ML19291C380
| ML19291C380 | |
| Person / Time | |
|---|---|
| Site: | 02700039 |
| Issue date: | 01/09/1980 |
| From: | Rolonda Jackson Office of Nuclear Reactor Regulation |
| To: | Rich Smith NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| NUDOCS 8001240320 | |
| Download: ML19291C380 (13) | |
Text
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January 9, 1980 MEMORANDUM FOR:
R. Dale Smith, Chief Low-Level Waste Licensing Branch Division of Waste Management FROM:
Robert E. Jackson, Chief Geosciences Branch, DSS
SUBJECT:
REVIEW 0F INTERAGENCY TASK FORCE REPORT ON THE PROPOSED DECOMMISSIONING 0F SHEFFIELD NUCLEAR WASTE DISPOSAL SITE PLANT NAME: Sheffield Low Lev'el Waste Treatment Facility DOCKET NUMBER: 27-39 TAC NUMBER: 4475-53 RESPONSIBLE BRANCH: Low Level Waste Licensing Branch, K. Dragonette, LPM STATUS OF REVIEW: Complete In response to your request dated October 26, 1979, we have reviewed the Interagency Task Force Report on the Proposed Decommissioning of the Sheffield Nuclear Waste. Disposal Site, dated September, 1979. This review was made by S. Wastler and O. Thompson of the Geosciences Branch.
Thereportprohidesagoodoherhiewofthestatusofthesiteandtheneeds with respect to decomissioning. With the understanding that much detailed work by numerous experts is needed for the development of decommissioning procedures, we have attached to this memo some comments, suggestions and objective criticisms.
This response completes our current rehiew of the Sheffield decomissioning.
We recomend you consider the enclosed recomendations before directly incorporating sections of the task force report into a preliminary EIS (Environmental Impact Statement). Please contact 0. Thompson.for clarification of these comments. We anticipate no significant further involvement by Geosciences Branch personnel in this project.
&w du obert E. Jacksptf Chief Geosciences Bran h, DSS
Attachment:
As stated cc: See next page 1795 190 8 0012 40 3 m
R. Dale Smith cc: w/o attachment F. Schroeder J. Martin cc: w/ attachment J. Knight L. Hulman W. Bivins K. Dragonette G. Turi L. Heller
- t. Reiter S. Wastler
- 0. Thompson PDR 1795 191
PROJECT NAME: Sheffield Low Level Waste Treatment Facility DOCKET N0.: 27-39 TAC NO.: 4975-53 RESPONSIBLE BRANCH: Low Level Waste Licensing Branch, K. Dragonette, LPM
SUBJECT:
Review of Interagency Task Force Report General Comments The relatihely new concept of decomissioning has generated terminology which is new, used in unusual contexts, and misunderstood; We suggest that certain aspects of decommissioning need to be clearly defined. We suggest the following definitions should be considered.
Decomissioning:
the process of changing the site from an operating burial facility to non-operating facility which is subject to long-term custodial care by a responsible institution and which will require minimal routine maintenance and monitoring.
Operating Maintenance: Operating Monitoring:
those functions performed atoronthesitewhilethesiteisactihe--thatis, while burial operations are active, or.at the termination of burial operations until the site is decomissioned.
Custodial Maintenance, Custodial Monitoring: those functions performed by the institution responsible for long-term custodial care of the decomissioned site. By definition of decommissioning, such activities should be minimal.
Decomissioned Site: A site for which decomissioning requirements (as laid out in the decomissioning plan) have been met and the long-term custodial care has been assumed by a resp.onsible institution.
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- Custodial institution: A responsible institution which assumes long-term custodial care of a decomissioned site, in this case, IDPH.
Decomissioning Requirements:. Those changes in the physical characteristics ofthesiteandintheactihitiesatthesiteneeded before the site is suitable for custodial case. The decommissioning requirements should be documented in a decomissioning plan.
