Optimizing Radiochemistry Lab Performance in Decommissioning David - - PowerPoint PPT Presentation
Optimizing Radiochemistry Lab Performance in Decommissioning David A. Montt, CHP Sherman the resident bald eagle at Yankee Rowe Associate & Senior Health Physicist Dade Moeller and Associates, Inc. 1 Acton Place, Suite 201 Acton,
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Optimizing Radiochemistry Lab Performance in Decommissioning
David A. Montt, CHP Sherman the resident bald eagle at Yankee Rowe Associate & Senior Health Physicist Dade Moeller and Associates, Inc. 1 Acton Place, Suite 201 Acton, Massachusetts 01720
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Optimizing Radiochemistry Lab Performance in Decommissioning
YNPS History
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Optimizing Radiochemistry Lab Performance in Decommissioning
demolition progression from March 2003 to December 2003
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Optimizing Radiochemistry Lab Performance in Decommissioning
critical necessity.
in a construction environment in a rapidly changing environment
be performed on site recognizing resource constraints (personnel, utilities and budget)
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Optimizing Radiochemistry Lab Performance in Decommissioning
Needs
– Operating
nature.
– Ion Analysis (Dionex analyzer, or equivalent) – Graphite Furnace (metals) – Atomic Absorption (metals) – Total Organic Compounds (TOC) – Gross Beta – Gamma spectroscopy optimized for operating plant radionuclide levels (plant
– Tritium, C-14, low energy beta analyses using liquid scintillation technology – Boron analyses by titration or automated instrument analyses – Sediment, – pH, – conductivity, – Oil and Grease
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Optimizing Radiochemistry Lab Performance in Decommissioning – Decommissioning
site
turnaround time becomes the driver.
– Gamma spectroscopy optimized for operating plant radionuclide levels (focused environmental levels) – Tritium, C-14, low energy beta analyses using liquid scintillation technology – Sediment, – pH, – Conductivity – Oil & Grease
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– Final Status Survey (FSS)
– Groundwater Monitoring
workload unexpectedly
radiological environmental
– Unusual, one-of-a-kind operations (examples at end) – Effluents
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Need to make Sure Radiochemistry is effectively integrated into all Scheduling.
– FSS – Groundwater Group – Effluents Program – Remediation Group (sample analysis) – Non Radiological
– Unique Problem Solving Campaign Leaders – Construction personnel/contractors with little to no radiological background – Regulators – Other stakeholders (public)
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Optimizing Radiochemistry Lab Performance in Decommissioning
– Value of time savings for on site analyses
Regulators
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Optimizing Radiochemistry Lab Performance in Decommissioning
– Gamma Spectroscopy – Liquid Scintillation counting
possibly others
– Oil and Grease – pH, Sediment – Particle size analysis (0.5u, 1.0u, and up filters) – Boron titration (early on if primary water tank leaks during plant history – Look at on case by case basis; know your plant history
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Optimizing Radiochemistry Lab Performance in Decommissioning
– Want NIST Traceable calibration sources
– 4 liter M water, 4 Liter M soil, I liter M water, 1 liter M soil, LSC vial, Planchets w/filters and soil – Non Rad: 100 ml jar soil, 100 ml jar water/gel, 20 ml bottle PCB swipes, etc.
– Environmental levels for Gamma Spectroscopy – Environmental levels for LSC (H3, C14, etc.)
– May want NIST traceable check sources
– Anticipate unusual Regulator special requests (total uranium, e.g.)
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smaller temporary facility
(electricity, water, temp control, waste)
and plan in advance
it.
performance – take control early on before problems arise – have solution implemented.
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incorporate early on.
attending daily and special meetings
– integrate with Non-Rad Environmental early on, – update programs early on to ensure these are in place and work – long lead time especially with FSAR, QAPP, RECP, NPDES, TSCA – Liquid Effluents can be challenging if not addressed effectively early on – understand what you need & want to do. – Remediation Group will be closely tied to, or part of, HP – establish link early on in programs and people
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Optimizing Radiochemistry Lab Performance in Decommissioning
EXAMPLE
– Initially, following movement of Chemistry Lab to a Trailer to support of the Primary Auxiliary Building (PAB) demolition, three HpGe’s were installed leaving a footprint for a 4th. – Based on counting times necessary to meet DCGL’s (30 min/sample) and implementation of MARLAP protocols, a though put of 100 samples per day could be processed – Understanding the necessity to dry samples, the existing methodology created a bottleneck.
