Handbook of Federal Regulations Applying to Transportation of Radioactive Materials

Limitation of the radiation from either end of the car to 10 mr./hr. at 5 feet may be achieved either by spacing or by the use of shielding. The term "no loose material" is not defined by the ICC. The usage here and in paragraph 74.532 (j) implies that "loose material" means amounts of material which may be introduced as a result of spillage, either within the car or onto the containers or equipment which are brought into the car. The level of gamma radiation which may exist in the car after unloading is specified in section 73.395.

73.393. Packing and shielding:

(a) Radioactive materials that present special hazards due to their tendency to remain fixed in the human body for long periods of time (i. e., radium, plutonium, and radioactive strontium, etc.) must, in addition to the packaging hereinafter prescribed, be packed in inside metal containers specification 2R, or other container approved by the Bureau of Explosives.

Specifications for 2R containers are given in Section 78.34 of the ICC Regulations (not excerpted in this Handbook). The requirement that packages containing radium, plutonium, etc., be packed in inside containers of this specification is not considered to apply to cases in which these radioisotopes occur in low activity materials as discussed in 73.392 (c) or as impurities in other radioactive materials.

(b) All radioactive materials must be so packed and shielded that the degree of fogging of undeveloped film under conditions normally incident to transportation (24 hours at 15 feet from the package) will not exceed that produced by 11.5 milliroentgens of penetrating gamma rays of radium filtered by 1/2 inch of lead.

The quantity of gamma radiation referred to, 11.5 milliroentgens, is that measured after filtration by the lead. Photographic emulsions are more sensitive to gamma radiations of quantum energies less than about 0.15 Mev than to harder or more penetrating gamma radiation of higher quantum energies. Filtration of radium gamma radiation by this thickness of lead removes practically all of the quanta with energies as low as 0.15 Mev and provides an arbitrary standard of photographic effectiveness with which other gamma radiation may be compared.

For cases in which the gamma emission from the radioactive materials within the package contains a strong component of quantum energy higher than about 0.2 or 0.3 Mev, and a substantial amount of lead shielding is used in bringing the radiation from the package down to prescribed limits, the gamma radiation emitted from the package may be considered to have the same photographic effectiveness per milliroentgen of exposure as gamma radiation from radium filtered by 1/2 inch of lead. Ordinarily, for Group I packages, this is the case.

The following table, adapted from Table IX, p. 48, NRC Publication 205 (cited in Chapter I of this Handbook), gives the relative sensitivity of photographic emulsions to gamma radiations of different quantum energies below 0.15 Mev as compared to sensitivity to radium radiation filtered as specified above:

Quantum energy.
Relative sensitivity_

1111

0.14 0.12 0.09 0.075 0.06 0.045 0.03
1.2 2.3 4.9 8.6 14 21
24

As an example of the application of these values to paragraph 73.393(b), if a package emits gamma radiation of which the effective quantum energy is 0.09 Mev, the maximum gamma radiation permitted at 15 feet from the package is 11.5/4.9 milliroentgens per 24 hours. For a more complete discussion, the reader is referred to NRC Publication 205, pp. 15–24 and 48-49.

(c) The design and preparation of the package must be such that there will be no significant radioactive surface contamination of any part of the container.

(d) The smallest dimension of any outside shipping container for radioactive materials must be not less than 4 inches.

(e) All outside shipping containers must be of such design that the gamma radiation will not exceed 200 milliroentgens per hour or equivalent at any point of readily accessible surface. Containers must be equipped with handles and protective devices when necessary in order to satisfy this requirement.

(f) The outside shipping container for any radioactive material, unless specifically exempt by 73.392 or unless approved by the Bureau of Explosives, shall be as follows: (1) Spec. 15A or 15B (78.168 or 78.169 of this chapter). Wooden boxes. Authorized for not more than 2,700 millicuries; (2) Spec. 12B (78.205 of this chapter). Fibreboard boxes. Authorized for not more than 2,700 millicuries; (3) Spec. 21A or 21B (78.222 or 78.223 of this chapter). Fibre drums. Authorized for not more than 2,700 millicuries; (4) Spec. 6A, 6B, or 6C. 17C or 17H (single-trip) (78.97, 78.98, 78.99, 78.115 or 78.118 of this chapter). Metal barrels or drums. Authorized for not more than 2,700 millicuries; (5) Spec. 55 (78.250 of this chapter). Metal-encased, lead-shielded containers. Authorized for not more than 300 curies (see 73.391). Containers must be equipped with a seal.*

Specifications for these containers are given in Part 78 of ICC regulations. These specifications are not excerpted in this Handbook.*

(g) Radioactive materials Group I, liquid, solid, or gaseous, must be packed in suitable inside containers completely surrounded by a shield of lead or other suitable material of such thickness that at any time during transportation the gamma radiation at one meter

*Revised May 3, 1955.