Decomissioning Objectihes:
those conditions which will assure the protection of public health and safety for (--some specified number) of -- ) years while minimizing the amount of custodial care (custodial maintenance and custodial monitoring) required by the custodial institution.
Other terminology which may require definition includes decommissioning plan, operating site.
Our coments on the text of the task force report are discussed below.
Disclaimer The second paragraph states "We have freely endorsed or rejected thoughts-and ideas offered by others.
We recognize that this statement is valid for the task force report but recommend that such an approach should not be followed in the development of an EIS or a decomissioning plan.
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3 I.
Introduction and Purcose This section contains a good summary of the regulatory proceedings to date. At page 7, last paragraph, the purpose is stated as:
a) define current status of site b) define current knowledge of site c) outline options for decommissioning the site Item (a) has not been covered in detail and we suspect that it was not the purpose of the task force. Rather, the fact that the site is currently not in a satisfactory condition has been highlighted with examples in Section III of the task force report. Item (a) is judged to be necessary and in our perception would include (for geosciences aspects) definition of items such as those outlined in Section D of our August 20, 1979 memo (Status of Review - Geotechnical Engineering and Geology, from R. Jackson, GSB, to D. Smith LLWLB). For example, the existing topography is not known but to obtain this information will simply require a topographic survey. Our list of items in the reference is not exhaustive and the need for additional information will arise as the development of the decommissioning plan progresses.
Items (b)and(c)arecoveredinSectionsIVandV,respectiYely,ofthe task force report. Our coments on these sections follow.
II. Decomissionina Objectives The process of decomissioning needs to be clearly outlined as:
a) establishing decomissioning objectiYes b) determining wiiere and why the objectihes are not met c) designing how these deficiencies can be mitigated (decomissioning requirements) d) establishing who will perform the tasks necessary for decomissioning.
We suggest that decomissioning objectives and decommissioning requirements should be identified separately, as implied by our suggested definitions.
We perciehe the decomissioning objectives to include:
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, (j) to clear the site of operational equipment (item 2)
(ii) to transfer responsibility to the custodial agency (item 3)
(iii) to prohide acceptably low present and future gamma radiation (item 4)
(iv) to prohide acceptably low present and future radionuclide migration (item 5)
(v) to have stable surfaces and. drainage conditions which require minimum maintenance (item 8)
(vi) to ensure no degradation of the site or wastes due to the adjacent chemical burial (item 11)
(vii) to transfer all records to the custodial agency (items 12 and 13)
(viii) to prohide a buffer zone (item 14)
(ix) to physically secure the site (item 15)
(x) to ensure that the custod'al' agency is equipped to monitor the site (items 3 and 16)
(xi) to have the site ultimately revert to uncontrolled use.
The decommissionina requirements should include those items which we now know (or believe) will enable the objectives to be achieved, and may. include (for geosciences aspects):
(i) ensuring trenches are currently above the water table (item 6) knowing that in the future this may change due to changing hydrogeologic conditions (ii) analyzing and correcting existing deficiencies (item 7)
(iii) minimizing the potential for surface infiltration into trenches by draining, grading, capping etc. (items 9, 10).
We cannot agree that any of these items (or other items) should be specified as requirements at this time.
Identifying decomissiong requirements is the major part of the development of the decommissioning plan, which is discussed 'later.
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5 Our specific coments on Section II of the task force report are:
No. 1 (page 13 ) - That waste should be buried in accordance with license conditions doesnotappeartoberelehanttodecommissioningbutrather it is a consideration for an operating site.
It may, however, be relevant to legal arguments as to who is responsible for additional work at the site.
No. 6 (page 15) - That trench bottoms should be above water table levels may, ultimately, become a requirement, but at this time we would not specify this as a requirement. For example, exhuming the waste from Trench 18 or permanently lowering the groundwater level in that area appear to be the only two options available if this requirement is enforced. Neither of these options may be suitable in the overall decommissioning plan.
