DHS 157.72(4)(b)4.4. The probable cause and an assessment of failure in the licensee’s equipment, procedures or training that contributed to the excessive readings if an error occurred in the licensee’s breakthrough determination. DHS 157.72 NoteNote: A written report may be submitted to: Department of Health Services, Radiation Protection Section, P.O. Box 2659, Madison WI 53701-2659
DHS 157.72 HistoryHistory: CR 01-108: cr. Register July 2002 No. 559, eff. — see Note at the start of the chapter; CR 06-021: r. and recr. (1) (a) 3., (h) and (2) Register October 2006 No. 610, eff. 11-1-06; CR 16-078: am. (1) (a) 1. (intro.) Register January 2018 No. 745, eff. 2-1-18; CR 22-015: am. (1) (a) (intro.), 3., cr. (1) (am), am. (2) (f) 1. b., cr. (4) Register June 2023 No. 810, eff. 7-1-23. DHS 157.73DHS 157.73 Radiation safety requirements. DHS 157.73(1)(a)(a) A sealed source installed in an irradiator shall meet all of the following requirements: DHS 157.73(1)(a)3.3. Use radioactive material that is as nondispersible and insoluble as practical if the source is used in a wet-source-storage or wet-source-change irradiator. DHS 157.73(1)(a)4.4. Be encapsulated in a material resistant to general corrosion and to localized corrosion such as 316L stainless steel or other material with equivalent resistance if the sources are for use in irradiator pools. DHS 157.73(1)(a)5.5. In prototype testing of the sealed source, be leak tested and found leak-free after each of the tests in par. (b). DHS 157.73(1)(b)(b) A sealed source used in an irradiator shall be subjected to all of the following tests prior to use: DHS 157.73(1)(b)1.1. ‘Temperature.’ The test source shall be held at -40°C for 20 minutes, 600°C for one hour, and then be immediately subjected to thermal shock test with a temperature drop from 600°C to 20°C within 15 seconds. DHS 157.73(1)(b)2.2. ‘Pressure.’ The test source shall be twice subjected for at least 5 minutes to an absolute external pressure of 2 million newtons per square meter. DHS 157.73(1)(b)3.3. ‘Impact.’ A 2 kilogram steel weight, 2.5 centimeters in diameter, shall be dropped from a height of one meter on to the test source. DHS 157.73(1)(b)4.4. ‘Vibration.’ The test source shall be subjected 3 times for 10 minutes each to vibrations sweeping from 25 hertz to 500 hertz with a peak amplitude of 5 times the acceleration of gravity. In addition, each test source shall be vibrated for 30 minutes at each resonant frequency found. DHS 157.73(1)(b)5.5. ‘Puncture.’ A 50 gram weight and pin, 0.3 centimeter pin diameter, shall be dropped from a height of one meter on to the test source. DHS 157.73(1)(b)6.6. ‘Bend.’ If the length of the source is more than 15 times larger than the minimum cross-sectional dimension, the test source shall be subjected to a force of 2000 newtons at its center equidistant from 2 support cylinders, the distance between which is 10 times the minimum cross-sectional dimension of the source. DHS 157.73(2)(a)(a) Each entrance to a radiation room at a panoramic irradiator shall have a door or other physical barrier to prevent inadvertent entry of personnel when the sources are not in the shielded position. Product conveyor systems may serve as barriers as long as they reliably and consistently function as a barrier. It shall be impossible to move the sources out of their shielded position if the door or barrier is open. Opening the door or barrier while the sources are exposed shall cause the sources to return promptly to the shielded position. The personnel entrance door or barrier shall have a lock that is operated by the same key used to move the sources. The control panel lock shall be designed so that the key cannot be removed unless the sources have been returned to the shielded position. The doors and barriers may not prevent any person in the radiation room from leaving. DHS 157.73(2)(b)(b) Each entrance to a radiation room at a panoramic irradiator shall have an independent backup access control to detect personnel entry while the sources are exposed. Detection of entry while the sources are exposed shall cause the sources to return to their fully shielded position and shall activate a visible and audible alarm to make the person entering the room aware of the hazard. The alarm shall also alert at least one other person who is on-site of the entry. The person alerted shall be trained on how to respond to the alarm and prepared to promptly render or summon assistance. DHS 157.73(2)(c)(c) A radiation monitor shall be provided to detect the presence of high radiation levels in the radiation room of a panoramic irradiator before personnel entry. The monitor shall be integrated with personnel access door locks to prevent room access when radiation levels are high. Attempted personnel entry while the monitor measures high radiation levels shall activate the alarm described in par. (b). The monitor may be located in the entrance, normally referred to as the maze, but not in the direct radiation beam. DHS 157.73(2)(d)(d) Before the sources move from their shielded position in a panoramic irradiator, the source control shall automatically activate conspicuous visible and audible alarms to alert people in the radiation room that the sources will be moved from their shielded position. The alarms shall give persons enough time to leave the room before the sources leave the shielded position. DHS 157.73(2)(e)(e) Each