Chapter 9 Table of Contents. View the entire chapter in a PDF format. Please use the pdf for printing.

Requirements:
Procedures and Specific Requirements (Section 5.2)

All radiological work at SLAC must be authorized by line management and approved by cognizant Radiation Protection (RP) Department personnel. Radiological work must be conducted by trained personnel who are following written procedures and a radiological work permit (RWP). The following section describes procedures and requirements that apply generally to all personnel at SLAC. Implementing documents can be found in Section 6.

Controlling Hazards (Section 5.2.1)

Radiological hazards at SLAC are controlled through engineering controls, administrative controls, and personnel protective equipment (PPE).

Engineering controls include the following systems or procedures:

• Radiation shielding
• Personnel protection system (PPS)
• Beam containment system (BCS)

Administrative controls including the following systems or procedures:

• Beam Authorization Sheet (BAS) [pdf] and Beam Line Authorization (BLA) [pdf]
• Radiation Safety Work Control Form (RSWCF)
• Radiological Work Permit (RWP)
• Area and worker classification

Engineered systems are preferred to administrative controls, although both are vital to the success of the radiation safety programs.

In addition to shielding, PPS, and BCS, interlocked radiation detectors called beam shut-off ion chambers (BSOICs), and burn-through monitors (BTMs) are part of the radiation safety system at SLAC. The BSOICs are placed outside the shielding enclosure to monitor and terminate unacceptable radiation levels.

See Radiation Safety Systems [pdf] and Chapter 3 of the RadCon Manual [pdf] for details regarding these measures.

Engineering Controls (Section 5.2.2)

Engineering controls are physical means designed to reduce, eliminate, or control hazards; they include passive controls (shielding and fences) and active controls (BCS).

Radiation Shielding

Radiation shielding and other physical barriers like fences are engineered safeguards designed to attenuate radiation or otherwise reduce the prompt dose rate to acceptable levels. Such passive engineering controls are preferred over active engineering controls, such as BCS, and administrative controls, such as ropes and signs. Administrative controls may be used to supplement the engineered controls and should be used only if adding shielding or other barriers is not practicable. All primary beams (original accelerator beams) and synchrotron radiation beams must be fully enclosed by shielding and barriers that cannot be circumvented in an unauthorized manner.

Shielding Design Criteria

During normal operations, all beam lines and experimental facilities must be shielded to control individual doses from external radiation to less than 1,000 mrem total effective dose equivalent (TEDE) per year (in general, 2,000 h/y occupancy is used) and also ALARA.

Shielding must also be designed to protect individuals under abnormal operating conditions (mis-steering and system-failure cases). See Radiation Safety Systems [pdf] for details.

Shielding Design Protocol

The RSO must approve shielding design specifications. The Radiation Physics Group (RPG) within the RP Department is responsible for determining the shielding required for a facility, and must be consulted prior to the construction of a new facility or the modification of an existing facility. To obtain approval of a shielding design from the RSO, it is the responsibility of the line manager (or designee) to provide information in writing and work with a radiation physicist within the RPG who is tasked with oversight of facility construction or modification where shielding is required. The radiation physicist will then propose a shielding design and seek concurrence from the RSO on the design.

Shielding Configuration Control

Any facility that requires radiation shielding will have an appropriate configuration control program to ensure the shielding is properly in place before and during accelerator operation (see SLAC Guidelines for Operations for details.). Such processes will be described in written procedures. The configuration control program also applies to all radiation safety-significant systems such as the PPS and BCS.

Personnel Protection Systems

At SLAC, the interlocked access control system is called the personnel protection system (PPS), which protects personnel from exposure to prompt ionizing radiation from beams and interlocked electrical hazards in the accelerator housing. A PPS consists of access interlock logics, display of access states, key controls, and other controls. The interlocked access control system that protects personnel from exposure to prompt ionizing radiation in synchrotron radiation beam line hutches is called the hutch protection system (HPS). The general design requirements, review, and approval of the HPS are similar to those described for the PPS.

New and modified PPSs, as well as PPS bypasses, must be approved by the RSO prior to implementation.

Accessible beam lines must have a PPS to protect personnel from prompt radiation. The PPS prevents exposure through the use of beam stoppers (or beam inhibiting devices). The PPS also prevents entry to beam enclosures when beams are operating and turns off beams when a security violation is detected.

The PPS must be established and maintained to be fail-safe. To meet this goal, the PPS is scrutinized continuously via configuration control, periodic certification, and testing of its physical and electrical components.

