Synopsized Minutes, Conference on Runit Cleanup, October 4-5, 1977

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The signatures of the participants recorded on the n=t page indicate only their agreement that the summarized minutes accurately reflect the discussions, agreements and consensus reached during the conference. Any exceptions to either the minutes or to the chairman’s report by any participant are as noted below. Exceptions and explanations provided to the chairman by participants are appended to the minutes or the chairman’s report as appropriate.

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SUBJECT: Minutes of Conference 1. A conference convened at Las Vegas, Nevada, 4-5 October 1977 to examine means of meeting requirements for a more definitive, quantitative characterization of the scope of work involved in the radiological cleanup of Runit Island, Enewetak Atoll. The message convening the conference A listing of participants and observers is enclosure 2. 2. The conference opensd with introduction of participants and observers, and brief remarks by BG Grayson D. Tate, Jr. Commander, Field Command, Defense Nuclear Agency, and Mr. Roger Ray, Department of Energy, Nevada Operations Office, DOE Project Officer. General Tate stressed the overall importance of Runit in the cleanup, the necessity to obtain a better definition of the scope of work involved, and the desire to explore alternative methods of meeting cleanup requirements. Mr. Ray addressed the purpose of the conference and the possible alternative of performing cleanup of Runit first in order to determine resources remaining for use on other islands of the 3. ~~e chairman briefiy reviewed the background of the cleanup, the cleanup requirements, the plan of operations to achieve cleanup, and the specific problem relating the scope of work on Rtinitto total resources and the questioned the FCDNA position that cleanup of all soil contaminated to levels of greater than 400 pCi/g is mandatory and has priority over cleanup of contamination levels between 40 and 400 pCi/g. Mr. McCraw stated that the intent of the AEC Task Group had been to place”both conditions at equal priority so long as resources were available. LTC (P) Sanches read an extract

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from the AEC Task Group report on this subject (Encl 4). The chairman reiterated the F’CDLNAposition and the fact that resources are constrained, limiting the total amouat of work which can be done. This condition forces consideration reductig the scope of work involved on Runit and the placing of priorities tasks ccm.%ideredto firm requirements. Dr. E=nlitt reviewed the available data, how the data was obtained and showed vie=s of the island as it appeared during test operations and as it “ appears now. Printed data is at enclosure S. There were discussions of uranium contamination levels. Dr. Bramlitt reviewed the work done on the Erie test site and sampling methods used on areas of southern Runit. 5. The chairman asked participants to consider t5eflofwhat can be concluded from the available data and whether that data can lead to a better definition of the scope of work under conditions prevailing on discussions of the methods used to obtain available of preciseness of aerial survey and in situ survey. Runit Island. There were data; the relative degree The aerial survey technique integrates readings over Approximately one hectareeach second. Aerial survey isoplerh l%es are probably accurate to f 100 feet. The in situ survey integrztss over a field:af view of 69.8 feet diameter and approximately three centimezs=s depth. It was concluded that the data presently available would not support refinement of the scope of work involved. Further data is highly 6. The chairman then addressed the obtaining of such data. There was discussion of methods of measuring both surface level and subsurface contamination levels

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and the specified removal criteria. Mr. McCraw read extracts from the four removal criteria contained in the operations plan Miss Barnes stated that it would be impossible to confidence ievel of not having missed significant reach even the 50 percent without doing much more profile sampling. For example, to find a particular region of cont=ination two feet wide, under worst case with the seam parallel to the grid lines, would require sampling every four feet. To provide such characterization would require commitment of substantial resources. If the characterization is done on a simple yes-no criteria the sampling need not be so precise. Using the highest contamination level recorded on the island, 3200 pCi/g, Dr. Crites demonstrated a calculation showing that a pocket of contamination which would average greater than 400 pCi/g over a 21 meter (68.8 ft) field of view would be approximately seven meters in diameter. Thus sanpling on a grid of less than seven meters should locate such a minimum pocket size subsurface contamination of interest. There was discussion of the one half distance technique for determining the presence or absence {yes-no) of subsurface contamination. Available data indicates only a few sample locations showing subsurface contamination at greater *n 400 pCi/g levels. Sample locations are spaced on approximately a 200 foot ~rid. Moving one half the distance between greater than and less than sampie points iteratively should provide boundary definition of contamination areas of interest. This investigation would be limited to those areas where available data indicates high subsurface contamination levels, thus reducing the effort involved. The “7 meter” criteria would set the lower bound of the iterative half distance.

