ML20214W815
| ML20214W815 | |
| Person / Time | |
|---|---|
| Issue date: | 05/28/1987 |
| From: | Lohaus P NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | James Anderson ENERGY, DEPT. OF |
| References | |
| REF-WM-60 NUDOCS 8706160195 | |
| Download: ML20214W815 (19) | |
Text
. . - . -.. . - - . . . - . _ _ - . - - . . - .. .
NAY 28198f
, q ~ +9_h~
W!.1 ft:cmd Fi>
n a a, . . . .
- I -
Mr. James R. Anderson, Project Manager U " ' ' '--
i Uranium Mill Tailings Project Office - D W"'- t " - -
-- --~ _ _. _ _ _
U.S. Department of Energy - - - - - -_
Albuquerque Operations Office b
- j. P.O. Box 5400 e M d.._ ,A/i
/-
Albuquerque, NM 87115
Dear Mr. Anderson:
Enclosed are our comments on the Preliminary Final Remedial Action P.lan for the Riverton Site. We have also included for your consideration several comments on the Preliminary Final Environmental Assessment for this site. . We understand that you and members of your staff are planning to meet with NRC's Uranium Recovery Field Office and representatives of this office on June 3,1987 in Denver. At that time we will be pleased to discuss these comments as well as other issues related to the Riverton project. 7 Should you have questions on the enclosed comments prior to that time, please contact George Pangburn of my staff at FTS 427-4160.
Sincerely, Estani SigiedDr Paul H. Lohaus, Acting Chief
- Operations Branch Division of Low-Level Waste Management and Decommissioning
Enclosures:
As stated DISTRIBUTION: ,
LLWM SF V KWestbrook l NMSS r/f TJohnson 4
GPangburn JStarmer MFliegel MTokar PLohaus JGreeves CRogers MWeber PNe GGnugnoli LLoh Alf ,y _
n ,,
,4 : :
OFC: LLOB g :LL0 g- ------.
- LLOE j : :
3
.i
- NAME
- GPangburn :MFliegel :PLo us : : : :
i
3,.f}-'8:
DATE: 5/ 7 /87 :5/nGI/87: 5/2387: : :
s OFFICIAL ~ RECORD COPY B706160195 870528 PDR WASTE WM-60 PDR
I -
x '
I I
l I
UMTRA DOCUMENT REVIEW FORM SECTION 1 Site: Riverton , Date: April 1987 Document: Preliminary Final RAP Consnentor: NRC Comment: 1 Page: 15- -
The RAP's description of subsurface features at the Riverton site incorrectly states that the sandy gravel beneath the site acts as a " perched water-table aquifer." This statement is based on a 1983 unpublished Environmental Assessment by Ford, Bacon, and Davis. More recent evaluations of the Riverton site (e.g., the final Environmental-Assessment (DOE, 1987)) have failed to demonstrate the existence of shallow perched groundwater beneath the site.
The interconnection of the shallow groundwater to deeper aquifers is important to decisions about the need to restore or control the shallow contaminated aquifer. Therefore, the RAP should clearly- state that the shallow alluvial aquifer is hydraulically connected to deeper hydrogeologic units (i.e., it is not perched) or demonstrate that the ' shallow groundwater is perched because. it is separated from deeper aquifers by an unsaturated zone.
SECTION 2 Response: Page By: Date:
Plans for Implementation:
l i
SECTION 3 Confinnation of Implementation:
Checked by: , Date:
Approved by: , Date:
5 0
UMTRA DOCUMENT REVIEW FORM SECTION 1 Site: Riverton , Date: April 1987 Document: Preliminary Final RAP Comentor: NRC Comment: 2 Page: 18 -
The RAP states that contaminated groundwater would require at least 20 years to migrate from the unconfined aquifer to the first confined sandstone and an additional 1800 years to migrate from this unit to the deeper sandstones below 200 feet depth. The RAP does not, however, summarize the calculations that support these estimates or cite a reference that provides the calculations.
The RAP should be revised to sumarize the technical basis that supports these estimates or cite a document that describes the calculations in sufficient
. detail. The basis for the calculations should justify the parameter values selected for the calculations, as well as describe the assumptions and the conceptual model upon which the calculations are based.
