that are being handled or manipulated in the course of work at the facility. Even in programs such as industrial radiography, which involve high-energy x-rays or relatively large radioactive sources, the emphasis is on handling the radiation source safely. For an industrial irradiator, the source of radiation is significantly larger than and the approach to radiation safety must be different. There is no "handling", per se, except for occasional source loadings in a gamma irradiator. Instead, the principal focus of radiation safety is preventing accidents wherein a person earl enter the irradiation cell when radioactive material is unshielded or the electron-beam accelerator is energized. Where the traditional radiation safety program concentrates on reducing personnel exposures to maintain low levels of risk, the industrial irradiator program is primarily directed at preventing a massive personnel exposure to preclude acute radiation exposure symptoms. Central to an irradiator's program is the safety system, which consists of a series of engineered features designed to prevent access to the irradiation room whenever unsafe levels of radiation are present. For example, a Category IV gamma irradiator includes primary and back-up access controls, radiation monitors, water level monitors, warning lights, alarms, and other features (ANSI, 1984). Training for operators in such a facility is, of necessity, centered on the safety system, what can go wrong with it, and what happens if it does malfunction. While personnel should be cognizant of topics from the traditional radiation safety program, it is less important to understand, for example, rigorous contamination control procedures, than it is to know what warning lights mean. In training irradiator personnel, operations and procedures form the basis for radiation safety. 499

Radiation safety training for industrial irradiators: What are we trying to accomplish?

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~ Pergamon Radiat. Phys. Chem. Vol. 52. Nos I 6, pp. 499 503, 1998

! 1998 Elsevier Science Ltd. All rights reserved Printed in Great Britain

P l h S0969-806X(98)00037-1 0969-806x/98 SI9.00 + 000

Radiation Safety Training for Industrial lrradiators: What A r e

W e T r y i n g T o A c c o m p l i s h ?

M. A. Smith

SteriGenics International 10811 Withers Cove Park Drive, Charlotte, NC 28273, USA

A B S T R A C T

Radiation safety training at an industrial irradiator facility takes a different approach than the traditional methods and topics used at other facilities. Where the more routine industrial radiation users focus on standard training topics of contamination control area surveys, and the traditional dogma of time, distance, and shielding, radiation safety in an industrial irradiation facility must be centered on preventing accidents. Because the primary methods for accomplishing that goal are engineering approaches such as safety system interlocks, training provided to facility personnel should address system operation and emergency actions. This presents challenges in delivering radiation safety training to an audience of varied educational and technical background where little to no commercially available training material specific to this type of operation exists.

training; radiation safety; irradiator.

KEYWORDS

I N T R O D U C T I O N

Facility radiation safety programs are a much-discussed and analysed topic. Typically, such programs revolve around a variety of radioactive material or x-ray machine uses and address different aspects of ensuring safe operations for the persons involved. A traditional radiation safety training program includes contamination control, maintaining doses as low as reasonably achievable (ALARA), routine surveys, and implementing the classic radiation protection triumvirate of time, distance, and shielding. A basic assumption is that there are radiation sources that are being handled or manipulated in the course of work at the facility. Even in programs such as industrial radiography, which involve high-energy x-rays or relatively large radioactive sources, the emphasis is on handling the radiation source safely. For an industrial irradiator, the source of radiation is significantly larger than and the approach to radiation safety must be different. There is no "handling", per

se, except for occasional source loadings in a gamma irradiator. Instead, the principal focus of radiation safety is preventing accidents wherein a person earl enter the irradiation cell when radioactive material is unshielded or the electron-beam accelerator is energized. Where the traditional radiation safety program concentrates on reducing personnel exposures to maintain low levels of risk, the industrial irradiator program is primarily directed at preventing a massive personnel exposure to preclude acute radiation exposure symptoms.