Before a new PPS is used for routine operation, it must be reviewed and documented by drawings and a written function description. PPS modification must also be documented, reviewed, and approved.

In the case of an access violation, the PPS will automatically terminate the radiation hazard by removing or redirecting beam and/or inserting metal plugs into the beam line path.

Key controls at access doors are used to account for personnel in accelerator and beam line housings when access states are in the controlled access configuration (each person has a key). Qualified operators enforce these key controls as personnel enter and exit accelerator housings. When keys are removed, the system provides a safety interlock to ensure a beam cannot be directed into areas occupied by personnel.

Large, illuminated signs are generally located adjacent to each major beam line housing entrance. The signs display access-state information (such as "No Access", "Restricted Access", or "Controlled Access") that alerts personnel to possible hazardous conditions in the beam line housing.

Beam Containment Systems

Radiation safety policy at SLAC requires that beams be transported within their designated channels to the designed termination point, such as a detector, beam dump, or injection into a storage ring.

If beams diverge from their proper channels, high radiation levels can occur in unprotected areas.

The beam containment system (BCS) prevents beams from diverging from the designated channel, and detects excessive beam power or beam losses that could cause radiation levels exceeding established radiation limits.

Containment of beams is usually accomplished by a combination of passive devices, such as collimators, that are designed to absorb errant beams, and active devices, such as electronic monitors, that shut off beams when out-of-tolerance conditions are detected.

Beam parameters such as energy and current, and/or beam losses in an area, may need to be monitored and limited by BCS devices to prevent excessive radiation levels outside the shielding enclosure. BCS devices are also used to turn off the beam if the beam power striking a device designated to contain it exceeds the power safety limit of that device.

The details of BCS design guidelines are described in Radiation Safety Systems [pdf].

Administrative Controls and Personal Protective Equipment (Section 5.2.3)

Administrative controls are safety policies, rules, supervision, posting, and work procedures designed to reduce duration, frequency, and severity of exposure to hazards.

Beam Authorization Sheet and Beam Line Authorization

A Beam Authorization Sheet (BAS) [pdf] and Beam Line Authorization (BLA) [pdf] is used to authorize the operation of a facility at SLAC and SSRL, or an SSRL beam line, respectively. The forms establish the pre-running conditions (including shielding PPS and BCS interlock checks), pre-run checks, and running conditions to ensure radiological safety during accelerator operations. The BAS and BLA are jointly prepared, issued, and approved by the RP Department, the facility safety officer, and operations manager representing the line organization. See the SLAC Guidelines for Operations for details.

Radiation Safety Work Control Form

A Radiation Safety Work Control Form (RSWCF) is part of the configuration control program, which is used to control work performed on, or that may affect, all radiation safety systems such as PPSs, BCSs, BSOICs, and shielding. The facility safety officer issues the RSWCF with approval from the radiation physicist. See the SLAC Guidelines for Operations for details.

Radiological Work Permit

A Radiological Work Permit (RWP) is used to control access to Radiological Areas or to announce radiological controls for work involving radiological hazards. See the Radiological Work Permit Procedure [pdf] for further information.

Workers at SLAC are classified according to the level of their training, which determines the areas they can enter without an escort. A GERT employee without a dosimeter can enter unescorted only into controlled areas. A GERT employee can also enter an RCAs unescorted as long as he or she has a personnel dosimeter and will not exceed 100 mrem TEDE in a year.

To enter any radiological area or a radiological buffer area, a worker must have a personnel dosimeter and RWT I-training or higher.

A key additional training-level consideration is that SLAC limits the annual TEDE dose to GERT employees to be no more than 100 mrem in a year. If a GERT employee is likely to receive a dose over 100 mrem TEDE in a year, he or she must first acquire RWT I training or higher.

All areas containing radiation hazards or having the potential to contain radiation hazards will be posted with the appropriate signs (see Radiological Safety: Radiological Posting and Signs [pdf]). The types of areas controlled for radiation hazards are described below.

Controlled Areas

The designation of a controlled area at SLAC corresponds to the definition in 10 CFR 835.2, which states that, "a controlled area means any area to which access is managed by or for DOE to protect individuals from exposure to radiation and/or radioactive material." A controlled area at SLAC is one in which an individual is not expected to receive more than 100 mrem TEDE in a calendar year.

Personnel at SLAC are required to be informed of the real or likely presence of radiation in a controlled area as part of safety training as specified in Section 5.3.

Personnel Exclusion Areas

Personnel exclusion areas are those secured by some physical manner other than by means of a PPS to keep personnel from accessing those areas during accelerator operations.

