ML20035F912
| ML20035F912 | |
| Person / Time | |
|---|---|
| Site: | 07001703 |
| Issue date: | 04/30/1993 |
| From: | NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | |
| Shared Package | |
| ML20035F910 | List: |
| References | |
| PROC-930430, NUDOCS 9304230050 | |
| Download: ML20035F912 (4) | |
Text
-
I GUIDELINES FOR DECONTAMINATION OF FACILITIES AND EQUIPMENT PRIOR TO RELEASE FOR UNRESTRICTED USE OR TERMINATION OF LICENSES FOR BYPRODUCT, SOURCE, ORSPECIALNUCLEARMATERIAI.
U.S. Nuclear Regulatory Commission Division of Fuel Cycle Safety and Safeguards Washington, DC 20555 April 1993 9304230050 930421 PDR ADOCK 07001703 C
2 The instructions in this guide, in conjunction with Table 1, specify the radionuclides and radiation exposure rate limits which should be used in decontamination and survey of surfaces or premises and equipment prior to abandonment or release for unrestricted use. The limits in Table 1 do not apply to premises, equipment, or scrap containing induced radioactivity for which the radiological considerations pertinent to their use may be different.
The release of such facilities or items from regulatory control is considered on a case-by-case basis.
1.
The licensee shall make a reasonable effort to eliminate residual contamination.
2.
Radioactivity on equipment or surfaces shall not be covered by paint, plating, or other covering material unless contamination levels, as determined by a survey and documented, are below the limits specified in Table 1 prior to the application of the covering.
A reasonable effort must be made to minimize the contamination prior to use of any covering.
3.
The radioactivity on the interior surfaces of pipes, drain lines, or ductwork shall be determined by making measurements at all traps, and other appropriate access points, provided that contamination at these locations is likely to be representative of contamination on the interior of the pipes, drain lines, or ductwork.
Surfaces of premises, equipment, or scrap which are likely to be contaminated but are of such size, construction, or location as to make the surface inaccessible for purposes of measurement shall be presumed to be contaminated in excess of the limits.
4 Upon request, the Commission may authorize a licensee to relinquish possession or control of premises, equipment, or scrap having surfaces contaminated with materials in excess of the limits specified.
This may include, but would not be limited to, special circumstances such as razing of buildings, transfer of premises to another organization continuing work with radioactive materials, or cmversion of facilities to a long-term storage or standby status.
Such requests must:
a.
Provide detailed, specific information describing the premises, equipment or scrap, radioactive contaminants, and the nature, extent, and degree of residual surface contamination, b.
Provide a detailed health and safety analysis which reflects that the residual amounts of materials cn surface areas, together with other considerations such as prospective use of I
the premises, equipment, or scrap, are unlikely to result in an l
unreasonable risk to the health and safety of the public.
l l
l
.,,gn.
,n_,-,,,.
3 5.
Prior to release of premises for unrestricted use, the licensee shall make a comprehensive radiation survey which establishes that contamination is within the limits specified in Table 1.
the survey report shall be filed with the Division of Fuel CycleA copy of Safety and Safeguards, V. S. Nuclear Regulatory Commission, Washington, DC 20555, and also the Administrator of the NRC Regional Office having jurisdiction.
The report should be filed at least 30 days prior to the p?anned date of abandonment. The survey report shall:
Identify the premises.
a.
b.
Show that reasonable effort has been made to eliminate residual contamination, Describe the scope of the survey and general procedures followed.
c.
d.
State the findings of the survey in units specified in the instruction.
Following review of the report, the NRC will consider visiting the facilities to confirm the survey.
TABLE 1 ACCEPTABLE SURFACE CONTAMINATION LEVELS b
NUCLIDES" AVERAGE"
MAXIMUM""'
REMOVABLE"*'
2 2
associated decay products 5,000 dpm a/100 cm 15,000 dpm a/100 cm 1,000 dpm a/100 cm Transuranics, Ra-226, Ra-228, 2
2 2
Th-230, Th-228, Pa-231, 100 dpm/100 cm 300 dpm/100 cm 20 dpm/100 cm Ac-227, I-125, 1-129 Th-nat, Th-232, Sr-90, 2
2 2
Ra-223, Ra-224, U-232, 1-126, 1000dpm/100cm 3000 dpm/100 cm 200 dpm/100 cm 1-131, 1-133 Beta-gamma emitters (nuclides with decay modes other than 2
2 2
alpha emission or spontaneous 5000 dpm 8y/100 cm 15,000 dpm By/100 cm 1000 dpm By/100 cm fission) except Sr-90 and others noted above.
- Where surface contamination by both alpha-and beta-gamma-emitting nuclides exists, the limits established for alpha-and beta-gamma-emitting nuclides should apply independently.
bAs used in this table, dpm (disintegrations 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 instrumenta. tion.
[
- Neasurements 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.
d 2
ihe maximum contamination level applies to an area of not more than 100 cm.
2
'The amount of removable radioactive material per 100 cm of surface area should be determined by wiping that area with dry 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.
'The average and maximum radiation levels associated with surface contamination resulting from beta-gamma emitters should not exceed 0.2 mrad /hr at ' cm and 1.0 mrad /hr at I cm, respectively, measured through not more than 7 milligrams per square centimeter of total absorber.
-