radiation room of a panoramic irradiator shall have a clearly visible and readily accessible control that allows a person in the room to make the sources return to their fully shielded position. DHS 157.73(2)(f)(f) Each radiation room of a panoramic irradiator shall contain a control that prevents the sources from moving from the shielded position unless the control has been activated and the door or barrier to the radiation room has been closed within a preset time after activation of the control. DHS 157.73(2)(g)(g) Each entrance to the radiation room of a panoramic irradiator and each entrance to the area within the personnel access barrier of an underwater irradiator shall have a sign bearing the radiation symbol and the words, “Caution (or danger), radioactive material.” A panoramic irradiator shall have a sign stating “Grave (or Extreme) danger, very high radiation area,” but the sign may be removed, covered or otherwise made inoperative when the sources are fully shielded. DHS 157.73(2)(h)(h) If the radiation room of a panoramic irradiator has roof plugs or movable shielding, no person may operate the irradiator unless the shielding is in its proper location. The requirement may be met by interlocks that prevent operation if shielding is not placed properly or by an operating procedure requiring inspection of shielding before operating. DHS 157.73(2)(i)(i) An underwater irradiator shall have a personnel access barrier around the pool that shall be locked to prevent access when the irradiator is not attended. Only operators or facility management may have access to keys that operate the personnel access barrier. There shall be an intrusion alarm to detect unauthorized entry when the personnel access barrier is locked. Activation of the intrusion alarm shall alert a person who is not necessarily on-site but who is prepared to respond or summon assistance. DHS 157.73(3)(a)(a) The radiation dose rate in areas that are normally occupied during operation of a panoramic irradiator may not exceed 0.02 millisievert (2 mrem) per hour at any location 30 centimeters or more from the wall of the room when the sources are exposed. The dose rate shall be averaged over an area not to exceed 100 square centimeters having no linear dimension greater than 20 centimeters. Any area where the radiation dose rate exceeds 0.02 millisievert (2 mrem) per hour shall be locked, roped off or posted. DHS 157.73(3)(b)(b) The radiation dose at 30 centimeters over the edge of the pool of a pool irradiator may not exceed 0.02 millisievert (2 mrem) per hour when the sources are in the fully shielded position. DHS 157.73(3)(c)(c) The radiation dose rate at one meter from the shield of a dry-source-storage panoramic irradiator when the source is shielded may not exceed 0.02 millisievert (2 mrem) per hour and at 5 centimeters from the shield may not exceed 0.2 millisievert (20 mrem) per hour. DHS 157.73(4)(a)(a) The radiation room of a panoramic irradiator shall have heat and smoke detectors. The detectors shall activate an audible alarm. The alarm shall be capable of alerting a person who is prepared to summon assistance promptly. The sources shall automatically become fully shielded if a fire is detected. DHS 157.73(4)(b)(b) The radiation room of a panoramic irradiator shall be equipped with a fire extinguishing system capable of extinguishing a fire without the entry of personnel into the room. The system for the radiation room shall have a shut-off valve to control flooding into unrestricted areas. DHS 157.73(5)(a)(a) An irradiator with an automatic product conveyor system shall have a radiation monitor with an audible alarm located to detect loose radioactive sources that are carried toward the product exit. If the monitor detects a source, an alarm shall sound and product conveyors shall stop automatically. The alarm shall be capable of alerting a person in the facility who is prepared to summon assistance. An underwater irradiator in which the product moves within an enclosed stationary tube is exempt from the requirements of this paragraph. DHS 157.73(5)(b)(b) An underwater irradiator that is not in a shielded radiation room shall have a radiation monitor over the pool to detect abnormal radiation levels. The monitor shall have an audible alarm and a visible indicator at entrances to the personnel access barrier around the pool. The audible alarm may have a manual shut-off. The alarm shall be capable of alerting a person who is prepared to respond promptly. DHS 157.73(6)(a)(a) The mechanism that moves the sources of a panoramic irradiator shall require a key to actuate. Actuation of the mechanism shall cause an audible signal to indicate that the sources are leaving the shielded position. Only one key may be in use at any time, and only operators or facility management may possess it. The key shall be attached to a portable radiation survey meter by a chain or cable. The lock for source control shall be designed so that the key may not be removed if the sources are in an unshielded position. The door to the radiation room shall require the same key. DHS 157.73(6)(b)(b) The console of a panoramic irradiator shall have a source position indicator that indicates when the sources are in the fully shielded position, in transit and exposed. DHS 157.73(6)(c)(c) The control console of a panoramic irradiator shall have a control that promptly returns the sources to the