SECTION 2 Response: Page By: Date:
Plans for Implementation:
SECTION 3
- Confirmation of Implementation:
Checked by: , Date:
j Approved by: . Date:
J
, i-UMTRA DOCUMENT REVIEW FORM SECTION 1 Site: Riverton .
Date: April 1987 Document: Preliminary Final RAP Commentor: NRC Comment: 3 Page: 20 .
The RAP states that contaminated groundwater at the Riverton site does not pose appreciable health hazards based on comparisons of the contaminant concentrations with the EPA primary drinking water standards as described in the Environmental Assessment. These statements may be misleading because two of the most important contaminants at the Riverton site, uranium and molybdenum, are not included in EPA's primary drinking water standards.
The RAP should be revised to delete the conclusion that groundwater contamination at Riverton does not pose any appreciable hazards or to demonstrate the absence of such hazards.
SECTION 2 Response: Page _ By: Date:
Plans for Implementation:
l l
l SECTION 3 Confirmation of Implementation:
Checked by: , Date:
Approved by: , Date:
, ?,
e i
l' l
i UMTRA DOCUMENT REVIEW FORM SECTION 1 l-Site: Riverton .
Date: April 1987
- Document
- Preliminary Final RAP Comnentor: NRC j Comment: 4 Page: 21 .
} The RAP states that after the Riverton processing site has been i decontaminated, the site will be regraded, revegetated, and released for
! unrestricted use consistent with existing local land use controls. Release of 1 the site for unrestricted use, however, may be inconsistent with institutional l
controls imposed at the site to preclude use of contaminated groundwater. The i
RAP should be revised to indicate that potential release of the Riverton i d
processing site for unrestricted use will be contingent upon the imposition, or lack thereof, of institutional controls for groundwater protection.
f SECTION 2 l Response: Page By: Date:
4 i
Plans for Implementation: ,,
l 4
J I
I SECTION 3 I Confirmation of Implementation:
) Checked by: , Date:
1
! Approved by: , Date:
i i
- .. . - . - - - . _ - - - . . ~ _ , _ _ . _ _ _ . , _ , . . . . . _ _ _ . . . , _ _ . _ , , __ _ _ , , . _ _ _ , _ ., , _ . . _ _ _ _ ,,
=
e, 6 UMTRA DOCUMENT REVIEW FORM SECTION 1 ,
Site: Riverton .
Date: April 1987 Document: Preliminary Final RAP Comentor: NRC l Comment: 5 Pages: 24 and 26 .
The RAP states that DOE will remove contaminated subgrade materials at the Riverton processing site. The RAP also states that relocation of the tailings to the Gas Hills site will eliminate the source of future groundwater contamination. Based on the definition of " contaminated," however, I
decontamination will not include removal of sediments beneath the site that have been contaminated with non-radiological constituents unless they occur with radiological constituents above the concentration limits provided in 40 CFR Part 192 (5 pCi/g and 15 pCi/g of Ra-226). Sediments contaminated with non-radiological . constituents may remain on-site after completion of the decontamination process and may constitute a long-term source of contaminants to shallow groundwater beneath the site. Although EPA standards for groundwater protection are not in place at this time, DOE should recognize that by not removing such material during. site excavation, they may in the long run be coimitting to more extensive efforts to comply with the standards once promulgated and restore the aquifer.
SECTION 2 Response: Page By: Date:
l Plans for Implementation:
SECTION 3 Confirmation of Implementation:
Checked by: , Date:
Approved by: , Date:
5:
UMTRA DOCUMENT REVIEW FORM SECTION 1 Site: Riverton , Date: April 1987 Document: Preliminary Final RAP Commentor: NRC Comment: 6 Page: 26 The RAP states that natural restoration will reduce concentrations of contaminants in shallow contaminated groundwater to background levels within approximately 45 years and cites the Environmental Assessrent as the basis for this estimate. The assessments in the EA, however, do not consider desorption and release of less mobile contaminants than the sulfate used in the solute transport model. The decreased mobility of contaminants such as molybdenum compared with sulfate may be evident in comparisons of the extent and rate of migration of their respective contaminant plumes in shallow groundwater
, downgradient of the site. Therefore, the RAP should be revised to indicate that plumes of contaminated groundwater may persist long after the estimated 4
45-year period for natural restoration as indicated in the RAP and the EA.