(39.3 inches) from any point on the radioactive source will not exceed 10 milliroentgens per hour. The shield must be so designed that it will not open or break under conditions incident to transportation. The minimum shielding must be sufficient to prevent the escape of any primary corpuscular radiation to the exterior of the outside shipping container.

". . . at one meter from any point on the radioactive source is interpreted to mean "at one meter from the nearest point on the source."

(h) Radioactive materials Group II, liquid, solid, or gaseous, must be packed in suitable inside containers, completely shielded so that at any time during transportation the radiation measured at right angles to any point on the long axis of the shipping container will not exceed the limits specified in subparagraphs (1) to (4) of this paragraph. The shielding must be designed so as to maintain its efficiency under conditions normally incident to transportation and must provide personnel protection against fast or slow neutrons and all other ionizing radiation originating in the radioactive materials or any part of the aggregate constituting the complete package.

(1) Gamma radiation of 10 mrhm.

(2) Electrically charged corpuscular radiation which is the physical equivalent (see note 1 of this paragraph) of 10 mrhm. of gamma radiation.

(3) Neutron radiation which is the physical equivalent (see note 1 of this paragraph) of 2 mrhm. of gamma radiation.

(4) If more than one of the types of radiation named in subparagraphs (1), (2), and/or (3) of this paragraph is present the radiation of each type must be reduced by shielding so that the total does not exceed the equivalent of subparagraphs (1), (2), or (3) of this paragraph.

NOTE 1.-For purposes of Parts 71-78 the "physical equivalent" of a roentgen is that amount of radiation that would be absorbed in tissue to the extent of 100 ergs per gram (mrhm. is an abbreviation for milli roentgens per hour at 1 meter (39.3 inches)).*

(i) Liquid radioactive materials Groups I, II or III must, in addition, be packed in tight glass, earthenware, or other suitable inside containers. The inside containers must be surrounded on all sides and within the shield by an absorbent material sufficient to absorb the entire liquid contents and of such nature that its efficiency will not be impaired by chemical reaction with the contents. If the container is packed in a metal container specification 2R or other container approved by the Bureau of Explosives, the absorbent cushioning is not required.

(j) Radioactive materials Group III, liquid, solid or gaseous, must be packed in suitable inside containers completely wrapped and/or shielded with such material as will prevent the escape of primary corpuscular radiation to the exterior of the shipping container, and secondary radiation at the surface of the container must not exceed 10 milliroentgens per 24 hours, at any time during transportation.

(k) In determining compliance with requirements of paragraphs (e), (g), (h), and (j) of this section measurements of radiation must be made with a Landsverk-Wollan Electrometer Model L-100 or equally efficient standardized meter.

Acceptable instruments for measuring the gamma radiation from packages include the gamma survey meters listed in the SIC series of the AEC Instruments Catalog. Acceptable instruments for the measurement of fast neutron emission include the fast neutron instruments listed in the SIC and SPC Series of the AEC Instruments Catalog.

73.394. Radioactive materials labels:

(a) Each outside container of radioactive material Group I or II, unless exempt by 73.392 of this part, must be labeled with a properly executed label as described in 73.414 (a) of this part.

A properly executed label for Group I or Group II requires the name of the principal radioisotope or radioelement, the activity of the contents (measured in curies or in disintegrations per second), the number of units of radiation from the package, and the name of the shipper. If the nature of the radioactive content cannot be appropriately designated by entering a single radioisotope or radioelement, it may be described as "Chemical NOS" (i. e., chemical, not otherwise specified). See comments on paragraph 73.392 (a) (2) for relations between activity and weight of radium, uranium, and thorium.

The number of radiation units is a measure of the gamma radiation from the package as defined in the Note of 73.414 (a), not of the quantity of radioactive material in the package. For cases in which the quantum energy of the radiation is less than 0.15 Mev, see the discussion following paragraph 73.393 (b) above. The actual number of radiation units should be entered on the label. Use of such statements as "less than 10" is unacceptable since this may lead to unnecessary restrictions if several packages occur in the same car, truck, or terminal. (See 75.655 (j) (3) and 77.841 (d) (2) for regulations limiting transportation by one car or vehicle and storage in one place to 40 units.)

(b) Each outside container of radioactive material Group III must unless exempt by 73.392 of this part, be labeled with a properly executed label as described in 73.414 (b) of this part.

73.395. Cleaning Cars and Vehicles:

(a) Any box car or motor vehicle which, after use for the transportation of radioactive materials in carload or truckload lots, is contaminated with such materials to the extent that a survey of the interior surface shows that the beta-gamma radiation is greater than 10 milliroentgens physical equivalent in 24 hours or that the average alpha contamination is greater than 500 disintegrations per minute per 100 square centimeters shall be thoroughly cleaned in such a manner that a resurvey of the interior surface shows the contamination to be below these levels. A certificate to that effect must be furnished to the local agent of the carrier or to the driver of the motor vehicle. Cars and motor vehicles which are used solely for the transportation of radioactive materials are exempt from the provisions of this section."

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Handbook of Federal Regulations Applying to Transportation of Radioactive ...