Radiologically Controlled Areas

RCAs without entering radiological areas are not expected to receive a TEDE of more than 100 mrem in a year.

Each RCA will be posted with the appropriate signs. An RCA can be designated for purposes of access control even if no radiological condition otherwise warrants the designation.

Radiological Areas

Radiological areas are those (including radiation areas, high radiation areas, contamination areas, airborne radioactivity areas, and so on) where distinct radiological conditions can be quantified and compared against established limits. Specific access controls, postings, and training requirements apply (see Section 6, “Exhibits”, and the RadCon Manual [pdf] for more details).

Radiological Buffer Area

A radiological buffer area can be established near a contamination area to help to facilitate contamination control, as deemed appropriate by the RP Department (see the RadCon Manual [pdf] for more details).

Radioactive Material Management Areas

A radioactive material management area (RMMA) is an area where the potential exists for radioactive contamination due to the presence of un-encapsulated or unconfined radioactive material, or exposure of material to beams of sub-atomic particles capable of causing radioactivation. Not all material in an RMMA will be labeled as radioactive, as non-radioactive items can become activated or contaminated while in an RMMA. Therefore, all potentially radioactive material must be surveyed by an RP health physics technician (HPT) or a qualified operator prior to removal from an RMMA. Any RMMA that is contaminated or has the potential for contamination will be posted as a contamination area. All accelerator housings are RMMAs.

Radiological Postings

All areas containing radiation hazards or having the potential to contain radiation hazards will be posted with the appropriate signs (see Radiological Safety: Radiological Posting and Signs [pdf]).

Regulations in 10 CFR 835 define the following radiological posting requirements. Any posting must:

• Be clear, legible, conspicuously posted, and may include radiological protection instructions
• Contain the standard radiation symbol colored magenta or black on a yellow background, with black or magenta lettering
• Be used to alert personnel to the presence of radiation and radioactive materials, and to aid them in minimizing exposures and preventing the spread of contamination
• Be kept up to date (by RP)

Personal Protective Equipment

PPE is equipment that is used to reduce employee exposure to hazards when engineering and administrative controls are not feasible or effective in reducing these exposures to acceptable levels. Examples of PPE for radiological protection at SLAC include gloves, booties, and other protective clothing.

Personnel Dosimetry and Dose Records / Reporting (Section 5.2.4)

A personnel whole-body dosimeter is required for each individual who will be entering an RCA or radiological area if there is a potential of 100 mrem TEDE in a year, or who will be handling radioactive materials if a potential of 100 mrem TEDE in a year is likely.

Any individual who needs a personnel dosimeter must complete the required training and fill out the SLAC Dosimeter/ID Request Form [pdf] and then obtain the dosimeter from the SLAC Security Office or other pre-designated distribution point authorized by the RP Department, such as the SSRL User Office.

Dosimeters need to be returned promptly to the RP Department at the end of the monitoring period. For detailed instructions for using a personnel dosimeter, see Radiological Safety: Personnel Dosimeter Use Requirements. [pdf]

The RP Department dosimetry program is responsible for providing radiation dose monitoring services and reporting dose information to dosimeter users. [pdf]

Individual Dose Reporting

Radiation dose information is available to the individual to whom the dosimeter was assigned. The frequency of dose reporting is based on the type of dosimeter worn. See Section 5.3 for details on dosimeter types.

Visitor / Temporary Dosimeter Reporting

Visitors, users, and subcontractors holding visitor/temporary dosimeters receive reports of non-zero radiation doses typically within 30 days of the dose determination, but no later than 90 days after the end of the visit. Dose reports to these individuals are also provided upon request.

GERT Dosimeter Reporting

Users of a GERT (annual exchange) dosimeter are provided a report of their annual dose upon request.

RWT Dosimeter Reporting

Users of an RWT (quarterly exchange) dosimeter are provided an annual report of their doses.

Dose History Reporting

Dose history reports contain all radiation dose information from the dosimeter during the user's stay at SLAC. The RP dosimetry program staff will issue dose history reports to departing SLAC employees upon written request.

Dosimeter User Request to Release Records

Dosimeter users (and former dosimeter users) may authorize the release of radiation dose information by submitting a request in writing to the dosimetry program staff. The request must contain the following items:

• Name of the dosimeter user
• Current telephone number and email address of the dosimeter user
• The name and address of the person or group to whom the records may be released

Policy for Pregnant / Possibly Pregnant Individuals

Any worker who is pregnant assumes the sole and fundamental responsibility whether to declare formally her pregnancy in writing and consequently become subject to lower prenatal dose limit and restrictions. (See Radiological Safety: Pregnant Worker Requirements [pdf] for more details.)

