Title : AMANDA science project at South Pole Type : Antarctic EAM NSF Org: OD / OPP Date : June 23, 1993 File : opp93109 AMANDA Environmental Impact Assessment AMANDA or the Antarctic-Muon-and-Neutrino-Detector-Array would be one of the first experiments designed to do neutrino astronomy. AMANDA's challenge is to map the skies to locate neutrino sources, just as early astronomers used ordinary light to map the stars in the sky. AMANDA would be a first of its kind experiment. AMANDA's impact on the environment can be broken down into four distinct divisions: 1. Installation of the AMANDA photodetectors into the ice. 2. Operation of the AMANDA photodetectors in the ice. 3. Operation of the above-ice AMANDA experiment. 4. Eventually decommissioning of the AMANDA experiment. Items 1, 2 and 4 are referred to in the text as "below-ice" items and as such require special considerations. Item 3, is referred to in the text as "above-ice". We will see that AMANDA presents the same environmental considerations as many of the experiments now running at the South Pole. Proposed Activity AMANDA would detect neutrinos by measuring the light signals produced by the collision products that neutrinos occasionally produce as they travel through the ice. Because these neutrino collisions are exceedingly rare, very large volumes of pure, clear, dark ice or water have to be instrumented to produce even the most modest of results. As far as detection media go, usually only water or ice can be found in the large volumes required for this research. South Pole ice has three immediate advantages over water: 1) it is a stable solid platform which simplifies deployment; 2) it has no radioactive potassium content; and 3) no bioluminescent life-forms that will emit light that will disturb the photodetectors. AMANDA's observations are best conducted in a pure-ice environment. AMANDA would monitor these large ice volumes by placing light sensitive detectors about 1100 meters deep into the south pole icecap. AMANDA would be basically a non-polluting activity. The detectors would be totally passive, and there would be no interaction between the detectors and the ice. Light is collected by sensitive instruments, but these instruments require only minute amounts of power, about one watt each, and have no waste products. The instruments would run at the normal ice ambient temperatures. Ice clarity is of the utmost importance for the detectors successful operation. Holes 50 cm in diameter and 1100 meters deep would be drilled into the ice to allow the detectors to be installed at depths between 900 and 1100 meters. A cable carries signals from the detectors up the hole to the AMANDA experimental building on the surface. The holes would be drilled using hot-water. During the drilling operation the hot-water hoses would pass through a sheave mounted on a temporarily installed 15 meter high tower. The hot-water technique yields a borehole 1100 meters deep filled only with near freezing water. The impact is momentary in that the water in the hole will freeze back in about 24-36 hours. It is during this period that the detector modules are inserted and allowed to freeze into the ice. It is judged that the AMANDA surface station would present no unusual environmental impacts, and its operation should be like any other South Pole activity that involves people. In fact, we plan for a largely remote operation, requiring only a minimum technical staff to be present on site. We note that the total impact would be slightly greater than what is currently under way with the prototype experiments now being carried out. Project Location AMANDA would be located at South Pole Station. For optimal detection, it has been determined that clear bubble-free ice with visible light absorption lengths greater than 24 meters are required. This bubble-free ice appears at about 800 meters depth at the South Pole, and though other locations such as Vostok or Dome Alpha have bubble-free ice at slightly more shallow depths (700 meters) none of these places can offer the needed experimental support infrastructure that South Pole Station can. Further, if AMANDA were to be built in Greenland, then one would have to go to depths of 1300 meters or more to find comparable ice quality. South pole ice is also about the coldest ice on earth with temperatures continuously near -50 deg C, which means that the AMANDA photodetectors would be much less bothered by thermal noise. Again only Vostok ice is colder, about -55 deg C, and Greenland ice is quite warm, about -31 deg C. South Pole also offers circumpolar viewing of neutrino sources, the unique advantage that neutrino sources never "rise- and set" but always appear at a constant angle with respect to the earth's rotation axis. Even a neutrino telescope, which looks through the earth, benefits from this feature. Finally, South Pole Station provides the infrastructure necessary to support an experimental effort of this magnitude. Alternate locations on the south polar icecap would require LC-130 Hercules aircraft support and construction of life support facilities. Current plans would call for the AMANDA array to be approximately centered around the AMANDA/CARA building which is located in the new astrophysics or dark/quiet sector across the runway about 