| (9) The applicant shall describe the inspection and maintenance checks, including the frequency of the checks required by subsection (x) of this section. (f) Start of construction. The applicant may not begin construction of a new irradiator prior to the submission to the agency of both an application for a license for the irradiator and the fee required by §289.204 of this title. As used in this section, the term "construction" includes the construction of any portion of the permanent irradiator structure on the site but does not include: engineering and design work; purchase of a site; site surveys or soil testing; site preparation; site excavation; construction of warehouse or auxiliary structures; and other similar tasks. Any construction activities undertaken prior to the issuance of a license are entirely at the risk of the applicant and have no bearing on the issuance of a license with respect to the requirements of the Texas Radiation Control Act (Act), rules, and orders issued in accordance with the Act. (g) Applications for exemptions. Any applications for a license or for amendment of a license authorizing use of a teletherapy-type unit for irradiation of materials or objects may include proposed alternatives for the requirements of this section. The agency will approve the proposed alternatives if the applicant provides adequate rationale for the proposed alternatives and demonstrates that they are likely to provide an adequate level of safety for workers and the public. (h) Performance criteria for sealed sources. (1) Cesium-137 shall not be used in any irradiator other than a Category I self-contained, dry-source irradiator as defined in subsection (c) of this section. (2) Sealed sources. Sealed sources installed after August 1, 1996, shall meet the following requirements: (A) have been evaluated in accordance with §289.252(v) of this title; (B) be doubly encapsulated; (C) use radioactive material that is as nondispersible as practical and that is as insoluble as practical if the source is used in a wet-source-storage or wet-source-change irradiator; (D) 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; and (E) have been leak tested and found leak-free in prototype testing of the sealed source after each of the tests described in paragraphs (3) - (8) of this subsection. (3) Temperature. The test source shall be held at -40 degrees Celsius for 20 minutes, 600 degrees Celsius for one hour, and then be subjected to thermal shock test with a temperature drop from 600 degrees Celsius to 20 degrees Celsius within 15 seconds. (4) Pressure. The test source shall be twice subjected for at least five minutes to an external pressure (absolute) of 2 million newtons per square meter. (5) Impact. A 2-kilogram steel weight, 2.5 centimeters in diameter, shall be dropped from a height of 1 m onto the test source. (6) Vibration. The test source shall be subjected three times for ten minutes each to vibrations sweeping from 25 hertz to 500 hertz with a peak amplitude of five times the acceleration of gravity. In addition, each test source shall be vibrated for 30 minutes at each resonant frequency found. (7) Puncture. A 50-gram weight and pin, 0.3-centimeter pin diameter, shall be dropped from a height of 1 m onto the test source. (8) 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 2,000 newtons at its center equidistant from two support cylinders, the distance between which is 10 times the minimum cross-sectional dimension of the source. (i) Access control requirements in addition to the requirements of §289.202(u) of this title. (1) Each entrance to a radiation room at a panoramic irradiator shall have a door or other physical barrier to prevent inadvertent entry of personnel if 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 not be possible 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 doors and barriers shall not prevent any individual in the radiation room from leaving. (2) In addition, 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 also activate a visible and audible alarm to make the individual entering the room aware of the hazard. The alarm shall also make at least one other individual who is onsite aware of the entry. That individual shall be trained on how to respond to the alarm and be prepared to promptly render or summon assistance. (3) 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 paragraph (2) of this subsection. The monitor may be located in the entrance (normally referred to as the maze) but not in the direct radiation beam. (4) 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 individuals enough time to leave the room and to operate the control described in paragraph (5) of this subsection before the sources leave the shielded position. (5) Each radiation room at a panoramic irradiator shall have a clearly visible and readily accessible control that allows an individual in the room to return the sources to their fully shielded position. (6) 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. (7) 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." Panoramic irradiators shall also have a sign stating "CAUTION (or DANGER), HIGH RADIATION AREA," as defined in §289.201(b) of this title, or "GRAVE DANGER, VERY HIGH RADIATION AREA," as defined in §289.201(b) of this title, whichever is applicable, but the sign may be removed, covered, or otherwise made inoperative when the sources are fully shielded. (8) If the radiation room of a panoramic irradiator has roof plugs or other movable shielding, it shall not be possible to 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. (9) Underwater irradiators shall have a personnel access barrier around the pool that shall be locked to prevent access when the irradiator is not attended. Only operators and facility management may have access to keys to 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 an individual (not necessarily onsite) who is prepared to respond or summon assistance. (j) Shielding. (1) The radiation dose rate in areas that are normally occupied during operation of a panoramic irradiator may not exceed 2 millirems (mrem) (0.02 millisievert (mSv)) per hour at any location 30 centimeters (cm) 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 (cm2 ) having no linear dimension greater than 20 cm. Areas where the radiation dose rate exceeds 2 mrem (0.02 mSv) per hour shall be locked, roped off, or posted. (2) The radiation dose at 30 cm over the edge of the pool of a pool irradiator may not exceed 2 mrem (0.02 mSv) per hour when the sources are in the fully shielded position. Cont'd... |