SECTION 2 i
- Response
- Page By: Date:
Plans for Implementation:
L f
SECTION 3 Confirmation of Implementation:
Checked by: , Date:
Approved by: , Date:
1
- - - , - ~ , - --.c . - r ,, - -., .,_, - ,~.-m , . - . - , , . . , . - , - - - , - e.---.
.- t f UMTRA DOCUMENT REVIEW FORM SECTION 1 Site: Riverton , Date: April 1987 Document: Preliminary Final RAP .
Commentor: NRC Comment: 7 Page: 26 -
The RAP states that DOE will construct a small evaporation pond with a liner
! to ensure groundwater protection. The RAP does not, however, provide the design characteristics of the pond to ensure groundwater protection. For 1 example, the RAP does not indicate whether the pond will be lined with
- low-permeability clay or flexible synthetic material. The RAP should be revised to provide design characteristics of the evaporation pond to protect
~
groundwater against additional contamination, i
SECTION 2 Response: Page By: Date:
Plans for Implementation:
SECTION 3 Confirmation of Implementation:
Checked by: , Date:
Approved by: , Date:
., . o UMTRA DOCUMENT REVIEW FORM SECTION 1 Site: Riverton , Date: April 1987 Document: Preliminary Final RAP Commentor: NRC Comment: 8 Page: 26 i The RAP does not indicate whether DOE will impose any institutional controls as interim measures to protect humans from contaminated groundwater prior to selection of final measures to comply with the EPA standards. The RAP should be revised to demonstrate that such institutional controls are not necessary to protect the public or to describe the type of controls that will be implemented in the interim prior to DOE's selection of remedial measures for groundwater protection.
SECTION 2 Response: Page By: Date:
Plans for Implementation:
SECTION 3 Confirmation of Implementation:
Checked by: , Date:
Approved by: , Date:
_ . ~_ . __ . . _ - - -- __ _ _ _ _-_ _..
l i
4 UMTRA DOCUMENT REVIEW FORM SECTION 1 Site: Riverton . Date: April 1987 Document: Preliminary Final RAP Commentor: NRC Comment: 9 Page: 26 -
j The Environmental Assessment (pages C-105,109,- 157,159,169,171, and 175) 1 for remedial actions at the Riverton site indicates that confined groundwater may have been contaminated by seepage of shallow contaminated groundwater beneath the site. The RAP, however, does not discuss or identify this
, contamination. Since the confined groundwater system at Riverton is used more heavily than the shallow system, existing and potential future contamination of the deeper confined system may be more significant than existing contamination in the shallow system. Therefore, the RAP should be revised to consider the contamination of the confined groundwater system or demonstrate that as a result of the remedial action, such contamination is not expected to -
j occur.
i SECTION 2 Response: Page By: Date: ,
4 Plans for Implementation:
i i
SECTION 3 i
Confirmation of Implementation:
I l
- Checked by: , Date: i Approved by: ,Date: i 1
i
_ _ - - - - __ ,m. _ , . , . _ _ _ . . _ . , , _ _ _ _ _ _ . , - _ _ __ _ _ _ _ _ _ _ , - _ . , , , . _y . . , , . , , . , , , , , - _ , --
e--,
UMTRA DOCUMENT REVIEW FORM SECTION 1 Site: Riverton , Date: April 1987 Document: Preliminary Final RAP Commentor: NRC Comment: 10 Page: 28 -
The RAP states that dewatering of ths tailings may be required prior to excavation and relocation to the Gas H111s site. The following issues have been identified for the dcwatering of the tailings prior to relocation:
1.) The RAP does not discuss or justify the selection of specifications for the dewatering system. For example, the RAP does not estimate pumping rates or locations.
2.) As indicated in Comment 7, design characteristics for the evaporation pond are needed. The RAP should indicate that the evaporation pond has been designed with adequate capacity to collect ani evaporate contaminated water that may be extracted using the dewatering
. system. ,
In addition to the operational benefits of dewatering the tailings, this activity may represent an opportunity to begin restoration of the shallow contaminated aquifer beneath the site. DOE may wish to consider revising the RAP to reflect this consideration.