1 km grid WNW from the current station. This location is far enough from the main base to minimize adverse effects on observations from electromagnetic interference, but close enough to allow safe and convenient daily access throughout the year. In Figure 1, we give the current site development schedule and in Figure ,. we show the current site plan for the AMANDA/CARA laboratory and the location of the AMANDA detectors in their 1 + 9 configuration. The central borehole would be located about 10 meters grid-West of the AMANDA laboratory. The other nine holes are located in a circular pattern with a radius of about 100 ft. This plan is shown in Figure 3. which gives a magnified view of the AMANDA experimental area. Plans would call for 6 of the holes to be drilled this 93-94 season, with the remaining 4 holes being drilled during the 1994-1995 season. Project Requirements Current plans would call for the AMANDA project to be housed in the top floor of the new AMANDA/CARA building, a two-story elevated building with a 9 by 17 meter footprint, located across the runway from the dome in what is now called the "dark sector" or astrophysics sector (see Fig. 2). It would be extensively used during the austral summer, and used by the winter-over operator watching AMANDA during the austral winter[1]. Access to the site would be by foot and by vehicle. Future plans would call for access through a new tunnel. Travel levels of about 16 person-trips per day in the austral summer and four- person-trips per day in the winter. The AMANDA experiment must be protected from interference that might be generated by other activities at the base, such as electromagnetic interference from vehicles, and transmitters, hence its remote location. Current plans would call for electrical power and data and communications links to be provided by buried power and fiber optic links connecting the astrophysics sector to the main station facilities. The total power consumed by AMANDA would be about 3-5 kW, and this power would be used to run the "above-ice" data acquisition electronics in the AMANDA building. The total amount of "below-ice" power amounts to about 1.0 watts per detector or a total power dissipation of less than 200 watts throughout the entire under-ice array. Because the experiment is "almost" self-monitoring, only a moderate human presence would be required at the AMANDA site. During winter operations, only the AMANDA winter-over would be present, while during the summer months we would expect an average, three-four people. Project Schedule Current plans would call for the construction of the AMANDA laboratory in the new AMANDA/CARA building and the drilling of the AMANDA holes to start as soon as possible after the November 1, 1993, station opening. AMANDA is scheduled to occupy the new AMANDA/CARA building about January 10, 1994. In this case the experimenters would have about one month to get the experiment set-up and prepared for 1994 winter-over operation. During the building period, the AMANDA testing would proceed in a Jamesway tent temporarily located just grid-West of the new building. Hot-water drilling would be done by the Polar Ice Coring Office (PICO) and would proceed at a rate of about one-hole per week starting sometime after November 20, 1993. This allows for a two-three week setup period. Plans would call for drilling six holes this 1993-1994 season. The five holes located grid-West of the AMANDA building would be drilled first so that the drilling operation would not conflict with the construction of the laboratory. The central hole near the laboratory would not be drilled until after January 10, 1994, when work on the building had been finished. AMANDA's normal operation will be in a totally-passive mode. It will not radiate any electromagnetic signals, emit any light, or heat, or other pollutants into the environment. At times, however, the phototubes would be calibrated with a small laser. The laser would run for 20-30 minutes and its light would be conducted entirely within a shielded fiber optical cables and directed down one km deep into the ice to the phototubes. The total power radiated into the ice will be milliwatts. AMANDA operations should not affect any other scientific activity at the station in any measurable way. Its personnel would not be required to enter into any restricted areas, such as the Clean-Air sector. The only measurable impact AMANDA will have on the South Pole Station will be during PICO's hot-water drilling operation. This drilling however, is being done one km away, and almost "down wind" of the clean-air research (See Fig. 2. for details). Because AMANDA's drilling operation is estimated to pollute the air at the same rate per day as the power-plant for the two days/week that drilling occurs, and because is located about two-three further away than the station's power- plant, we believe that AMANDA's drilling operation will have no effect on the Clean-Air Facilities operation, or any other South Pole operations. Impact on Environment The South Pole Station is located on flat terrain about 3000 meters (10,000 ft.) above sea-level. It is featureless terrain except for the man made structures already in place. AMANDA's above-ice activities would use new structures that are in the same character