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Optimizing Radiochemistry Lab Performance in Decommissioning
– No one owned the Sample prep trailer at that point, so Chemistry took ownership realizing it needed to maintain full control to optimize sample throughput and control prioritization requirements of stakeholders. – 2 drying ovens capable of drying in open pans limited sample production to 70 samples in 24 hours. 2 additional
the older ovens. – A method tried at Maine Yankee was tested and implemented at Yankee Atomic. – Samples were dried in plastic Marinellis in the ovens with the covers off at 130 degrees C. The melting limit was 150
well, permitting up to 112 samples to be prepped in a 24 hour period and meshed well with lab production capacity.
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collection, prep & drying)
– Moved sifting of samples to the field
rock in trailer
and signed results.
– Permitted use of closed loop sample hood – Enhanced housekeeping of Sample Prep Trailer – Greatly minimized potential for cross contamination of samples
basis (next page)
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Optimizing Radiochemistry Lab Performance in Decommissioning
– Eliminating at least 2 handling steps, – 2 potential cross contamination opportunities – The need to weigh each Marinelli and cover (the weights between batches did not vary by more than 1%) – The opportunity to introduce bar code scanning of samples for COC simplification through analysis – Elimination of large volumes of soil in the prep facility as the samples were sifted in the field for > 90% of the samples – Chemists who understood lab operations and prep
– Electric Sifter Carts were designed and successfully field tested, but never gained popularity. – In both the lab and prep facility, the move to self contained ductless hoods was implemented, greatly improving
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Optimizing Radiochemistry Lab Performance in Decommissioning
– Did not mandate percentage of moisture to dry samples to, only that it be minimized – Guidance would lead you to believe must be no more than a small fraction of 1% – Indicated need to individually weigh each sample container and cover – Recommended removal of all extraneous material from sample > 3/4” in dimension except
– With +25% agreement between split samples at DCGL level (e.g.), 1% error seemed overkill. – Evaluate and develop technical basis document.
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Optimizing Radiochemistry Lab Performance in Decommissioning
– Electrical supply (current and voltage) fluctuations were not uncommon. – Impacted some of the more sensitive instrumentation – e.g., LSC – Vibration of large trucks moving on road had similar impact
– Value to counting no more than 20 samples per run with NIST source, blank, followed by spike and blank at end.
– Maintained 2 sigma criteria historically used on site, but flagged data at 3 sigma for further investigation. – Co-located FSS air and water samples with historical environmental sample locations to permit scaling to historical data collected over 30+ years for trend analysis.
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Optimizing Radiochemistry Lab Performance in Decommissioning
– Anticipate your customers early on – Anticipate the analyses plant will most likely need and that provide the greatest benefit – Campaign early on, get buy in and get to work – Set goal of never being the bottle neck in any effort Chemistry/Radiochemistry will be supporting – Figure out what you need to achieve goal – Get Upper management buy in – Get to work – Make sure you have the right team in place – Need good mix of regimented regulars and non-regimented problem solvers – Communication internal to the group and external to the group are critical. (seems obvious but practiced sparingly – not a commodity to be rationed) – There is no avoiding the marriage of non-radiological and radiological effluents in decommissioning.. – Groundwater will most likely be the first opportunity for this. – Hydrogeology will be a good second major for RETS/REMP engineers and scientists…. – As will Non Radiological Environmental Science
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(of Main Presentation – examples of Unique, One of a Kind Evolutions Typical of Decommissioning Follow for Future Reference)
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Optimizing Radiochemistry Lab Performance in Decommissioning
Operations
– PCB Thermal Desorption – Using Thermal Desorption to Remove Tritium from Concrete – Developing a Flexible Effluents Program to Permit Rapid Adaption to Changing Conditions – Spent Fuel Pool Drain Down & Direct Discharge – Extensive Use of Bench Testing – Effective Integration of Non Radiological Environmental Program in to Radiological
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Chemistry Opportunities in Decommissioning
– History
made with PCB oil to maximize its ability to move with the steel as it expanded and contracted with temperature changes
+105 ‘F during 30+ years, the paint matrix started to physically degrade, releasing PCB oil, and PCB paint chips to the environment under the VC, in storm drains and in Sherman Pond sediment.
painting over the contaminated paint on the Ball to contain the source.
was looking at having to ship about 25% of the surface soil in the industrial area off site.
tripled (increased by 300%).