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7. There were discussions of techniques for taking profile samples centered primarily on advantages of backhoe versus auger. During the Erie test area investigation 40 sample sites were completed in about 10 days using the backhoe. -rr~s~= accomplished in spite of the delay imposed by operating in anti-crnz=irtation clothing as required by rad–safe procedures. It ~-a.s concluded that the backhoe was probably faster and provided more precise 8. The chair requested participants to address the northern half of Runit as three distinct areas, the cactus crater area, a central area, and the Fig/Quince area, and what sampling should apply to each. <actus area, showing high levels of subsurface The consensus was that the contamination should be treated vicinity of locations showing high subsurface contamination. The background history of the central area provides no reason to suspect high subsurface contamination in that area. Therefore, sampling in this area should be limited to a iew confirmatory samples sites in areas not covered by the available data. (This probably amounts to something on the order of 20 sites or less.) 9. The ejects (lip) of cactus grater presents a special problem. Past history and available data tend to indicate that there may be high subsurface contami nation below-the pre detonation surface level, This level is now buried under the ejects. This condition lead to a brief explanation of the cratering operation and the possible extent of the area to be covered by the entombment. Consensus wzs that this area should be considered after a better knowledge of the extent of the area to be covered is gained, If the area is to be covered by cement/soil mixture no further sampling is needed. If it is not to be covered, then sampling should be done to confirm presence or absence of

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greater than 400 pCi/g contamination levels, both in the ejects and below the pre-detonation surface. Disposal would be by spreading, for levels less than 400 pCi/g, or crater containment for higher levels. 10. The method of analysis of samples was discussed. It was agreed that a gross alpha count was probably the fastest and simplest method to obtain the yes-no answer sought. This would not define the isotopic contamination content but”woul~ provide a base to be supplemented by radio-chemistry analysis which would provide the isotopic content and should be correlatable to gross alpha count for any specific discussed included the to sampling increment to be utilized. Increments averaged 10 centimeter depth used for most of the available data; averaged 20 centimeter depth, based on a nominal 6-inch cut capability for a dozer; and 20 cestheter increments with a specific 5 centimeter sample from each increment. The operations plan specifies 5 cm sample depth because past experience at Xsva2a Test Site has indicated that averaging samples of greater depth leads to ancmolous data output. Five centimeter depth samples will be the bases for certification of the condition of the islands upon comple~lcn 05 cleamcp, Discussion included the advantages and disadvantages of horizor.:d averaging versus vertical averaging for sampling. Consensus favored ve=tical averzging. Discussion also laboratory to analyze the samples produced. 150 samples per day for gamma scan and gross included the capability of the Naximum capability would be about alpha count plus about five percent radiochemical analysis. This level would not permit support of other operations. Other operations could be supported at levels of 50 samples per day-input. It was agreed that garmnascan of samples at the laboratory could be used to select samples for analysis. Only the “hot” samples would be analyzed. Other

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samples would be held for future use depending on the outcome of the “hot” sample a~-alysise This technique was favored over using gaumiascan on sample site sidewalls and only sampling ‘“hot””areas. This concluded the first day’s

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incremen.ralsampling techniquesdiscussed and proposed adoption of 20 cm sampling increments wirh a d.&crete 5 crn sample to be taken from each may also nreet some certificationrequirements. The proposal was accepted. chair requested the group consider depth to which sampling should . Consensus indicated that a depth of 120 cm generally will suffice but that the option to go deeper should be left to field personnel. It may be particularly desirable to go to greater sampling depths in areas of ground C(2zeros, in bu# or mound areas, and in ejects areas n=r qfctus crater. The backhoe may not suffice for some of these depths (greater than 10 feet) other ~uipment may be required. Discussion reverted to the sampling grid to be used for characterization. Church proposed, for consideration, a 10 meter grid for the “bet” ar-s (Fig/Quince and Cactus Crater areas), and a wider spaced grid for the “clean” area in between. Several members indicated their support for the half dlsta.nce technique for initial exploration with grid size to be decided later based on data obtained from initial efforts. This leAtJ to extensive discussion of desire for data versus reasonable expenditure of resources and purpose and extent of characterization. The chair main?ziined that characterization should be limited to determining the extent of known subterranean pockets and the extent of surface contamination arws. The effort should not extend