as those already there, and the impact would only be incremental. There are no Antarctic wildlife or plant species at this site. Because the above-ice activities involve only electronic signal detection and processing, they are benign or transparent to the environment. Any toxic or hazardous substances associated with the AMANDA operation, such as cleaning solvents used for the maintenance of electronic equipment, would be used in only very small quantities (measured in pints and ounces) and would be removed from the site when their intended use is complete following the established U. S. Antarctic Program procedures. No such substances would be disposed of at the site. The drilling activities require special attention. A plan view of the hot-water drilling operation is shown in Figure 4, and an elevation or "down-hole" view of the operation is shown in Figure 5. Drilling each hole requires approximately 1.25 megawatts of heat and 100 kilowatts of mechanical power to drive numerous pumps and heaters. Normally we would burn JP-8 to fulfill our energy needs, however, during the 1993-94 season, our energy needs could be almost entirely supplied by using some of the 25,000 gallons of "old" diesel fuel that was the emergency camp fuel supply [2]. As a result of using either JP-8 or diesel fuel, there would be air pollution. There is also the potential for spills of fuel and of the ethanol which is used as an antifreeze to purge water from the drill system when it is not in operation. A study was undertaken to determine which drilling method would most efficiently provide the 50 cm. diameter holes to a depth of 1100 meters. Specifically, mechanical drilling techniques were investigated since the specific energy required to remove ice mechanically is one-hundred times less than thermal means. However, the energy required to remove chips and provide water to cover the instrument string is nearly equal to the hot water technique. In addition, the cost and weight of a pipe- driven drill system precludes its use in the current ten hole program. Hot water would be the drilling fluid of choice since it matches the surrounding medium once it refreezes. Any thermal disturbance would be dissipated in the -50 deg C ice given the current drilling rate of five-ten holes per year. Use of other fluids to fill the boreholes would present an unrealistic logistics burden requiring over 50,000 gallons per hole compared to a fuel use of 3000 gallons per hole. The need for 1-1.25 megawatts of heat would require burning about 40 gallons of JP-8 fuel per hour. An additional 15 gallons per hour would be required to run the pumps and supply electricity. Burners would be tuned and derated for altitude (pole is at 3000 meters) to provide maximum efficiency which would also minimize combustion by-products. Additional measures have been taken to maximize heat transfer to the water by adding additional coils in the heaters. High-pressure pumps would be run with standard diesel engines. At a drilling rate of 0.5, meters/minute it will take about 36-40 hours to drill an 1100 meter deep borehole. During that 40 hour period the fuel consumption will be about 55 gallons/hour or a total fuel expenditure of about 2200 gallons. In a similar period the station burns about 1900-2000 gallons (figured at a station consumption of 1150 gallons/day during the summer months [3], so that over the two day period need to drill one borehole, PICO operations will burn about the same amount of fuel that the station burned in a similar period. At a rate of one hole per week, we find that PICO consumes 2200 gallons to the stations 8000 gallons or about 27% of the station's consumption. Over the 3and 1/2 month summer season, we find that PICO would consumes 14,000 gallons to the stations use of 115,000 gallons, so that PICO's use would be about 12% of the station's normal usage. We can thus say that the integrated air-pollution effect of the PICO hot-water drilling operation is about 12% of what the station itself contributes to the atmosphere during the austral summer period. The pollution from LC-130 Hercules flights can also be estimated. At 160 flights/season with an average time on the ground of 30 minutes, and using a burn-rate of 400 gallons/hour we find that LC-130's burn about 30,000 gallons of fuel while "on-deck" at the pole. This estimate does not include take-offs and landings. When you include this contribution, you find that PICO then adds only about 10% to the South Pole Station's total air pollution budget. The potential for spills would be minimized by using closed system manifolds to transfer fuel directly from bladders or drums to the engines and heaters. In addition, secondary containment fixtures would be used. Pans could be placed under storage units, generators, and in the transfer areas. In the case of an oil or fuel spill we would follow the instructions set forth in the South Pole Oil Contingency Plan [4]. Anti-freeze must be used to prevent water from freezing in the hoses and heaters of the drilling system when not in use, and to pre-heat the drill system prior to adding water. Ethanol would be the preferred fluid in the event that some fluid is lost during the water-purge process, since it is a naturally occurring substance which evaporates readily