records

X. Records

A. Inventory
B. Surveys and Monitoring
C. Source Leak Testing
D. Instrument Calibration

X. RECORDS

The Radiation Safety Division will maintain centralized records as required by the RCC. These records are subject to inspection by the New Mexico Environment Department and the Nuclear Regulatory Commission.
A. Inventory top

Quarterly inventories of radioactive materials utilized at the University under the State of New Mexico Radioactive Materials license are obtained by the Radiation Safety Division by sending each permit holder a printout of current inventories. The permit holder is responsible for determining if the actual inventory for the permit is in agreement with the inventory kept by the Radiation Safety Division.
A physical inventory of all sealed sources that are required to be leak tested and of special nuclear materials is performed at intervals not to exceed six months. Monitoring by instrument is acceptable for verifying the presence of fuel and sources in the Reactor.
B. Surveys and Monitoring top

Authorized users of radioactive materials and other sources of ionizing radiation are responsible for determining external and internal radiation exposures of personnel under their supervision. Records of surveys performed by users to determine external radiation and radioactive contamination levels shall be maintained by responsible persons utilizing sources of ionizing radiation. Radioactive contamination levels greater than the action levels set by the RCC shall be decontaminated or controlled from being spread as soon as the excessive levels are known. Action levels for contamination are listed in part 4 of this section.
Surveys of laboratories by the user must be performed and documented at least monthly. If radioactive materials are not actively used, the radioactive materials storage area must be surveyed at least once per month for contamination. When radioactive materials are used, the work area must be surveyed for contamination. This survey must be performed within the same day as the use when using greater than 10 times the amount listed in Subpart 3, Schedule B of the NM Radiation Protection Regulations. See Table 1.

Table 1

Activity Levels Requiring Surveys Same Day As Use 10 X Schedule B Quantities
Radioisotope	Activity (m Ci)	Radioisotope	Activity (m Ci)
Hydrogen-3 (Tritium)	10,000	Chromium-51	10,000
Carbon-14	1,000	Technetium-99m	1,000
Phosphorus-32	100	Iodine-125	10
Sulphur-35	1,000	Iodine-131	10

Personnel monitors, typically in the form of thermoluminescent dosimeters (TLDs), are used at UNM for detection of x-rays, gamma, beta, and neutron radiation. Individuals whose dose may exceed 10 percent of the applicable limits are required to obtain and use these dosimeters. Dosimeters for detecting external radiation are not necessary in laboratories where only low energy beta emitters such as Hydrogen-3, Carbon-14, and Sulfur-35 are used.
Individuals involved in operations which utilize radionuclides in a uncontained form above the activity levels indicated in the following hazard level table (Table 2), other than metallic foils, plated sources, and human therapy, shall have bioassays performed within one week following a single operation and at periodic intervals for continued operation with radionuclides. The samples may be analyzed at the University of New Mexico.

In the past, periodic studies using bioassay and air sampling techniques have shown that exposure levels for personnel administering therapeutic doses Ł 100 mCi were within acceptable limits for radiation workers. However, in keeping with the ALARA principle, the RCC has established a requirement that all personnel administering radioiodine greater than 1 mCi are required either to submit a urine sample for radioiodine analysis or have a thyroid scan performed by the Nuclear Medicine Department. The bioassay should be performed within 24 to 48 hours after administering the dose. The assay of the urine sample should be performed by the Radiation Safety Division or designee. Documentation of the results for either the urine assay or the thyroid scan must be recorded for future reference.

Depending upon the type of operation and hazard involved, the Radiation Control Committee will consider the need for bioassay at other levels. Contamination spreads, spills, or personal contamination may also warrant bioassay as deemed appropriate by the Radiation Safety Officer.