shielded position. DHS 157.73(6)(d)(d) The function of each control for a panoramic irradiator shall be clearly marked. DHS 157.73(7)(a)1.1. Constructed with a water-tight stainless steel liner or a liner metallurgically compatible with other components in the pool. DHS 157.73(7)(a)2.2. Constructed so that there is a low likelihood of substantial leakage and with a surface designed to facilitate decontamination. DHS 157.73(7)(b)(b) A licensee shall have a method to safely store the sources during repairs of the pool. DHS 157.73(7)(c)(c) An irradiator pool shall have no outlets more than 0.5 meter below the normal low water level that may allow water to drain out of the pool. Pipes that have intakes more than 0.5 meter below the normal low water level and that may act as siphons shall have siphon breakers to prevent the siphoning of pool water. DHS 157.73(7)(d)(d) A method shall be available to replenish water losses from the pool. DHS 157.73(7)(e)(e) A visible indicator shall be provided in a clearly observable location to indicate if the pool water level is below the normal low water level or above the normal high water level. DHS 157.73(7)(f)(f) An irradiator pool shall be equipped with a purification system designed to be capable of maintaining the water during normal operation at a conductivity of 20 microsiemens per centimeter or less and with a clarity so that the sources are clearly visible. DHS 157.73(7)(g)(g) A physical barrier, such as a railing or cover, shall be used around or over irradiator pools during normal operation to prevent personnel from accidentally falling into the pool. The barrier may be removed during maintenance, inspection and service operations. DHS 157.73(7)(h)(h) If long-handled tools or poles are used in an irradiator pool, the radiation dose rate to the operator at the handling areas of the tools may not exceed 0.02 millisievert (2 mrem) per hour. DHS 157.73(8)(8) Source rack protection. If the product to be irradiated moves on a product conveyor system, the source rack and the mechanism that moves the rack shall be protected by a carrier or guides to prevent products and product carriers from hitting or touching the rack or mechanism. DHS 157.73(9)(a)(a) If electrical power at a panoramic irradiator is lost for longer than 10 seconds, the sources shall automatically return to the shielded position. DHS 157.73(9)(b)(b) The lock on the door of the radiation room of a panoramic irradiator shall remain locked in the event of a power failure. DHS 157.73(9)(c)(c) During a power failure, the area of any irradiator where sources are located may be entered only when using an operable and calibrated radiation survey meter. DHS 157.73(10)(10) Design requirements. An irradiator shall meet all of the following design requirements: DHS 157.73(10)(a)(a) Shielding. For a panoramic irradiator, a licensee shall design shielding walls to meet generally accepted building code requirements for reinforced concrete and design the walls, wall penetrations, and entranceways to meet the radiation shielding requirements of sub. (3). If the irradiator will use more than 2 x 1017 becquerels (5 million Ci) of activity, a licensee shall evaluate the effects of heating of the shielding walls by the irradiator sources. DHS 157.73(10)(b)(b) Foundations. For a panoramic irradiator, a licensee shall design the foundation, with consideration given to soil characteristics, to ensure that the foundation is adequate to support the weight of the facility shield walls. DHS 157.73(10)(c)(c) Pool integrity. For a pool irradiator, a licensee shall design the pool to ensure all of the following: DHS 157.73(10)(c)2.2. That the pool is strong enough to bear the weight of the pool water and shipping casks. DHS 157.73(10)(c)5.5. That metal components are metallurgically compatible with other components in the pool. DHS 157.73(10)(d)(d) Water handling system. For a pool irradiator, a licensee shall verify that the design of the water purification system is adequate to meet the requirements of sub. (7) (f). The system shall be designed so that water leaking from the system does not drain to unrestricted areas without being monitored. DHS 157.73(10)(e)(e) Radiation monitors. For all irradiators, a licensee shall evaluate the location and sensitivity of the radiation monitor to detect sources carried by the product conveyor system as required by sub. (5) (a). A licensee shall verify that the product conveyor is designed to stop before a source on the product conveyor would cause a radiation overexposure to any person. For a pool irradiator, if the licensee uses radiation monitors to detect contamination under sub. (16) (b), the licensee shall verify that the design of radiation monitoring systems to detect pool contamination includes sensitive detectors located close to where contamination is likely to concentrate. DHS 157.73(10)(f)(f) Source rack. For a pool irradiator, a licensee shall verify that there are no crevices on the source or between the source and source holder that would promote corrosion on a critical area of the source. For a panoramic irradiator, a licensee shall determine that source rack drops due to loss of power will not damage the source rack and that source rack drops due to failure of cables, or alternate means of support, will not cause loss of integrity of sealed sources. For a panoramic irradiator, a licensee shall review the