even at low temperatures. Glycols with rust inhibitors are considered unacceptable since 150 gallons are required to fill the system. Use of compressed air to blow the system out is not an option since too much water remains trapped which subsequently freezes. As mentioned briefly earlier, current plans for the '93-'94 and '94-'95 drilling operation would call for us to use the 25,000 gallons of "old" diesel fuel that was the emergency camp fuel supply. This old fuel is now of inferior quality, due to its age, and makes its use as fuel for aircraft or emergency generators questionable, if it is not used on-site as proposed. This fuel would eventually have to be flown back to McMurdo at an expense of an additional 40,000 gallons of fuel used by the aircraft. We may also be able to use oil that is changed from the station generators and other engines to provide oil as required for the pump fuel mix. While oil is less than 1% of our fuel requirements, we have to add oil to any JP-8 used to give it some lubricant property to prevent pump failures. Samples of oil from the station generators would be analyzed at the McMurdo Station Laboratory or another laboratory to ensure it meets required standards before it is combusted. Safety and Health Concerns We would operate within all guidelines of the regular South Pole Station operations regarding safety for both personnel and for the environment. Concerning the specifics of the drilling program, several issues arise. PICO has been involved in many hot-water and other drilling programs since 1977 without injuries. The major safety issues are: 1. hot-water, just below boiling (90 deg C) flowing at 50 gal/min at 65 atmospheres of pressure. 2. an open-hole 60 cm in diameter with a 40 meter drop to the water at freezing (0 deg C). 3. potential pinch points between cables and other objects. 4. rotating machinery 5. electrical circuits 6. 15 meter high tower Pumping water that is near its boiling point at 50 gal/min under high-pressure has the potential of causing severe injury if there is a catastrophic failure of a hose or other piece of equipment in close proximity to a person. The capability of all hoses and pressure vessels exceed operating pressures by a factor of 6. All hoses and other hardware are rated for use at the low ambient temperatures encountered at South Pole. Because this is an industrial process, several safety valves, low-flow shut-offs, and many other devices are incorporated that would shut-down the system if temperatures or pressures get too high. Specific "weak-points" are built into the system that provide automatic shutdown if all else fails. The "open-hole" issue is addressed by covering the hole with a grate that would not allow anyone to fall through it during the drilling operation. During periods when the grate is removed, such as raising or lowering the drill or installation of the detector strings, personnel working around the hole would be wearing safety harnesses. Potential "pinch-points" and rotating machinery would be covered or roped off. Emergency shut-off points would be provided near the winches and the hole. All PICO electric circuits are restricted to 220 VAC which does not exceed normal household operating voltages. We believe that the normal protective circuitry combined with emergency shut-off points at activity sites would cover this area adequately. Presence of a 15-meter tower would require the use of hard- hats when work is going on overhead. Finally, a training program for all personnel who would be working with the drill system is a standard procedure. The nature of this type of drill dictates that we start off with a small system and gradually work toward the full operational system, so everyone understands the operational procedures from first principles. We believe the setup procedure evolves slowly enough so that everyone receives adequate hands-on training. Half of the drilling team would be made up of returning staff. Recommendations for an Expanded Program While we feel that we have prepared the most efficient and cost-effective program for the current ten string deployment, if the program is to continue it may be beneficial in the future to consider the following options: Turbo-supercharging the electrical-generator engines would benefit performance and decrease unburned fuel in the exhaust. We strongly recommend that this step be taken, however, the cost would be $30,000 to $50,000 to produce a pump that can be compared in performance to the ones we currently have. A test of this type of unit would provide baseline data allowing a retrofit of all existing generators operated at altitudes above 2000 meters. PICO would have to receive an "OK" to proceed by July 1, 1993 to conduct the test late this season at South Pole Station. We recommend considering solar concentrators for supplying heat and electricity if the project continues beyond the presently scheduled ten holes (See attached paper) [5]. We suggest a solar trial run using a small system first,because solar has the greatest potential to lower the total fuel consumption for the project, but it has a three year development time. To pursue this program, we recommend purchasing one or two sets of solar panels to obtain data on how to proceed with a larger system. The estimated