ML20012D535
| ML20012D535 | |
| Person / Time | |
|---|---|
| Issue date: | 03/12/1990 |
| From: | Bernero R NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Morris B NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| References | |
| REF-WM-3 NUDOCS 9003280020 | |
| Download: ML20012D535 (6) | |
Text
.-
MARi11@
, MEMORANDUM FOR:
Bill M. Morrisc Director Divisien of Ryulatory Applications Office of Nuclear Regulatory Research
-FROM:
Robert M. Bernero, Director Office of Nuclear Material Safety and Safeguards
SUBJECT:
COMMISSION PAPER ON INTERIM RELEASE CRITERIA i
FOR DECOMMISSIONING STRUCTURES AND S0ILS As requested by your memorandum of February 15, 1990, we have reviewed 7
the above Comission Paper on " Interim Release Criteria for Decommissioning Structures and Soils. Enclosed are consnents on the Commission Paper and its
.t Enclosures 1 and 3; and the Draft Federal Register Notice, it is importan:.
that this guidance be issued soon, and I am looking forward to concurring on it when these conenents have been taken into consideration.
(Signed) Robed M. Bens Robert M. Bernero, Director L
Office of Nuclear Material Safety and Safeguards
Enclosures:
As stated Distribution:nContral:11]e;C D
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J., ; n ENCLOSURE Lx COMMENTS ON COMMISSION PAPER
" INTERIM RELEASE CRITERIA FOR DECOMMISSIONING STRUCTURES AND S0ILS" L
Commission Paper Comments:
1.
Page 31 first paragraph The sentence "the other options of the Branch Technical Positien are not affected by-these new criteria" -- should be deleted. Certain c9tions of the Branch Technical Position are guidance for disposal under 10 CFR 20.302(a) by burial and are not relevant to site deconnissioning.
2.
Page 3; first paragraph Delete the-last sentence referring to "the risk basis for these guidance documents". The sentence should read "This comparability reflects the l
cautious approach taken to cecou.assiunib9 guitarce in the past."
3.
Page 3 second paragraph We suggest that the last sentence of the second paragraph of the introduction on page 2 of enclosure 1 should be added to the end of the first. full paragraph on page 3 of the Commission Paper.
4.
Page.4: line 24 SuR/mr should be SuR/hr.
5.
Page 4; first_ full-paragraph We suggest that the first full paragraph on page four be deleted or be modified to discuss the implications of the large number of
... intake parareter values..." and the uncertainty of the resulting tabulated nunters, the role of worst case vs. reality in the modeling end calculations of internal doses and how the models and input parameters
"... simply represent a basis for... unrestricted release."
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6.
Page 51 second paragraph, last sentence We suggest modification of this sentence to read:
"The staff bel.s as that the EPA standards, developed only for clean up of old urania mill sites, should be studied further as guidance criteria for clean up of other types of facilities involving the contar..ination of radium." It should be pointed out clearly that the EPA' standards, if adopted, could result in a dose exceedirig 500 mrem. We strongly feel that' this information should be presented to the Commission.
This demonstrates that achieving 10 mrem effective dose equivalent for radon (and probably a few other naturally-occurring radionuclides) is not a practical goal. Because the radium and radon component of the total effective dose equivalent is critical and probably dominant at some scarce-material contaminated sites, it is considered that it would not be credible to issue guidance which lacks values for these radionuclides.
Instead, the Federal Register notice should emphasize this topic in its call for coments, as an area especially subject to reconsideration.
h Furthermore, the guidance should specif table values for Ra-226 and Ra-228 (+D)y more exactly to what extent the I
include the release of radon. Do I
these values in Table 1 include any consideration of the release Rn to the building atmosphere, and if so, in what way?
If they do not, that
.should be stated explicitly.
1.
_ Enclosure 1 Comments:
P 1
1.
Sumary Replace the last sentence.of the second paragraph (as in coment 0 under Comission Paper) with "The-comparability reflects the cautious approach taken ~ to decomissioning guidance in the past."
2.
Delete the last sentence of the first paragraph.
If the levels (concentrations) are safe at ground surface, why should they be more hazardous when buried? Perhaps some other concept was intended here that
[
has not been expressed clearly.
t 3.
P, age 3;firstparagrag It is not apparent why "This criterion can not be applied to subsurface contaminant 3... " The sentence should be supplemented by a statement that the covered soil will provide a shield to reduce the gamma radiation and the true reading can not be obtained.
4 P, age 3; second paragraph See comment 5 on Comission Paper.
6s 4
f: 5.
Page 3; last paragraph See Comment No. 6 on the Commission Paper 6.
Page 4; first paragraph This paragicple pc. icu, :.u.e explanation of the peculiar usage that appears in Tables 1 and 2 when daughter radionuclides are includeJ.
It is, however, essential to include a footnote to each table to mcke the usage clear. An example H il help also, (e.g., for "Ba-140 + D," the 9.5 Bq/g of Ba-140 in Table 1 consists of 4.75 Bq/g of La-140 and 4.75 Bq/g of i
Ba-140).
7.