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to exploration to locate other possible subterranean pockets. Mr. Church stated that the available data was not extensive enough to support a contxmtion that other -pockets did not exist= For purposes of certification there would have to be ~dditional data mken. The same method of {Jb@hhIg data for certi.ficaticm applies to all islands. This consists of in-.%& and surface soil sample su~eys, and investigationof suspected burial sites, supplemented by selected soil profiling data. Obviously, the greater the density of soiI sampling profile data, tie lower the chance of being surprized later in the After extensive discussion, the folIowing was proposed and accepted The northern half of the island will be gridded on a 50 meter grid. The “cool” area will be sampled firstin order to characterizethe areas to be used for stockpilingof soiland debris from other islands. Approximately 16 to 50 sample sites will be required, depending on initialfindings. Areas are to be decided bsed on stockpilelocations. Sampling transectsshould be cut through the mounds in this area to characterize the contents thereof. Charac&riition of the extent of subsurface pockets can use an adaptation of the one half distance technique, working along the 50 meter ‘grid lines. Densily of other sampling in the “hot” areas can be decided on basis of data obtained from the “pocket” investigation. Use of the standard 50 meter grid will permit use of during characterization for consideration for certification.

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will be no different in method for certification, the history of the island and available data do indicate a probable requirement for higher dens i!y survey t&n may be required for other islands. This led to a discussion of the advantages and disadvantages of placing contaminated stoclcci.les on .- ~. relatively uucomarninated areas. It would generally be better to put contaminated stockpiles in areas known to be contaminated to similar or s higher levels. The “cool” area requires relatively few sampling sites and to place the contaminated stockpilein the “hot” area may interferewith the 15. It was agreed tit when resources permit it would be highly desirable to use one MB to further refine the area of surface contamination to be removed. These arms are defined, in the Fig/Quince Area, by aerial survey contours. The Cactus Crater area is not defined. La-= survey refinement would assist considerablyin refiningthe estimates of area, and move in toward hot areas and define the periphery of those areas over 400 P c~g. This would not be a fullsurvey but would refine the area boun&ies and would avoid risk of high contamination of the “Itifi There. was discussion of use of this “peripheral” technique as compared to a full survey. It was agreed that the peripheral technique would not totally define the surface artxi but certainly should provide better estimatingdata than the

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aerial survey. Used on the grid lines the characterization effort would be directll applicable to the full survey for certification and, thus, is not wasted be used to search the Fig/Quince area for very ?WXT and field instruments “chtm&”. Removal of such spots, by shovel and $=ing techniques, could , contribute m=sunhly to reducing the areas measured to be over 400 P ci/g survey. It appears This ‘&uld be done prior to soil profiling and in-&- that the overlap period for FRST members would be an to conduct this effor~ ltwould contributeto training with a meaningful effort. This may also apply to soil 17. ,’The question was raised whether soil profiling in known hot pocket areas would disturb the validity of tie in-= survey. It was concluded that it probably would not. It would be desirable to perform the in-SLY survey before soil profiling but this is not an absolute necessity. “Hot” piles from soil profiling can be shielded from the lfl~, view.

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18. The cost in resources and time required was a#’essed. It was generaliy zgreed that these costs can not be accurately assessed at this time. Density of profiling efforts and of the in-situ survey effort depends, to some extent, on the initial data obtained. Howev= , the effort does not appear to be excessive. Additionally, as proposed for conduct it largely contributes directly to effort requi?ed anyway for certification. This only minimal resource expenditure is devoted exclusively to the characterization effort. The efforts which may not be directly contributory are the delidination of the subterranean pockets and the FRST pick up of 19. Mr Doles ask what priorty would be given to this characterization operation. He indicated that without some priority the operation would be only sporadic and require a long time. The chair replied that this operation should receive the same priority as the beginning of cleanups on Le.yorand Boken. Hopefully assets available would permit simlt.aaeous work on cleanup and characterization. Mr. Doles expressed concezz that …