– Remediation Method Chosen
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Optimizing Radiochemistry Lab Performance in Decommissioning
– Processing Rate was Impressive – The Unit took soil feed in batches – Samples were taken at predetermined rates (1 sample per cubic yards) at feed and processed soil ends. – Remediated soil was consistently < 1.0 ppm PCB – Soil was run through the system by auger, heated to 725 degrees, volatizing the PCB, which was subsequently condensed and captured in a vessel for recovery/disposal.
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Optimizing Radiochemistry Lab Performance in Decommissioning
– Driving of PCBs also drove off moisture content – Soil was also contaminated with licensed material gamma emitters (Co 60, Cs 137, Ag 108m, etc.) and Tritium – The unit temperature was too low to be concerned with metal volatilization, but moisture was driven off, captured by condensation, and re-used to re-hydrate the soil.
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Optimizing Radiochemistry Lab Performance in Decommissioning
– The Oven/Auger discharge contained a bag house to capture soil – The raw condensate was captured, the PCB oil separated from the water, the water was then channeled to a particulate then charcoal filter – Any radioactive effluents present would also show up in the raw condensate – This is what was sampled, vs. using a stack monitor, to check for effluents.
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Optimizing Radiochemistry Lab Performance in Decommissioning
– On a few occasions early in the process, tritium was identified at ~1800 pCi/L. – Tritium levels dropped in the following three samples collected every 2 days. – Levels were then non-detect though the rest of the operation which continued for ~ 9 months. – Water was never discharged, as it was continually re-used to hydrate the soil. In fact water had to be added to the system. – The company who owned the technology had a Massachusetts permit allowing them to discharge up to 0.5 ppm PCB in water. – Yankee’s limit for PCB in water discharges was non-detect.
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Optimizing Radiochemistry Lab Performance in Decommissioning
– During system set up, assembly and operational testing, dust could occasionally be observed leaving the stack, or the tower where the dry soil was he hydrated. – As a result of this, an air sampler was placed in the vicinity of the unit where predominant wind direction moved the dust. – No licensed material was detected on the particulate filters.
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presented some interesting challenges in meeting DCGL’s for concrete mandated by Massachusetts.
– Extensive core sampling of RSS indicated minor levels of tritium and no C14. – Later and more extensive core sampling found higher levels of tritium, challenging the original plan to use significant tonnage of the RSS concrete (containing minimal levels of activation products), as back fill. – Levels as high as 500 pCi/g, averaging 120 pCi/g – State of MA mandated 12 pCi/g – Based on the tritium levels, most of the RSS concrete would not be available for use as fill.
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Optimizing Radiochemistry Lab Performance in Decommissioning
– Someone suggested using the PCB Thermal desorption unit to process the concrete to drive the excess moisture and tritium as tritiated water from the concrete. – If concrete levels could be reduced to 10 pCi/g or less, concrete would be processed using this methodology – The concrete was typically 1” in average dimensions. It could be processed, at a slight additional cost, to 3/4” dimensions. – Chemistry was asked to evaluate this on a Thursday morning, and to provide results and conclusions by the following Monday morning, as contract was under negotiation for PCB remediation with vendor and decision on Tritium remediation had to be made that Monday.
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Optimizing Radiochemistry Lab Performance in Decommissioning
– Vendor lab was contacted. – Oven was available at 300 degrees C (~572 degrees F). 2 hour retention time would be simulated. – Procedure and instructions were drafted up and emailed to the lab. – A courier deliver the RSS concrete samples that afternoon. – Test was conducted Friday and Saturday in vendor lab. Results from vendor lab were emailed out Saturday afternoon to Chemistry.
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Optimizing Radiochemistry Lab Performance in Decommissioning
– Chemistry evaluated results, and drafted a report for Monday Morning – Average tritium remaining was just over 10%. – Question on cost effectiveness of pulverizing to 1/4” dimension was raised. – Levels of 5-6% of original tritium concentration would have resulted in a go ahead. – Decision was made to not utilize this process. – Results of study follow. – RSS concrete was shipped to Utah for burial.
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Rapidly Changing Environment
– Plant liquid wastes still had to be dispensed with. – In plant treatment would not be available for the duration of D&D – Trenches and open foundations were anticipated to fill with water and contain radioactivity – PCBs & RCRA 8 metals were also anticipated – Continuous discharges and batch discharges were expected – pH, sediment were also as potential problems in regards to discharging to Sherman Pond
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– NPDES permit up for renewal and to include specifics for SFP discharge – Added construction dewatering category – Specified plant and portable skid treatment – EPA & MADEP approach was to focus on quality of water discharged, and pathways with contingencies to use alternate discharge pathways as D&D progressed.