design of the mechanism that moves the sources to ensure that the likelihood of a stuck source is low and that, if the rack sticks, a means exists to free the rack with minimal risk to personnel. DHS 157.73(10)(g)(g) Access control. For a panoramic irradiator, a licensee shall verify from the design and logic diagram that the access control system meets the requirements of sub. (2). DHS 157.73(10)(h)(h) Fire protection. For a panoramic irradiator, a licensee shall verify that the number, locations, and spacing of the smoke and heat detectors are appropriate to detect fires and that the detectors are protected from mechanical and radiation damage. A licensee shall verify that the design of the fire extinguishing system provides the necessary discharge patterns, densities, and flow characteristics for complete coverage of the radiation room and that the system is protected from mechanical and radiation damage. DHS 157.73(10)(i)(i) Source return. For a panoramic irradiator, a licensee shall verify that the source rack will automatically return to the fully shielded position if power is lost for more than 10 seconds. DHS 157.73(10)(j)(j) Seismic. For a panoramic irradiator to be built in seismic areas where the probability of a horizontal acceleration in rock of more than 0.3 times the acceleration of gravity in 250 years is greater than 10%, a licensee shall design the reinforced concrete radiation shields to retain their integrity in the event of an earthquake by designing the irradiator to the seismic requirements of local building codes. DHS 157.73(10)(k)(k) Wiring. For a panoramic irradiator, a licensee shall verify that electrical wiring and electrical equipment in the radiation room are selected to minimize failures due to prolonged exposure to radiation. DHS 157.73(11)(11) Construction monitoring and acceptance testing. An irradiator shall meet all of the following requirements prior to loading sources: DHS 157.73(11)(a)(a) Shielding. For a panoramic irradiator, a licensee shall monitor the construction of the shielding to verify that its construction meets design specifications and local building code requirements for reinforced concrete. DHS 157.73(11)(b)(b) Foundations. For a panoramic irradiator, a licensee shall monitor the construction of the foundations to verify that their construction meets design specifications. DHS 157.73(11)(c)(c) Pool integrity. For a pool irradiator, a licensee shall verify that the pool meets design specifications and shall test the structural integrity of the pool and its ability to hold water. A licensee shall verify that outlets and pipes meet the requirements of sub. (7) (c). DHS 157.73(11)(d)(d) Water handling system. For a pool irradiator, a licensee shall verify that the water purification system, the conductivity meter, and the water level indicators operate properly. DHS 157.73(11)(e)(e) Radiation monitors. For all irradiators, a licensee shall verify the proper operation of the radiation monitor to detect sources carried on the product conveyor system and the related alarms and interlocks required by sub. (5) (a). For a pool irradiator, a licensee shall verify the proper operation of the radiation monitors and the related alarm, if used, to meet sub. (16) (b). For an underwater irradiator, a licensee shall verify the proper operation of the over-the-pool monitor, alarms, and interlocks required by sub. (5) (b). DHS 157.73(11)(f)(f) Source rack. For a panoramic irradiator, a licensee shall test the movement of the source racks for proper operation prior to source loading. The testing shall include source rack lowering due to simulated loss of power. For all irradiators with a product conveyor system, a licensee shall observe and test the operation of the conveyor system to assure that the requirements in sub. (8) are met for protection of the source rack and the mechanism that moves the rack. The testing shall include tests of any limit switches and interlocks used to protect the source rack and mechanism that moves that rack from moving product carriers. DHS 157.73(11)(g)(g) Access control. For a panoramic irradiator, a licensee shall test the completed access control system to assure that the control system functions as designed and that all alarms, controls, and interlocks work properly. DHS 157.73(11)(h)(h) Fire protection. For a panoramic irradiator, a licensee shall test the ability of the heat and smoke detectors to detect a fire, to activate alarms, and to cause the source rack to automatically become fully shielded. A licensee shall test the operability of the fire extinguishing system. DHS 157.73(11)(i)(i) Source return. For a panoramic irradiator, the licensee shall demonstrate that the source racks may be returned to their fully shielded positions without power. DHS 157.73(11)(j)(j) Computer systems. For a panoramic irradiator that uses a computer system to control the access control system, a licensee shall verify that the access control system will operate properly if power is lost and shall verify that the computer has security features that prevent an irradiator operator from commanding the computer to override the access control system when the system is required to be operable.
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Department of Health Services (DHS)
Chs. DHS 110-199; Health
administrativecode/DHS 157.73(2)(i)
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