Central to an irradiator's program is the safety system, which consists of a series of engineered features designed to prevent access to the irradiation room whenever unsafe levels of radiation are present. For example, a Category IV gamma irradiator includes primary and back-up access controls, radiation monitors, water level monitors, warning lights, alarms, and other features (ANSI, 1984). Training for operators in such a facility is, of necessity, centered on the safety system, what can go wrong with it, and what happens if it does malfunction. While personnel should be cognizant of topics from the traditional radiation safety program, it

is less important to understand, for example, rigorous contamination control procedures, than it is to know what warning lights mean. In training irradiator personnel, operations and procedures form the basis for radiation safety.

499

500 M.A. Smith

MAJOR CAUSES OF IRRADIATOR ACCIDENTS

In 1996, the International Atomic Energy Agency (IAEA) published a report evaluating accidents in industrial irradiators and drew conclusions as to primary causes of accidents and what can be done to prevent recurrence (IAEA, 1996). In this report, three areas were defined as being the root cause for the accidents studied.

Design Problems

Contributing to accidents were either a flaw in initial design of the irradiator, which allowed unsafe conditions to occur and not be detected, or failure of the operating organization to maintain the irradiator to meet the design, such as ensuring that radiation monitors were functioning properly. Also, modifications in operations contributed to creating a situation that was not anticipated in the initial design.

Incomplete Safety System

In the accidents studied, some component of the safety system was either not present or not operating, either from component malfunction and failure to repair the equipment or from a deliberate action on the part of the operating organization to defeat or bypass the safety system.

Lack of Knowledge The most critical component in any safety system is the irradiator operator. In the IAEA report, every accident involved operator error. In some cases, personnel were either misinformed or did not possess knowledge to understand the system and what problems were present. In others, a conscious decision was made to ignore conflicting information or deliberately defeat the system.

From these root causes, the areas in which a training program must focus become apparent. An effective radiation safety training program must thoroughly address these causes, while introducing enough general information and theory (e.g., types of radiation, units of dose, biological effects, etc.) to provide context for understanding consequences.

FOCUS AREAS FOR IRRADIATOR OPERATOR TRAINING

In the United States, regulations (NRC, 1993) and draft guidance documents (NRC, 1994) from the Nuclear Regulatory Commission provide a good starting basis for designing a radiation safety training program. Although designed for facilities using radioactive material, electron beam or particle accelerator facilities can also make beneficial use of these outlines. Three areas deserve greatest focus.

Safety System Design and Operation An irradiator operator must understand how the safety system works and what the indicators are actually reporting. Obviously, avoiding initial design flaws is not possible through training programs. However, it is possible and desirable to provide enough training on design and operation of the safety system that an operator can detect and report design problems if they exist, not necessarily to the point of recommending corrective action, but at least to the extent of recognizing that something is wrong.

To start, emphasize the importance of the safety interlocks. They exist to prevent extremely bad things from happening to anyone who enters the irradiation room. Central to the design is the access control method, wherein an individual is be prevented from entering the room when unsafe conditions exist. The operator must understand how the system controls access and, most importantly, learn not to tinker with the access controls. Three points, if completely grasped, will greatly enhance the ability to avoid accidents such as described in the IAEA report.

(i) Bypassing or getting around the interlocks has potentially fatal consequences. The operator must

intuitively believe that if he or she defeats the system, dire results will almost undoubtedly ensue. A corollary is that the system must be designed such idea that proper and safe operating procedures

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are also the easiest approach. If it is less time consuming or labourious for an operator to get around the system than it is to follow the design procedures, invariably some enterprising individual will decide to take the easier route. Remember the fundamental rule: The easiest way to do a task will be followed; design that to be the safest way, too.

(2) If the safety system doesn't operate the way it is designed, get it repaired. In accidents from the IAEA report, some component of the safety system had failed. Instead of replacing the component or repairing the system, the operating organization bypassed the malfunctioning equipment. Individuals operating the irradiator must be trained to the point that this is an unthinkable solution.

(3) If there are conflicting signals, believe the worst. At least one accident occurred because an operator received conflicting signals from the safety system. One indicator, which had been known to fail, indicated that the radioactive sources were not shielded. Another, which was generally not prone to failure, indicated the irradiator was in a safe condition. The operator assumed the first was wrong and the latter correct. Unfortunately, the reverse was true and the operator entered the irradiator with the sources exposed. Training programs must condition irradiator operators to believe the worst case scenario always applies. This may occasionally lead to taking conservative actions when not absolutely necessary, but it will avoid not taking such actions when they are appropriate.