SECTION 2 Response: Page By: Date:
Plans for Implementation:
SECTION 3 Confirmation of Implementation:
Checked by: , Date:
1 Approved by: , Date:
b UMTRA DOCUMENT REVIEW FORM SECTION 1 Site: Riverton .
Date: April 1987 Document: Preliminary Final RAP Commentor: NRC Comment: 11 Page: 29 .
Section 4.4.8 should be revised to include a commitment from DOE to restore borrow areas prior to completion of remedial actions at the Riverton site.
SECTION 2 Response: Page By: Date:
Plans for Implementation:
SECTION 3 Confirmation of Implementation:
Checked by: . Date:
Approved by: , Date:
UMTRA DOCUMENT REVIEW FORM SECTION 1 Site: Riverton . Date: April 1987 Document: Preliminary Final RAP Commentor: NRC Comment: 12 Page: 41 -
The text should be revised to indicate that long-term monitoring, maintenance, and/or control may be necessary at the decommissioned Riverton processing site depending upon measures selected for groundwater protection.
SECTION 2 Response: Page By: Date:
Plans for Implementation:
1 i
SECTION 3 Confirmation of Implementation:
Checked by: , Date:
Approved by: , Date: l l
, , i
. 1
- i. l
\
t UMTRA DOCUMENT REVIEW FORM i
SECTION 1 Site: Riverton, WY Date: May 6, 1987 ,
i Document: Preliminary Final RAP t
! Commentor: NRC
! Coment: 13 Page: B.5
! A review of the sampling data presented in Appendix C of the draft PSCR :
- (June, 1984) indicates that the radiological characterization did not determine i
the full extent or level of contamination. Samples obtained at the bottom of
[
several boreholes show high Ra-226 concentrations which indicate that the depth
! of contamination is greater than the depth of characterization. The uncertainty associated with the extent of contamination can result in
< underexcavation of the contaminated material. If additional radiological e characterization is not performed prior to construction, then DOE should i,
understand that continual testing of the material for Ra-226 levels during clean-up l operations would be necessary to assure that all contaminated material has been t r
1 excavated.
(
) SECTION 2 .
Response: Page By: Date: ,
j
- r i Plans for Implementation
- l SECTION 3 j Confirmation of Implementation:
I Checked by: . Date: :
, Date: I
! Approved by:
l I
I i :
1 I
i i
r
6 UMTRA DOCUMENT REVIEW FORM .
4 SECTION 1 Site: Riverton, WY Date: May 6, 1987 Document: Preliminary Final EA Commentor: NRC Comment: 1 Page: General During our review of the draft EA (October,1984), the staff expressed a concern about the adverse effects of partial inundation of the pile during a flood event on the stability of the designed slopes. Discussions on the SIP alternative in the Preliminary Final EA (May,' 1987) continue to indicate that 4 the toe of the pile will become inundated during a flood event. The discussions on slope stability, however, still have not addressed the adverse effects on shear strengths that would result from partial flooding of the pile.
. Therefore, the comment made on the draft EA for the SIP alternative is still valid and should be addressed.
SECTION 2 Response: Page By: Date:
Plans for Implementation:
SECTION 3
(
j Confirmation of Implementation:
Checked by: , Date:
Approved by: ,Date:
i i
I i .
., . 6; d
i UMTRA DOCUMENT REVIEW FORM i
SECTION 1 f Site: Riverton, WY Date: May 6, 1987 i Document: Preliminary Final EA Commentor: NRC
]
Comment: 2 Page: 26 2 ,
} The Preliminary Final EA (May,1987) indicates that borrow site 2 would be
- used as the source of material (i.e. gravel and rock) for the Dry Cheyenne.
i alternative. During our review of the draft EA (October,1984), we noted the-possibility that this material may be contaminated since the site is adjacent to the contaminated pile. Contaminated material in this area not meeting the EPA soil clean-up standards would have to be removed and taken to the disposal i facility. This may have an impact on the availability of clean material that j would be used for the Dry Cheyenne bedding and erosion protection-l'ayers. The
- staff suggests that an assessment be performed to determine the extent of i contamination in borrow site 2, and to determine whether. sufficient quantity of uncontaminated material is available for use as gravel and rock for the Dry 4
Cheyenne alternative.