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Optimizing Radiochemistry Lab Performance in Decommissioning
– ODCM concentrated on in plant systems, and was revised to include portable, temporary skids – Provision was added for continuous and batch discharges from trenches and foundations. – Added sampling using composite samplers and/or grab samples. – Contingencies for loss of composite samplers included hourly grab samples – Continuous sampling included three initial grab samples – if all three results were within a certain level of agreement, continuous discharge with hourly grabs was permitted.
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Optimizing Radiochemistry Lab Performance in Decommissioning
– For the most part, pH and sediment precluded direct discharge and required the use of temporary processing systems employing Baker Tanks – Radiological constituents were not limiting – Concrete dust and rubble were the source of pH and sediments challenges, and it was ubiquitous. – PCBs also mandated treatment in Baker Tank Systems. 0.5 micron particulate filters were the most effective tool for abating PCB Levels in water – RCRA 8 Metals were not limiting at discharging water with low levels was permissible, and was based on 57 cfs discharge rate from Sherman Dam. If this discharge rate was higher, metal levels could be higher in the effluent, but this flexibility was never necessary.
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Optimizing Radiochemistry Lab Performance in Decommissioning
– Demolition contractor rented and operated the water processing systems (basis for this) – YAEC provided analytical support, approved discharges,
– Outfalls 003 and 004 were primaries for temporary system discharge points – Processing tanks utilized 120 mesh pre-filter on tank 1, settling tank with recirculation capabilities in tank 2, with the capability for pH adjustment, followed by 1 micron, or 0.5 micron filtration (controlled PCBs and fine sediment) – Fine sediment affected color of the water, was a NPDES permit requirement, and required considerable reprocessing near the end of the project.
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Container During Demolition
– Presented challenges – As steel shell was removed, rain could enter the VC, flush out radionuclides and contaminate the concrete and ground below, increasing the level
– In addition, the paint used to contain the older PCB laden paint, had to be stripped for cut lines to prevent formation of dioxins. – This introduced the potential for PCB contamination in the water, and expansion of affected site areas.
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Optimizing Radiochemistry Lab Performance in Decommissioning
– SOLUTION – The solution was a bermed area covered with an impervious barrier to contain the water under the VC – This water was processed through a temporary system located adjacent to the VC (wet side) and positioned to take advantage of gravity flow between tank 1 and tank 2. – Water capacity of the tanks was limiting at times as an EPA certified methodology was required for PCB analysis and RCRA 8 metals analysis and took one week from shipment of samples to receipt of results. – Heavy rains frequently challenged processing capability. – Drops of steel occasionally penetrated the barrier mandating repairs – In one very heavy storm, the berm failed and overflowed, resulting in an estimated loss of ~5000 gallons. ~3000 gallons were captured and pumped back into the berm after the berm was repaired. – Initially water in the berm had levels of PCBs at 2 ppm, and detectable cobalt and cesium. These dropped off as time progressed.
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– Bench Testing was an invaluable tool during Decommissioning
discharge
remediation using thermal desorption equipment
and determine potential for wide swings and at which points when adjusting large volumes for discharge
scope were discovered but not communicated. Screen Well house intake pipe plugging methodology was a good example.
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Optimizing Radiochemistry Lab Performance in Decommissioning
– Initially the plan was to plug the discharge line, pump out the water using direct discharge, and fill the pipe with concrete – For reasons still unclear (cost? schedule?), the decision was made to pump the concrete slurry directly into the SWH after the plug was placed by divers without pumping the water out first. – At the request of a conscientious project manager, Chemistry investigated the impact of this change in strategy. – The concrete vendor was contacted and a sample of the mix was
– 2 gallons of water from the SWH were collected – The concrete was mixed and added to the SWH sample water in proportions based on the volume of water in the SWH and the volume of concrete to be added. – pH was monitored and recorded frequently until readings stabilized. – Initial readings climbed to 12.8 pH units, and stabilized to 12.2 – 12.3 standard units within the first hour. TSS levels, sampled every 15 minutes were high initially, but never exceeded the NPDES limits.
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– A report on the study was penned and widely distributed with recommendations from both Chemistry and the water processing lead. – It was recommended several Baker tanks be leased to permit processing of the water expeditiously, and to provide additional water processing capacity in the future for the increasing number of open pits and open foundations that were challenging the existing system. – The recommendation was not well received initially due to the costs and perceived schedule impacts. However, bench test results left little doubt of impact should recommendations not be implemented. – Following intense negotiations with the demolition contractor, 4 additional baker tanks with processing and recirculation capabilities were placed in service, and except on rare
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