Operating and Emergency Procedures

Radiation safety Iraining for irradiator operators is, of necessity, operationally based. Covering the procedures for safe operation of the irradiator, particularly for entering the irradiation room, should form the fundamental emphasis for the training program. Of all the various topics that can be included, the most important are

(1) Always, regardless of any other indicator, carry an operating radiation survey meter when entering the irradiation room and pay attention to what the meter is reading. Even if all other safety system features are defeated, a radiation survey meter will indicate whether the sources are exposed or the accelerator is energized. Believe the meter when it shows high readings.

(2) When the safety system alarms indicate a problem, respond appropriately. Do not automatically assume the system is in error and try to correct or defeat it. Do not try to repair a perceived system malfunction without first calling someone who understands the design. What may be thought to be a malfunction may actually be a correctly operating system. Convey the message that an irradiator is almost invariably safe for the operator if that individual locks the access door and does not try to enter the irradiation room.

What Happens When Something Goes Wrong

When something does go wrong, it is crucial that the operator understands something is not right and fully appreciates the consequences. To instill this perspective, the training program should devote time to explaining biological effects of ionizing radiation and, in particular, reviewing case histories of irradiator accidents. From this, the operator will apprehend that such things have happened before and can possibly occur again. There is little doubt as to what will occur to an individual exposed to inordinately high radiation levels and the margin for error is slight if the decision is made to enter the cell.

CHALLENGES IN RADIATION SAFETY TRAINING

Knowing what needs to be presented in the radiation safety training program is significantly different from being able to deliver training in a concise, coherent manner and ensure that the personnel fully understand the concepts. As a practical matter, there are several challenges to presenting a successful training program.

Defining Training Content for Different Job Functions

An irradiator facility will typically employ a variety of personnel at different levels within the organization. Warehouse personnel, who unload and load product from trucks and onto the conveyor system through the

502 M.A. Smith

irradiator, tend to be low-wage workers, typically with relatively low educational levels and an incomplete understanding of scientific or technical concepts. Managers, such as production managers or quality assurance managers, may typically have college degrees, although not necessarily in science or technology fields. Obviously, the message has to be directed to the target audience. Multiple training sessions, geared for different audiences, are almost mandatory. Concepts should be explained in simple terms to start, progressing toward more complex understanding as the individual's knowledge grows. Fundamentally, trainers must explain the pertinent information as much as necessary for each person to understand it.

At all employment levels, personnel must be ingrained with the attitude that, if something is not working correctly, be it a procedure that is incorrect or not being followed or a function of the safety system that does not perform as designed, it is each individual's responsibility to report the problem to someone who can ensure it is repaired. Also, everyone working in the facility needs to be made aware of the safety system alarms and the appropriate actions to take if and when those alarms sound.

Levels of Language Skills

In the United States, there is a significant probability that, in any grouping of workers in lower wage occupations, such as warehouse workers in an irradiator, there will be some persons in the organization whose command of English is marginal. In countries where English is not the primary language, an irradiator may be constructed by a company from a country where primarily English is spoken. In such circumstances, manufacturer-supplied operating procedures and descriptions are likely to be in English, which should be translated into the native language. It is likely that the radiation safety training program will include at least some individuals whose native language is something other than that of the trainer or the reference material. This can and does create significant communication problems.

Whenever possible, interpreters should be provided as necessary for classroom-style training sessions. A better approach would be to use trainers, either staffor contract employees, whose native language is the same as the audience or who are fluent in that language. While the presence of interpreters in a classroom has disadvantages, if the message is delivered, it is worthwhile.

Lack of Industry-Specific Training Materials

Inavailability of industry-specific training materials is a generic problem. There are few, if any, commercially available training materials and reference texts specific to industrial irradiators. Most commercial radiation safety training courses, for example, are designed to provide an introduction in radiation safety to a wide variety of radiation users in decidedly different applications. The market for industrial irradiator training is so small that there are few commercial courses that adequately cover the pertinent issues. In addition, a significant amount of time in most commercial courses is spent on topics that are of lesser importance at an irradiator than at other facilities (e.g., contamination control).