No. 8 (page 16) - This statement places emphasis on the " elimination of the needforactihewatermanagementmeasures...". We recommend that emphasis should be on minimizing the need because it is not technically possible to eliminate active water management for 100-200 year _s.
No. 9 (page 16) - The beginning of the statement is confusing "The conditions for potential for water.."
Is there a typographical error?
No.10 (page 17) - This statementis a means of accomplishing objective No. 9, not an objective itself. Also the difference between " eliminate" in No. 9 and " reduce" in number 10 should be more fully discussed, then clarified.
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- III. SiteStatushersusDecommissioninoObjectihes Our general coments regarding this section are discussed under Sections I and II, above. Weagreewiththeexamplesprohidedandemphasizethatadditional deficiencies probably will be revealed after the current status of the site iscompletelyestablished(seeourdiscussioninSectionI,abohe).
Our specific coments on Section III the task force report are:
No. 7 (page kS) - rehise coments to read ".... new ehidence suggesting that the sand lenses under the site may be continuous raise the major issues with respect to this criterion. Groundwater maybemohingfasterthanexpectedduetocontinuityof the sand lenses..."
No. 8 (page 16 ) - we suggest that the goal should be stated as minimizing the theneedforactihewatermanagementratherthaneliminating.
No. 19 (page 17 ) this is redundant considering item 9 (d).
IV. Present Understanding of the Site Introduction Page 20, line 3 *understoo'J and controlled for extended periods of time (i.e.100-200 years). Radio-nuclides can be.." Add the underlined as shown.
Page 20, paragraph 2, line 9 - The wording ".. with a significant potential..."
leaves the meaning open for various interpretations due to the relatihenatureofthewordsignificant. The statement should be specific and define what is needed. The use of probabilistic arguments should not be dismissed without careful consideration.
Page24,secondparagraph,line2-Thestatementismadethat"...holuminous quantities of radiological, geological and hydrological data areahailableandhaveorarebeinganalyzedandcorrelated."
Contrarytotheabohestatementweconsider ai'a 1 geo-
l logic data to be minimal. Additional questions and comments hahebeenmadebythestaffwhichhahenotbeenanswered by NECO.
Further ccmants in this section are restricted to geosciences aspects (partsB.SiteGeologyandC. Hydrology).
B.
Site Geology The need for a thorough understanding of the site stratigraphy has been expressedinourprehiouscorrespondence(e.g. August 20,1979 memo).
The USGS report referred to in the task force report (page 59, last paragraph) mayprohideanadequateanalysisofthestratigraphybuttheUSGSreportshould be reviewed in detail by NRC.
The sub-paragraph " Geology of the Site" is accurate but we recommend that a more detailed description of the geologic histcry should be included. The complexity of the site stratigraphy and the problems resulting therefrom are the result of recurrent glaciation, erosion, weathering and deposition since the Pennsylvanian Period. Thus we suggest adding to this sub-paragraph or including a separate paragraph on geologic history. The licensee's stratigraphic study (January 23,1979) prohidesagoodsummary-perhapsinmoredetailthanrequiredforthetask force report. We suggest the following outline should be followed:
PennsylhanianPeriod(300mya-millionyearsago)
Late Paleozoic through Early Quaternary Period (300 mya to 1/2 mya)
MiddleQuaternaryperiod(lessthan1/2mya)
Illinoian Stage Sangamon Stage Wisconsin Stage Holocene Period (recent)
The sub-section " Geology of Surficial Materials" presents detailed geologic descriptions of the surficial soils (although the Sangamon stage Berry ClayismissingfromFigureIV-6). We suggest that the geologic descriptions presented should be condensed and this subsection should be supplemented with engineering details. The geology is important for understanding the site, buttheengineeringdetailsaremorerelehanttositebehavior. For example, sands of similar permeability will transmit water in a similar manner irrespectihe of their geologic origin. The soil properties can be used to quantify erodability slope stability, consolidation etc.
The sub-section " Bedrock Geology" could be better described as " Bedrock Hydrogeology."