Table 2

Radionuclide Hazard Groups

Group 1

Very High Hazard

100 m Ci

Group 2

High Hazard

1 mCi

Group 3

Medium Hazard

10 mCi

Group 4

Low Hazard

100 mCi

Pb-210*

Po-210

Ra-226*

Ra-228*

Ac-227

Th-228

Th-230

Np-237

Pu-238

Pu-239

Pu-240

Pu-241

Pu-242

Am-241*

Cm-242

Na-22^*

Ca-34

Sc-46^*

Co-60^*

Sr-90

Ru-106^*

I-125

I-129

I-131^*

Cs-137^*

Ce-144^*

Eu-154^*

Ta-182^*

Bi-210

At-211

Ra-224

U-233

C-14

Na-24^*

Si-31

P-32

S-35

Cl-36

K-42^*

Sc-47

V-48^*

Cr-51^*

Mn-54^*

Mn-56^*

Fe-55

Fe-59^*

Cu-64^*

Zn-65^*

Ga-72^*

As-76^*

Rb-86^*

Sr-89

Y-90

Y-91

Zr-93^*

Nb-95^*

Mo-99^*

Ru-103^*

Rh-105^*

Pd-103

Ag-105

Ag-111

Cd-109^*

Sn-113^*

Te-127^*

Te-129^m*

Ba-140^*

La-140^*

Pr-143

Pm-147

Sm-151

Ho-166^*

Tm-170^*

Lu-177^*

Re-183^*

Ir-190^*

Ir-192

Pt-191^*

Pt-193^*

Au-196^*

Au-198^*

Au-199^*

Tl-200^*

Tl-201^*

Tl-202

Tl-204

Pb-203^*

Rn-220

Rn-222^*

U-235

H-3

Be-7^*

F-18

Ni-59

Zn-69

Ge-71

Tc-99^m

U-238

Natural Thorium

Natural Uranium

Noble Gases

*Emits gamma radiation in significant amounts

The Radiation Safety Division shall perform surveys at least quarterly for contamination in all laboratories where unsealed radionuclides are used. Laboratories which possess activities greater than or equal to the smallest Annual Limit on Intake (ALI), as specified in the NMED Radiation Protection Regulations, will be surveyed at least monthly. Standard modifying factors may be applied to the activities possessed based upon actual materials use in the laboratories. The RCC sets action levels for alpha, beta, and gamma contamination well below the limits reportable to the NMED to facilitate early detection of potential problems.
Contamination found in unrestricted areas should be immediately decontaminated to background levels. When it is not possible to get to background levels, the user must ensure that the amounts do not exceed the contamination levels listed in Table 3.

Except for human diagnostic and therapeutic applications, action levels for removable contamination per 100 cm² for hazard groups listed in Table 3 are as follows:

Table 3 - Acceptable Surface Contamination Levels

Nuclide ¹	Average ^2,3	Maximum ^2,4	Removable ^2,5
U-nat, U-235, U-238, and associated decay products	5,000 dpm a /100 cm²	15,000 dpm a /100 cm²	1,000 dpm a /100 cm²
Transuranics, Ra-226, Ra-228, Th-230, Th-228, Pa-231, Ac-227, I-125, I-129	100 dpm/100 cm²	300 dpm/100 cm²	20 dpm/100 cm²
Th-nat, Th-232, Sr-90, Ra-223, Ra-224, U-232, I-126, I-131, I-133	1,000 dpm/100 cm²	3,000 dpm/100 cm²	200 dpm/100 cm²
Beta-gamma emitters (nuclides with decay modes other than alpha emission or Spontaneous fission) except Sr-90 and others noted above.	5,000 dpm/100 cm²	15,000 dpm /100 cm²	1,000 dpm/100 cm²

¹Where surface contamination by both alpha- and beta-gamma-emitting nuclides exists, the limits established for alpha- and beta-gamma-emitting nuclides should apply independently.

²As used in this table, dpm (disintegration per minute) means the rate of emission by radioactive material as determined by correcting the counts per minute observed by an appropriate detector for background, efficiency, and geometric factors associated with the instrumentation.

³Measurements of average contaminant should not be averaged over more than 1 square meter. For objects of less surface area, the average should be derived for each such object.

⁴ The maximum contamination level applies to an area of not more than 100 cm².

⁵ The amount of removable radioactive material per 100 cm²of surface area should be determined by wiping that area with filter or soft absorbent paper, applying moderate pressure, and assessing the amount of radioactive material on the wipe with an appropriate instrument of known efficiency. When removable contamination on objects of less surface area is determined, the pertinent levels should be reduced proportionally and the entire surface should be wiped.

Surface contamination surveys should be conducted for both removable and fixed contamination before facilities or equipment are released from restricted to unrestricted use, to ensure that they meet these limits. A standardized method for smear testing of a relatively uniform area should be used to aid in comparing contamination at different times and places. A smear taken from an area of about 100 cm2 is acceptable to indicate levels of removable contamination. Areas utilized by patients undergoing medical diagnosis or therapy with unsealed radionuclides will be released from control at levels as low as reasonably achievable. The maximum release limits for such areas is 2 mrem/hr at 1 meter (external radiation dose rate).

Concentrations in Air and Water released to the Environs

Refer to NMED Regulations, Subpart 4, Section 461, Appendix B, Table II. Release of radioactive materials to the University sewage system is prohibited.

C. Source Leak Testing top
All sealed sources, which are required to be leak tested, shall be tested within required intervals by the Radiation Safety Division in accordance with NMED license requirements. D. Instrument Calibration top
The Radiation Safety Division will maintain records of calibration data on portable radiation survey instruments used for external radiation measurements. Such instruments are calibrated at least annually. Low range survey instruments are calibrated by the Radiation Safety Division. High range instruments are calibrated by an outside vendor.