ML20209F522
| ML20209F522 | |
| Person / Time | |
|---|---|
| Issue date: | 09/02/1986 |
| From: | Block S NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Federline M NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO) |
| Shared Package | |
| ML20209F528 | List: |
| References | |
| IEC-81-07, IEC-81-7, IEIN-85-092, IEIN-85-92, NUDOCS 8609120180 | |
| Download: ML20209F522 (8) | |
Text
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SEP 219R6 MEMORANDUM TO: Margaret Federline, Technical Assistant, EDO FROM: S. Block,llealth Physicist
SUBJECT:
" REVIEW OF DRAFT ANSI 13.12 " SURFACE RADIOACTIVITY GUIDES FOR MATERIALS, EQUIPMENT AND FACILITIES TO BE RELEASED FOR UNCONTROLLED USE."
The Emergency Preparedness and Radiological Protection Branch of the Division of Radiation Safety and Standards (RV) has reviewed the subject ANSI standard.
We find some items in its contents that cause us to have some reservations for its acceptance for release without qualification.
Our concerns include the following relevant issues:
(1) IE Information Notice No. 85-92 " Surveys of Wastes Before Disposal from Nuclear Reactor Facilities" (December 2, 1985) references an earlier IE Circular 81-07 " Control of Radioactively Contaminated Material" (May 14, 1981) that also provided guidance on surveys and control of radioactively contaminated equipment. In reviewing these IE documents, we note that neither of them addresses established release limits for uncontrolled use of contaminated equipment. Consequently, although the draft ANSI 13.12 provides guidance to licensees for establishing criteria for evaluating radioactive contamination, Table 1, " Surface Radioactivity Guide", should not be used by licensees as limits for release for uncontrolled use of materials, equipment or facilities since NRC has no established guidance on release limits thereof. The table however may be used, on a case by case basis, under conditions of license termination as described in Regulatory Guide 1.86 " Termination of Operating Licenses for Nuclear Reactors." A footnote should be added to the table or the text that clearly expresses this limitation on use of the ANSI standard.
(2) The technical basis for the rationale for using the Surface Radioactivity levels of Table 1, to provide a dose commitment as described in Appendix B, is not really convincing. The computations are confusing and not complete and thus are not helpful to the potential user of the Standard. Attachment 1 provides a simpler alternative method for computing the dose equivalent that uses dose conversion factors and methodology that should be more familiar to, at least, licensees.
! Ilowever, the attached computations provides no better justification for use of the values of Table 1 excepting to demonstrate that they provide small fractions of permissible levels of radiation exposure.
(3) The so called " References for Appendix A" (pg A-6 thru A-8) is really a Bibliography of the subject discussed. It would be more useful if a specific reference number was flagged to the reader (as given in Appendix B) in a section of interest rather than have it buried in the Bibliography. The reader could then refer to this reference for needed l
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detailed information. Therefore the references in Appendix A should have the same reference format as Appendix B.
.(4) Attachment 2 addresses other items that should be brought to the attention of the Standards Committee.
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Attachment 1 Ingestion Assume consumption of activity on 10 cm 2 contaminated surface each day (see top of page B-3). Activity is taken as Cs (the activity of interest for NRC licensed facilities being decommissioned) with a G = 5000 d/m 100 cm3 (see Table 1 Group 3). Then, using more familiar units of activity, we get:
~0 5000 d/m x 10 cm 2 = 5x102 dim = 2.27 x 10 uCi ingested 100cm3 day 2. 2x10d/m day uCi 137 From Reg. Guide l'.109 24 the bone dose factor for a child consuming this Cs activity is 3.27 x 10 mrem /pci ingested, so that:
~4 ~4 2.27 x 10 uCi x 365 days x 106pci x 3.27 x 10 mrem = 27 mrem day yr uCi pCi yr This is a more useful number than the dose commitment and Bq values given in ANSI 13.12 page B-3.
If this activity is resuspended in water and all of it was consumed, the dose to the child (ingestion pathway) should be the same (i.e. 27 mrem /yr).