We have no comments on the USGS Research Study at this time. Howev'er, we recomend that the results of the study should be reviewed in detail by NRC so as to be sure that the site stratigraphy as described by USGS is applicable to decommissioning.
Our specific coments on section III, B, of the task force report are:
Page 48, first paragraph - the Geosciences Branch has only given a cursory review of the stratigraphy report mentioned. Based on that review, the staff determined that the report was unacceptable and did not address the basic questions resulting from the review. We do not consider the factors listed as a), b), c) and d) to be our only concerns or necessarily our major concerns.
Page 54, number 6 - Does the Hulick Till stop migration into bedrock, i.e.
do fracture and faults in site area bedrock have a completely impermeable cap?
If not, the migration of radionuclides through fractures and faults into regional groundwater system needs to be considered.
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. C.
Hydrology We have reviewed this section as it relates to geology and geotechnical engineering. ThehydrologicaspectsneedtoberehiewedbyHydrology-Meteorology Branch.
As outlined in this section, there remain many uncertalaties regarding the hydrol'ogy at the site. We expect the USGS Report to provide some enlightenment.
However, the prediction of future changes in the hydrology will require additional study during development of the decommissioning plan. For exauple, different methods of surface treaLaent of the site will influaice the future hydrologic conditions, as implied in the last two paragraphs of section C of the Task Force Report.
The sub-seci. ion "Hydrogeology of the Site" could be incorporated in the foregoing section of the task force report " Bedrock Gaology" as indicated abcVe.
The surface hydrology is presented in general terms.
The local surface hydrology in a function of site grading which influences erosien potential.
The site-:pec fic surface hyrdology also shculd be addressed.
V.
Decommissioning Options The davelcpment of the most suitable decommissioning g hn will require careful ccasidaration of many alternatives. The task forca ca;':rt v fcccres scma of tha alternatives most of which haYe b':en discussed amongst 5.h2. 2.ff sf
.C
- c.d o';her agencies involved in the project.
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. It is our opinion that the presentation of alternatives in the task force reports is not desirable except as examples. Attemptstodevelophiablealternatives is premature at this time. The first step must be to complete the survey of existing site conditons which include the completion cf the USGS study of site stratigraphy. Following this, some'af the physical conditions which require modification can be identified. For example, only after the existing site topography is estabished can feasible grading plans be generated. Thus Alternative III - heavy mounded covers - may not be compatible with existing grades.
Th2 second step (which will be partly concurrent with stcp 1) is to consider the alternatives such as proposed in Section V.
The site presents some unusual problems which will demand imaginative solutions.
In addition to the PNL/NRC report referred to in Section IV, page 97, of the task force report, professional assistance should be obtained from other sources. We recommend that input should be obtained from consulting engineers who are familiar with the latest design and construction techniques and who, by the nature of their business, are forced to. develop imaginative solutions to problems (generally, but not always, by virture of economic considerations). Two or three competent consultants could provide independent ideas. Their reports should contain general descriptions of viable alternatives as well as estimated ranges of construction costs and maintenance costs.
We would expect the consultants to consider ways to meet the decommissioning objectives as outlined in Section II and to include the alternatives provided in Section V.
In addition we would expect consideration of many other alternatives such as:
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. (1) slurry wall cut-off trenches (2) concrete, asphalt,andsyntheticcoherschertrenches (3)reinforcedearthcoherschertrenches (4)densificationoftrenchesbygrouting,hibrating,etc.
(5)variousvegatiheandnon-Yegetatihesurfaceprotections (6)actiheandpassihesurfaceandsubsurfacedrainage VI. Sumary and Recomendations Wedonotagree,withtheinformationahailable,thattheselectionof alternative VI or VII is justified. We also do not agree with the statement that ".,< the geology and hydrelogy will be adequately understood upon completion of the USGS studies in 1981."
The USGS findings should be independently reviewed by NRC staff and/or other consultants skilled in geologic siting considerations to assess the applicability of the USGS report to decommissioning at Sheffield.
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