SECTION 2 .
Response: Page By: Date:
5
. Plans for Implementation:
SECTION 3 1
Confirmation of Implementation:
Checked by: , Date:
Approved by: , Date:
j
O
! :)
i j UMTRA DOCUMENT REVIEW FORM SECTION 1 j
Site: Riverton, WY Date: May 6, 1987
'. Document: Preliminary Final EA ,
j 'Commentor: NRC 4
i Coment: 3 Page: F.9, 1 2 This section states that " samples from 105 drill holes on the tailings 4 pile (including the present cover and 3 feet of material underlying the j tailings) were analyzed by gama spectroscopy..and the sample data were
- averaged to arrive at the Ra-226 concentration of 342 pCi/g." Based on a 1 review of this sampling data presented in Appendix C of the draft PSCR (June,
]
1984), it appears that the radiological characterization did not determine the -
i full extent or level of contamination. Samples obtained at the bottom of
- several boreholes show high Ra-226 concentrations which indicate that the depth
{ of contamination is greater than the depth of characterization. Additionally, a significant amount of sample data on Ra-226 concentrations at.several i borehole locations is missing. This data is needed for estimating average Ra-226 concentrations. q The uncertainty associated with the extent and level of contamination' raises two concerns. First, if the proposed alternative is relocation, then
.! underexcavation of the contaminated material is likely. If additional ,
radiological characterization is not performed prior to construction, then DOE would need continual testing of the material for Ra-226 levels during clean-up l operations to assure that all contaminated material hai been excavated.
Secondly, if SIP is chosen as the proposed alternative, then the average design Ra-226 concentration of 342 pCi/g could be underestimated which would result in
! an unconservative radon barrier design.
4 i The full extent and level of contamination needs to be determined. The staff recommends that DOE assess the adequacy of-the radiological characterization that has already been perfornied in light of these staff concerns, and determine whether additional radiological characterization of the processing site is required.
l! i SECTION 2 j Response: Page By: Date:
i
- Plans for Implementation
i i
i.
8' P
SECTION 3 2
Confirmation of Implementation:
i Checked by: , Date:
! Approved by: , Date:
i 9
s 1
5 4
4 W
4 +
l i
1 1
4 l
t 4
i
< 1 1
i-i ,
I i
9
-,-,-____-_,~,.---r-_-,a. -
.- ,7 .-,, ,,,y-. ,-
3 .. < -- r,, , , , , , - - y. , ,. ---,.,7-9., .. . , , , -,- , -- -,-r-- * +-4
. -. 1
- r 4
- , o UMTRA DOCUMENT REVIEW F'0RM SECTION 1 Site: Riverton, WY Date: May 14, 1987 Document: Draft EA Commentor: NRC/ geology Comment: 4 Page: general -
Based upon the level, of data .provided on detailed-lithology and stratigraphy of the Wind River Formation-beneath the site, staff are unable to complete an analysis of hydrogeology of the confined and unconfined aquifers. Data supporting an EA assertion that no communication occurs between the aquifers is sparse and ambiguous. For example: 1
- 1) tritium concentrations are elevated in confined sandstones (p. C-109)
- 2) the te~xt attributes errors to sampling and analytical problems without correcting or accbunting for the errors (p. C-109)
- 3) data' derived from pump tests in the unconfined aquifer are acknowledged to bs unusable (p. C-145)
- 4) some evidence suggests tailings are a source of pollution in the unconfinedaquifer(p.C-159)
More ' detailed information'bn, lithology and stratigraphy of the Wind River Formation should be collected before a final analysis of its relation to site hydropeology is completed. These; data could be derived from further drilling and coring, inspection of outcrops in the field, laboratory grain-size and petrographic analyses, and. published geological literature.
1 SECTION 2 ,
Response: Page By: Date:
J Plar,s;for Implementation:
\ .c :
ss s
.g $