Section 31.104 of Title 10, Code of Federal Regulations, Part 31, requires that radiation survey instruments used in radiographic operations be calibrated at intervals not to exceed 3 months and after each instrument servicing. It should be noted that the small check source which is incorporated into several models of survey instruments is not acceptable for calibration purposes. To properly calibrate a survey instrument its response must be checked at two or more points on each scale. This cannot normally be accomplished with a "built-in" source. In addition, the instrument should be calibrated against gamma radiation.

When byproduct material is used to calibrate survey instruments the individual performing the calibration must be specifically authorized by the Commission. An application for a license to perform this service must contain adequate information on the following:

1. The type and strength of the sealed source to be used.

2. A description of the facilities to be used. 3. A copy of the calibration procedures.

4. The name and pertinent experience of the individual who will use the byproduct material.

5. Calculations pertinent to the calibration procedure.

Under certain circumstances it may be practical to use a radiography source to calibrate survey instrumentation. However, if high-curiage radiography sources are employed it may be difficult to use these sources without elaborate facilities and procedures. The following may be used as a guide for preparing instrument calibration procedures:

1. Determine present activity of source. Normally, the source supplier furnishes a decay curve with each radiography source from which one may readily ascertain the present activity of the source. Likewise, the radiation output per curie from radioisotopes commonly used in radiography is readily available. These values are usually listed for distances of one foot or one meter from the source. When the source strength and radiation output at a specified distance per curie are known one can use this information to determine the radiation level at any desired distance from the source. The following formulas may be used to determine approximate radiation levels at one foot from the source.

For Iridium 192

Output at one foot (R/HR)=5.9 X source strength in curies.

For Cobalt 60

Output at one foot (R/HR)=14 X source strength in curies.

For Cesium 137

Output at one foot (R/HR)=3.3 X source strength in curies.

For Radium Output at one foot (R/HR)=9.0 X source strength in curies.

When the radiation output has been determined at one foot from a source (or any other known distance) the inverse square law for reduction of radiation intensity may be used to determine the intensity at any desired distance from the source. (In the calibration procedure it will be necessary to vary the radiation intensity to which the instrument is exposed.) The inverse square law states that radiation intensity from a point source varies inversely as the square of the distance from the source. This law is expressed in the following formula:

Where I is the radiation intensity at distance R1 from the source and I2 is the radiation intensity at distance R2, from the source. This formula shows that doubling the distance decreases intensity by a factor of four; increasing the distance by a factor of three reduces the radiation intensity to one-ninth of its value, etc.

2. Check each instrument at two or more points on each scale. If the instrument readings correspond to calculated values, within a range of plus or minus 20 percent, it can be considered to be properly calibrated. Minor adjustments can oftentimes be made which will bring the instrument within the desired range.

3. If the instrument cannot be adjusted in order for the readings to fall within the calculated range it should be returned to the manufacturer or a qualified instrument repair laboratory for repair and calibration.

4. A record of the last date of calibration must be maintained by the licensee.

The following list describes duties which may be performed by the licensee's management personnel. The individual(s) assigned these duties may bear the title of Radiation Safety Officer, Radiation Protection Officer or some similar designation. The list is not intended to be all inclusive nor should it be interpreted as a requirement that any one person assume all of the listed duties.

1. Serve as the licensee's liaison officer with the Atomic Energy Commission on license matters.

2. Maintain control of procurement and disposal of licensed byproduct material.

3. Develop and maintain up-to-date operating and emergency procedures.

4. Establish and maintain a personnel monitoring program.

5. Procure and maintain adequate radiation survey instruments.

6. Establish and conduct the training program for radiographers and radiographer's assistants.

7. Examine and determine competency of radiographic personnel.

8. Establish and maintain adequate storage facilities.

9. Maintain exposure devices, radiography facilities, and associated equipment.

10. Establish and maintain the leak testing program.

11. Establish and maintain the internal inspection system.

12. Perform source replacement and source tagging operations.

13. Conduct quarterly inventories and maintain utilization logs.

14. Establish a survey instrument calibration program.

15. Establish and maintain the licensee's recordkeeping system.

16. Review and insure maintenance of those records not kept by himself.

17. Assume control and institute corrective action in emergency situations.

18. Investigate cause of incidents and determine necessary preventive action.

19. Act in advisory capacity to licensee's management and radiography personnel.

A Note of Caution

The sample set of Operating and Emergency Procedures contained in this appendix is provided for illustrative purposes only. It will be noted these procedures are illustrative of a particular type of in-plant program. Procedures submitted by the applicant for a radiography license must be tailored specifically to fit the facilities, equipment and operations which will be used in the applicant's proposed radiography program. Some parts of the following sample procedures may be applicable and therefore usable by the applicant in preparing his procedures. The sample procedures may omit some instructions which will be necessary as part of the applicant's own operating and emergency procedures.

Inclusion of instructions not appropriate to the radiographic program described by the application as a whole, or the omission of instructions which are needed to provide a complete and adequate set of procedures, may indicate that the applicant has not considered the need for such procedures in sufficient detail, or that he may not fully understand the requirements set forth in Commission regulations. To incorporate instructions not applicable to the proposed radiography program may result in denial of the application.

It will be noted that the sample procedures which follow contain some requirements established by the hypothetical XYZ company which are not requirements of Commission regulations. It will also be noted that certain requirements which are contained in the Commission regulations have been set forth in a manner more restrictive than the related section of Part 20 or Part 31. For example, the following procedures refer in several places to maximum radiation levels in unrestricted areas of 2 mr/hr. The Commission's regulations pertaining to permissible levels of radiation in unrestricted areas, as set forth in § 20.105 (b) of Part 20, are 2 millirem in any one hour or 100 millirem in any seven consecutive days. It should be noted, therefore, that the regulations do not limit radiation dose rates to a maximum of 2 mr/hr, but permit higher dose rates providing that the total quantity of radiation in any unrestricted area during any one hour does not exceed 2 millirem; and during any 7 consecutive days does not exceed 100 millirem. The procedures of the XYZ company were established on the basis of that company's analysis of its own intended use of the licensed material and the requirements set forth in the proce

dures were tailored by that company to meet its own desires regarding the establishment of a radiation safety program.

Operating and Emergency Procedures for XYZ Company

A. Responsibility for over-all radiation protection program

1. The responsibility for the over-all radiation protection program shall rest with the radiography department of the XYZ company under the direction of......

2. The following person has been assigned the duties of radiation protection officer:.

3. Radiographic shift supervisors shall check all radiographic personnel at their job sites at least once per shift during plant operation to ensure compliance with AEC regulations and these procedures.

4. Each radiographer employed in field operations will be inspected at not less than one month intervals to ensure compliance with AEC regulations and these procedures.

B. Production Personnel

1. Radiographers shall be trained and qualified in accordance with Part A of the company's training manual, a copy of which has been filed with the Atomic Energy Commission.

2. Radiographers shall have the authority to use and supervise the use of, while in constant attendance at the site, the sealed sources for which the company is licensed.

3. Other personnel in the radiography department, after training and qualifying as required by the provisions of the company's training manual, will be designated as radiographer's assistants and may operate the exposure equipment under the personal supervision of a qualified radiographer.

4. As personnel become qualified as radiographers and radiographer's assistants, their names and records of qualification shall be kept on file for AEC inspection.

C. Sealed Sources and Devices

1. The company is licensed to use only the sealed sources and devices designated on its license. A copy of the current license is attached to these procedures. 2. Instructions for the safe use of these devices are outlined in Attachment A of these procedures.