Therefore, it is entirely likely that any organization operating an irradiator will have to develop their own training program, materials, and reference texts. The previously-cited NRC, ANSI, and IAEA documents provide a good starting point for topics and reference materials. Other sources include a variety of health physics textbooks and related publications. In any event, a significant amount of work will be involved in sorting through the available information and extracting that which is pertinent to irradiator operations.

Methods for Delivering Training

The traditional methods of delivering training rely on individuals sitting in a classroom while the "expert" lectures the class on the topics at hand. While there are several advantages to this approach, most significant of which is the discussion fostered in such an environment, implementing a training program with classroom lectures as the primary delivery method presents some additional challenges.

First, the point in the individual's employment where this training should occur needs to be considered. For operators, spending some time learning the system operations under the tutelage of an experienced operator

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prior to embarking on a formal training program is the best approach. In this way, the individual already has some knowledge of how the system operates and many of the concerns addressed in the operating and emergency procedures, which provides a sound basis for the formal training. Obviously, it is important that the on-the-job aspects are conducted properly, such that the individual learns the correct methods, and is not subjected to any "short cuts."

The style of training delivery should be tailored to the individuals' best learning methods whenever possible. Some individuals learn better through tactile experiences, while others can absorb material better in a lecture format. Some combination of classroom discussion and hands-on demonstrations is best. One area in which the hands-on approach is definitely an advantage is emergency procedure training. Conduct emergency drills as realistically as possible. While some emergency situations would be impossible, or at least extremely undesirable, to create (e.g., stuck source rack in a gamma irradiator), almost all situations can be simulated realistically enough to give individuals an adequate picture of what actually occurs in an emergency.

Alternative means of delivering training have been proving to be beneficial. Self-study or directed study, wherein the individual reads and studies reference material alone, which is then supplemented through classroom sessions, discussions, and hands-on experience, typically is the most effective method for training, both in terms of the time investment involved and in the ability of the individual to retain important information. However, in many circumstances, such as with individuals having low literacy skills, self-study can be problematic.

Computer-based training has become more popular in many areas in the past several years. There are distinct advantages to using computer-based training foi~tadiation safety: individuals can establish their own pace, in-process testing allows better definition of areas needing emphasis, and presentation of training material is consistent, whereas an instructor probably will not present the same material in the same way each time. The greatest disadvantages of computer-based training, though, are a still-prevalent computer phobia and inavailability of commercial packages specifically for irradiators. Each company is left with the task of developing their own computer-based training program, which is a significant commitment of resources.

CONCLUSIONS

Radiation safety in an industrial irradiator depends first on engineered features to protect individuals. Training programs at such facilities should emphasize these features and their proper operation, but also ensure that the individuals being trained understand what can and has gone wrong with similar systems and what steps to take if or when that does occur. The most important aspect, as with any effective training program, is to tailor the instruction and material being presented to what the individual needs to know and his or her ability to absorb the pertinent facts. A variety of source material is available to develop an irradiator radiation safety training program, but there are essentially no off-the-shelf packages. This is advantageous in that each company's program will necessarily be geared specifically to that company's operations, but presents the disadvantage of significant investments in time and effort to develop an adequate and effective program.

REFERENCES

American National Standards Institute (ANSI, 1984) American National Standard N43.10; Safe Design and Use of Panoramic, Wet Source Storage Gamma Irradiators (Category IV), National Bureau of Standards Handbook 142, U. S. Department of Commerce

International Atomic Energy Agency (IAEA, 1996) Lessons Learned from Accidents in Industrial Irradiation Facilities

U. S. Nuclear Regulatory Commission (NRC, 1993) Licenses and Radiation Safety Requirements for Irradiators, Title 10, Code of Federal Regulations, Part 36

USNRC (1994) Guide for the Preparation of Applications for Licenses for Non-Self-Contained Irradiators, Draft Regulatory Guide DG-0003