Inhalation Again using a valve of G = 5000 d/m, and the value for C (in the ANSI 100 cm3 standard page B-6), where C = G x 1.47 x 10 ~0 Bq/H3 , we get:
C = 5000 x 1 7 x 10 3
= 7.35 x lo d g/m 3 7.35 x 10 B 1z = 3.3 x 10 uCi 4x t! 2. 2x 10Bq F uCi From Reg. Guide 1.109, using a teenager as the critical person, the breathing rate is 8000 M 3/yr, so that:
~9 -6 uCi x 106 pCi = 26.4 pCi inhaled 3.3 x 10 uCi x 8 x 103M3 = 26.4 x 10 F y7 yr uCi yr Lung dose factor for 90 Sr, from Reg. Guide 1.109, = 2 x 10 -3 mrem /pCi inhaled
-3 -3 26.4 pCi x 2x10 mrem = 52.8 x 10 mrem yr pCi yr
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_2 Skin Dose Assuming 10% of the contamination is transferred to the skin (N13.12 model) we get:
500 d/m = 5 d/m 100 cm 3 ca z 0
= 2.27 x 10 -6 uCi 2.2x10 d/m cm 2 uCi Healy (Ref. 4 of N13.12) provides a curve (Figure 1) which indicates:
9 RADS /hr uCi/cm 3 90 3,j 90 7, at 7 mgs/cm 2 of skin for the 2.2 NEV p of j
so that:
-3 mrads 2.27 x 10 ~0 uCi x 9 RADS /hr x 103 mrads = 20.43 x 10 em d uCi/cm 3 RAD hr and 20.43 x 10 -3 mrads x 8760 hrs = 179 mrem hr yr yr (compared to 140 mrem in N13.12).
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Attachment 2 (1) Since Table 1 is in units of d/m, and radiation detectors provide response to radiation in c/m, provide a standard procedure for converting -
count rate into disintegration rate. The efficiency of detectors normally given by manufacturer's instruments, probably includes geometry as the foremost factor. However, backscattering, window and air thickness, side scatter, self-absorption of surface contamination should also be considered in the efficiency conversion factor for c/m to d/s.
- (2) Pg A-3 Section A-2.2. The term " unrestricted release levels" is used in this section. Is this the same as " uncontrolled release levels" also used throughout the standard. Shouldn't the standard be consistent in this regard?
(3) PageB-327nextt last paragraph 2E6Pl ease explain the origin of 10,000 i Bq for AC and 200,000 Bq for Ra. Also show the calculation for
'! the dose commitment of 92 mrem and 4.6 mrem respectively. Mixture of SI units (Bq) and non-SI units (mrem) is also inconsistent.
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LETTER BALLOT HEALTH PHYSICS SOCIETY STANDARDS COMMITTEE TOPIC: Proposed Standard N13.12 SURFACE RADIOACTIVITY GUIDES FOR MATERIALS, EQUIPMENT, AND FACILITIES TO BE RELEASED FOR UNCONTROLLED USE .
Authorized By: Lowell Nichols, HPSSC Chairman Distributed By: Nancy Johnson, Standards Coordinator, on July 28, 1986 Return To: Nancy Johnson, Standards Coordinator Health Physics Society 1340 Old Chain Bridge Road, Suite 300 McLean, VA 22101 DUE DATE: SEPTEMBER 8, 1986 Do you vote that the HPSSC approve the Proposed Standard N13.12?
[ ] Yes, without qualifications
[ ] Yes, with the qualifications stated below
[ ] No, for the reasons stated below
[ ] Abstain, for the reasons stated below
,.i
.. Name Date
, COMMENTS:
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I HEALTH PHYSICS SOCIETY RICHARD J. BURK, JR., Executive Secretary 1340 Old Chain Bndge Road. Su'te 300 McLean, VA 22101 Telephone (703) 790-1745 MEM0RANDUM DATE: July 28, 1986 T0: HPSSC Members FROM: Nancy Johnson, Standards Coordinator SU3J: N13 12 Ballot Enclosed for your review is a revised draft of N13.12, " Surface Radioactivity Materials, Equipment, and Facilities To Be Released for Guides for Uncontrolled Use." At the HPSSC Annual Meeting in Pittsburgh on June 29th, the Working Group Chairman announced that there were a few changes to the draft that was distributed for ballot action on June 6th. It was decided at that time that any June 6th ballots were considered rescinded and that a new
,,. ballot would be distributed with the modified standard.
Please note that the Ballot Closing Date is September 8th. Be sure to have your ballot returned to me by that deadline.
Th'ank you and best wishes.
/nkj doc 0459N Enclosures cc: Section Chairs (w/ encl.)
J. Poston (w/ encl.)
P. "iemer (w/ encl.)
E. Eisenhower (w/ encl.)
.