cost of a smaller system (800 watts electric, and 3200 watts thermal) is about $25,000. Finally, none of the equipment is expendable, and all equipment would be returned and used on other projects. In the future the system of JP-8 fired boilers would be used as a backup for cloudy days when and if the solar option is used. Equipment already at the South Pole would be fully used within the current drilling scheme. Decommissioning Impact All of the above-ice structures and equipment that are to be constructed or placed at the site are removable, such that at the completion of the project, no lasting damage to the site shall have been incurred. The impact on the environment should be measured by the number of people present, rather than by the nature of the experiment. The number of people, seven to eight during the summers and one winter-over, is a small increment to the current level of both summer and winter personnel. It is judged that AMANDA's long-term impact on the icecap would be negligible. The photodetectors are constructed entirely from inert materials, and are mostly glass, with a small number of passive electrical components (small resistors, etc.) enclosed inside of a glass benthosphere. The amount of heat introduced into the ice while sizable is in reality negligible when you consider the size of the heat sink that is available during the 36 hours needed for freezeback, and the length of time between drilling each hole--one week. Ice experts, such as Dr. Charles Bentley, University of Wisconsin-Geophysics, have been consulted and they assure us that the strain on the ice is minimal [6]. Transverse strains should be non-existent which means that the cables that carry signals to the surface would not be sheared off, and longitudinal stresses should also be very hard to detect. All of the below-ice structures and equipment that have been installed at the site are also removable, but not as easily as the above-ice structures. Water is the most benign and by far the cheapest fluid we can use to fill the boreholes. The only problem posed by using water in the holes is that once it freezes the photomultiplier strings are trapped. To remove the strings would require about four times the amount of fuel needed to originally install them. This removal technique would also result in four times the amount of air pollution issued during installation. This is because the original diameter becomes the new hole radius and the heat needed goes as the cross-sectional area of the hole. Because the photomultipliers are 98% glass by weight with no toxic components and the cables are polyethylene, our recommendation would be to leave the strings exactly where they are. South Pole ice-flow is such that in geological time- spans (100,000 years or more) the inert string components will be eventually discharged into the Weddell Sea through the Ronne Ice Shelf [6]. Methods to Detect Environmental Harm All AMANDA and PICO personnel will operate within all guidelines of the regular South Pole Station regulations regarding safety for both personnel and for the environment. Recommendation In light of the information provided above, the preparers of this document recommend that the NSF approve a "finding of no significant impact" from the proposed construction and operation of the AMANDA project at the Amundsen-Scott South Pole Station. Preparers of this Document Robert M. Morse -- Principal Investigator, AMANDA Project Bruce Koci -- Polar Ice Coring Office Baxter Burton -- Polar Ice Coring Office Terry Johnson -- ASA Carol Andrews -- ASA Steve Meredith -- ASA Contributions Mac McCatherin, ASA; John Gress, ASA; Joe Rottman, CARA; and Chris Shepherd, ASA References 1. NSF/OPP Environmental Action Memorandum, Oct 26, 1992, regarding South Pole CARA building. 2. NSF/OPP Environmental Action Memorandum, Oct 22, 1992, "Replacement of Emergency Fuel Cache at South Pole Station". 3. Private communications, Janet Phillips, Engineer, ASA, June 1993. 4. NSF/OPP Continental Systems Regional Oil Spill Contingency Plan, Jamestown Marine Services, Inc., Dec 14, 1992 5. Bruce Koci, PICO, ``The AMANDA Project, Drilling Precise, Large Diameter Holes", April 1993. 6. Private communications, Prof. Charles Bentley, University of Wisconsin, 1993. Figure Captions 1. South Pole Science Construction Schedule. Schedule for the period Jan 93 to Jan 97. 2. South Pole Site Plan. Plan gives the relationship of the new AMANDA/CARA building at the Astrophysics Site to the present South Pole Station. AMANDA is located approximately 1 km grid NNW of the Dome. 3. An Enlarged Presentation of the AMANDA/CARA Site. Shown is the 1 + 9 AMANDA borehole configuration, with the central hole about 25 ft. grid West of the AMANDA building. Also shown about 300 ft. grid WEST of the AMANDA building is the area in which PICO will set up its drilling equipment. The Jamesway shown is a temporary structure to house the AMANDA project until it can occupy the building on January 10, 1993. 4. PICO's hot-water drilling layout. Site plan shows the locations of the cable and hose winches, the down-hole sheave complex, and the pumps, heaters, and hot water storage facilities. 5. PICO's hot-water drilling layout-elevation view. View shows position of down-hole pumps, water reservoir, and cable sheaves.