Page 16; first paragraph Some remark.thould be made that if a pathway was not included here, (e.g.,
plant uptake from contamination in irrigation water), it does not mean it should be excluded from site specific constocratichs.
If a pathway appears applicable, it should be considered.
8.
Page 16; first paragraph The sentence "To avoid counting the residual activity twica,..." in the first paragraph appears to contraoltt the 1irst sentence in the second paragraph and the first sentence of the last paragraph on page 17. This dpparent inconsistency should be reconciled.
9.
Qge16;second.parag_raph It appears that the only radionuclide for which contaminatior, in a soil layer thicker than 15 cm is considered as radium.
It is, however, not uncommon to find that the contamination extends to a greater depth.
If table 2 is intended to be practicable and applicable to soil contamination thicker than 15 cm, the remark on line 4 should be raodified somewhat to dCcomreodate other situations.
We suggest the change of 15 cm to " thin layers."
10.
Page 17; section on total inventories and drinking water The heading should be changed to " Total Inventories and the Drinking Water Scenario."
The first paragraph of this section should be modified to describe briefly l
the relationship of the total inventory of residual contamination to the radionuclide concentrations in drinking water.
l.
11.- The Interim Guidance should incorporate a policy of ALARA 1
l j
1 1 l Tables 1 and 2 1.
These tables contain a number of values which raise questions about their j
accuracy and validity. Commonly, these involve radionuclides which can be j
omitted with no detriment to the usefulness of the guidance. The complete set of tables must have careful scrutiny to weed out inaccuracies, nonsensical values and instances where tremendous disparities exist between values for the same radionuclide in the tables.
It is strongly recommended that this review of the tables be performed by persons collectively having experience and expertise with the full range of practices involving licensable radioactivity, past practices as well as contemporary. A few examples of the problems with the table follows:
a)
In table 2, the Surface Soil value for K-40 is 7.7 pC1/g, This is a
)
ubiquitous naturally occurring radionucide. Soil naturally averages 10 pC1/g K-40 and may range up to 50 pC1/g.
It is recommended that K-40 be omitted from the Guidance.
b)
In Table 1, under Building Vohm Sources, the value for U-238 is 1600 pC1/g.
This is appreciably greater than the (non-health-related)
]
lower limit for source material uf 0.05 weight percent (about 170 pCi/g of U-238 by itself).
This is unecce dable, and some correction is needed, c)
InTable1,underBuildingSurfaceSources,thevglueforCo-60is 2
12,000 dpm/100 cm,'
In the past, 1000 dpm/100 cm has been used as an operational value. This is tog great a discrepancy to be ignored. Also forH-3,8gmilliondpm/100cm is allowed; in the past an average of 5000 dpm/100 cm has been allowed.
l 2.
Although it may be aesthetically pleasing to include 200 radionuclides, l_
for many of those listed there is little likelihood that they will be of interest in decontamination for release for unrestricted use.
A sampling t
of the tables indicates that one fourth of the radionuclides could be omitted simply because their (and their decay products') half-lives are so short. Deleting them would remove some of aesthetically displeasing aspects of the tables.
l 3.
The terms and units would be defined at length. What is encompassed by
" Total Inventory?" Are those doses annual doses or 50-year committed l.
doses? What is the meaning of thwse specified level:i; e.g., are the L
averages over an area, (e.g., per NOREG-2082), or are they absolute l
maxima? The Interim Guidance is incomplete without this basic information.
1 L
L 1
L Tables 1 and 2 1
4.
The footnotes in Tables 1 and 2 should cite the document in which Appendix i
D is to be found.
The conversion of pC1 to Bq needs to be revised.
1
8
-,. Draft Federal Register Notice Comments I
1.
The Federal Register tiotice (FRN) should include a table comparing the Interim Guidance values to those in Reg. Guide 1.86, the BTp (46 FR 52061) and other guidance used for decontamination of structures and soils. The comptrison should include the usage of the levels, e.g., whether they_
are averages over an area or absolute n4xima.
1 2.
The FRN should include a discussion of the risk of 10 mrem TEDE per year in terms of the health risk indicated by the evaluations in DEIR V and UNSCEAR 88.
If the Interim Guidance includes values based on something other than 10 mrem / year TEDE, those values should also be discussed in terms of their health risks implied by the findings of BEIR IV, BEIR V and UNSCEAR 88, etc.
If feasible, past guidance (e.g., Reg. Guide 1.86),
l should be discussed in the same context.
3.
The FRN'should include a discussion of the role of ALARA in application of j
the Interim Guidance.
The discussion should specifically _ address racionuclide where values lower than those of the Interim Guidance have J
been used in the past without apparent undue hardship.
4.
The draft FRN lacks some of the standard boiler plates. An especially grievous omission is the omission of a call for comments.
Considering the difficulties met in bringing the Interim Guidance to this stage, constructive criticism from the prospective users should be welcome and worth putting up with.
The comments should call nut areas for s >ecial attention including (1) the guidance for radium and radon (2) tie guidance for other naturally occurring radionuclides, (3),the drinking water scenario, and (4) potential modifications to make the guidance more compatible with radiological survey techniques.
l l
t
.