Radioactive Material and Radioactive Waste Handling (Section 5.2.5)

Transporting Radioactive Material within SLAC

Use of personal vehicles to transport radioactive material is prohibited. When needed, transport of radioactive materials must be conducted using SLAC vehicles and appropriate containers and equipment. Prior to transport, the individual who has ownership or responsibility for the radioactive material is responsible for contacting RP to ensure the radioactive materials are properly identified, packaged, and labeled.

Containers must be secured to prevent sliding or shifting of contents or the packages themselves during transport. Transporters of radioactive materials shall ensure the destination of the radioactive material is properly notified to receive the radioactive material.

For more detailed information on transporting radioactive material at SLAC or off site, see the RadCon Manual [pdf] and the Radioactive Waste Manual [pdf].

Managing Radioactive Waste

The Radioactive Waste Management Group of the RP Department provides radioactive waste processing services for radioactive waste generators. RP accepts, stores, processes, and prepares radioactive waste and/or mixed waste for shipment off-site to licensed/permitted treatment and disposal facilities.

Radioactive waste and mixed waste generators are responsible for the following tasks:

• Waste minimization
• Waste segregation, according to waste type (mixed versus radioactive only), and by material composition (concrete, metal, wire/cable). Segregation in this manner reduces both disposal and handling costs.
• Waste characterization, including chemical composition and physical state and composition.
• Packaging, marking, and labeling the waste in accordance with the requirements of Chapter 5 of the Radioactive Waste Manual [pdf]
• Completing a Radioactive Material Declaration Form [pdf], which certifies the waste meets the waste acceptance criteria of Chapter 5 of the Radioactive Waste Manual

For more detailed information on managing radioactive waste, consult the Radioactive Waste Manual.

Radioactive Sealed Source Management

Radioactive sealed sources typically are used at SLAC to calibrate instruments and for experimental work. A sealed source consists of radioactive material that is either fixed between layers of non-radioactive material or fixed to a non-radioactive surface and contained in a closed capsule. Sealed sources are categorized as either accountable or exempt (exempt sources are also known as non-accountable sources).

To obtain a sealed source at SLAC, individuals can borrow one from the RP Department Field Operations Group or from a radioactive source custodian.

Personnel using a sealed source are identified as either a custodian or a user. In many cases, the custodian and user is the same individual. For temporary accountability purposes, a user could be a user group.

A custodian is an individual or group directly responsible for the safe and positive controls of one or more sealed sources. A custodian may temporarily issue a sealed source to another user as long as the requirements below are met. Custodians will be trained in these policies prior to receiving custody of sealed sources, and must be retrained on these policies every two years.

Users typically have sealed sources in their possession for no more than a few days. Users are prohibited from transferring sealed sources to other personnel. Only custodians can issue sealed sources. Users will be briefed on the sealed source policies by custodians prior to taking possession of any sealed source, and at least once every two years while in possession of the sealed source.

See RP Department Radioactive Sealed Source Procedure [pdf] and the RadCon Manual [pdf] for further discussion on control requirements for sealed sources.

Storage of Radioactive Material

The storage of radioactive materials within SLAC is subject to controls and will be coordinated with the RP Department.

Material determined to be radioactive must be stored within a radiologically controlled area (RCA) or radioactive material area (RMA). In most cases, all radioactive material is identified with a radioactive label except if located in accelerator housings or a RMA, where all material is considered radioactive and must be surveyed upon removal.

Decommissioning Activities

Decommissioning activities that may involve potentially radioactive materials are subject to case-by-case evaluation by the RP Department.

Radiological Facility Classification of SLAC (Section 5.2.6)

The DOE Office of Science has classified each radiological portion of SLAC as a radiological facility per the radionuclide quantity limits for such classification as defined in DOE Standard 1027. [pdf]

It is a SLAC goal to remain classified as no higher than a radiological facility in all locations, to allow SLAC optimal ease of access throughout the site. Preservation of this classification is managed by the RP Department. RP controls onsite quantities of radionuclides such that research support is optimized while keeping SLAC within the limits of a radiological facility. Before bringing any radioactive material (including radioactive sources) to SLAC, RP must be contacted to ensure quantities will not cause SLAC to exceed the allowance for a radiological facility.

continue to Training (5.3)