Issue:

During a recent Department of Energy (DOE) Office of Environment, Safety and Health, Safety Management Evaluation (SME) at a DOE facility, an issue was raised concerning adequate controls for entrances or access points to high radiation areas where radiation levels exist such that an individual could receive a deep dose equivalent exceeding 1 rem to the whole body in any 1 hour at 30 centimeters from the source or from any surface that the radiation penetrates (e.g., hereinafter referred to as "physically controlled high radiation areas"). The SME assessor noted that a shipping cask door was not locked as required by a site implementing procedure. The door of the cask could be opened manually using an attached hoist by lifting and rotating a pin and then operating a hand crank. It was estimated that opening the door would generate a radiation field outside the cask of approximately 25 rem per hour. With the cask door closed the radiation field exterior to the cask was less than 100 millirem per hour. The cask was not labeled to warn of the high radiation field should the door be opened.

The DOE contractor involved agreed that, per site implementing procedures, the cask door was required to be locked. However, the contractor requested additional guidance regarding an acceptable approach to implementing high radiation area access controls for casks or other radioactive material containers.

The above situation identifies two areas where guidance is needed. The first area regards an acceptable approach for implementing the requirements of Title 10, Code of Federal Regulations, Part 835 (10 CFR 835), "Occupational Radiation Protection," section 835.502, "High and very high radiation areas," for access controls for containers of radioactive material in controlled areas such as shipping casks, which generate physically controlled high radiation areas external to the container only when the container is opened (i.e., radiation levels exist external to the container only when the container is opened).

There are other requirements for containers of radioactive material that generate lower radiation fields such as the access controls contained in 10 CFR 835.501. In addition, 10 CFR 835, subpart K, specifies design and control requirements to keep exposures within limits and as low as reasonably achievable. These requirements are not addressed in this technical position.

The second issue concerns the need to lock access points or entryways that are secured shut by means other than with a key or combination type lock (i.e., bolted or requiring the use of a hoist or other lifting device).

Introduction:

10 CFR 835 establishes requirements for control of radiological areas. Subpart F, "Entry Control Program," contains general requirements for controlling entry to all radiological areas. In addition, subpart F contains additional controls for controlling entry to physically controlled high radiation areas.

Additionally, subpart G of 10 CFR 835 establishes requirements for posting and labeling areas and containers for radiological protection, and subpart J specifies the training needed for all general employees working in controlled areas.

Discussion:

Applicable Requirements

§ 835.501 Radiological areas:

§ 835.502 High and very high radiation areas:

§ 835.601 General requirements:

§ 835.901 General employees:

Technical Position:

Issue 1: Acceptable approach to implementing access controls per § 835.502 for containers of radioactive material

The question regarding an acceptable approach for implementing access controls per 10 CFR 835.502 for containers of radioactive material in controlled areas concerns containers that generate physically controlled high radiation areas external to the container only when the container is opened.

There are many situations where, when the access points of a radioactive material container are closed, there are no physically controlled high radiation areas exterior to the container. In some of these situations, opening on access point creates a physically controlled high radiation area exterior to the container. An acceptable approach for these situations is to implement one or more of the features of 10 CFR 835.502 for the container. This approach would be consistent with the requirements of 10 CFR 835.502 in acting to prevent uncontrolled or unplanned exposures to individuals.

In addition, in situations where an individual could enter a container and access a physically controlled high radiation area, one or more of the features of 10 CFR 835.502 should also be implemented for the container. In this case, the walls of the container form the boundary of an accessible physically controlled high radiation area.

The 10 CFR 835.502 features discussed above could include either controlling access to the container itself or controlling access to the room where the container is residing.

This position is consistent with the approach the Department endorses for control of exposures associated with radiation generating devices in the Implementation Guide for use with Title 10, Code of Federal Regulations, Part 835, "Occupational Radiation Protection - Radiation-Generating Devices" (G-10 CFR 835/C3 - Revision 1, November 1994) and referenced national standards therein referenced. This position is also consistent with the approach being implemented by the Nuclear Regulatory Commission (NRC) in their regulations and supporting Regulatory Guide. See references 3 and 4 for detailed information.

Issue 2: The need to control access to entryways that are secured shut by means other than with a key or combination type lock

In the previously discussed situation, the room where the container was located was not locked. However, a hoist was needed to open the container. 10 CFR 835.502 (a)(4) requires, in part, that applicable entryways be locked. Generally, entryways that are secured closed in such a manner that a tool, such as a hoist, must be used to gain access, may be considered locked. However, in the previously discussed situation, because the lifting hoist was left in place, an individual would not need to make a determined effort to open the cask. Accordingly, the entry, in this situation, would not be considered adequately locked or otherwise secured. Similar unacceptable examples would include leaving a ladder secured adjacent to a fence meant to restrict access or securing an entryway with a single bolt and leaving the wrench attached to the bolt. These examples are analogous to the unacceptable situation of locking an entryway with a key lock and leaving the key in the lock. These examples are not considered consistent with 10 CFR 835.501(b), which requires that the degree of control be commensurate with existing and potential radiological hazards within the area.

While the purpose of locking these areas is to maintain a high level of positive access control, it is recognized that these controls cannot absolutely prevent determined circumvention of the physical barrier such as with the use of wire cutters or unbolting the hinges to a doorway. Instances of such determined circumvention should be addressed with appropriate disciplinary action.

This position is consistent with commercial industry guidance given by the NRC in a Regulatory Guide. See reference 4 for detailed information.

In addition to the above mentioned controls, in situations such as that described at the beginning of this technical position, the entryways or access point to the container would also need to be labeled, per 10 CFR 835.601, if adequate warning is not provided by control measures and required posting. The label should specify that the entryways should not be opened without radiological control approval and that significant levels of radiation may exist. In the above referenced situation, neither container labeling nor other posting was implemented to warn individuals not to open the container.

Also, all individuals in the controlled area need to be trained, in accordance with 10 CFR 835.901 (a), in radiation safety prior to receiving occupational exposure during access to controlled areas at a DOE site or facility. This training would need to address the importance of following posting and labeling directions as well as the site specific information and policy concerning the use of tools to open entryways.

References:

1. 10 CFR 835, "Occupational Radiation Protection," U.S. Department of Energy, December 14, 1993.

2. Implementation Guide for use with Title 10, Code of Federal Regulations, Part 835, "Occupational Radiation Protection - Radiation-Generating Devices," G-10 CFR 835/C3 - Revision 1, November 1994.

3. 10 CFR 20, "Standards for Protection Against Radiation, U.S. Nuclear Regulatory Commission, January 1, 1996.

4. U. S. Nuclear Regulatory Commission Regulatory Guide 8.38, "Control of Access to High and Very High Radiation Areas in Nuclear Power Plants," June 1993.