Fluor Hanford ALARA Center Activity Report, Aug 27, 2007 (TPD0708011)

1. Washington Closure Hanford subcontractors visited the ALARA Center seeking advice for tar removal from the surface of 116-C tank in preparation for demolition. We suggested they contact United Western Supply, which specialize in surface preparation. United Western Supply phone number is (888) 873-1066. You can also internet search “surface preparation” to find companies that specialized in that type of work in your location.

1. DOE Office of River Protection, TF Engineering, visited the ALARA Center to gather information about gamma cameras. The focus of the visit was to determine if a gamma camera could assist in mapping and clean up of the waste spill at S-102. For further information on gamma cameras, including an evaluation by Argonne National Laboratory on how gamma cameras assist D&D activities go to www.edocorp.com/NuclearDetectionImages.htm.

1. The ALARA Center continues to provide support for glove bag training as part of the RCT continuing training program. The course includes classroom training and “hands-on” practical exercises for students to practice working with and inspecting glove bags.

1. A CH2MHill Radiological Engineer contacted the ALARA Center to request information about how to obtain a gamma camera in support of clean up and recovery of the Tank Farm S-102 spill. We also provided “Guidelines for Decontaminating a Spill” (attachment 2) with the other requested information. S-102 spill recovery planning is ongoing.

1. The ALARA Center provided three new glovebags to WCH for anomaly processing. T-Plant originally ordered the glovebags but could no longer use them. The Center still has about 12 4 ft X 4 ft glovebags still available. Contact the ALARA Center if you would like some of these glovebags.

Shielding Materials

Most radiation fields at Hanford are combinations of different kinds of radiation. Normally, temporary shielding is installed to reduce dose rates from fast neutrons, thermal neutrons, beta, and gamma radiation.

Fast neutrons are attenuated by materials containing large amounts of hydrogen. The interaction of the fast neutrons with hydrogen slows the neutron to thermal energies where they are more easily attenuated. Dense metals, such as lead, will also slow fast neutrons by inelastic scattering at higher energy levels. Shielding materials commonly used are water and polyethylene.

Thermal neutrons are slowed by water/polyethylene and can be virtually eliminated by the presence of high thermal neutron cross-section materials such as boron, lithium, or cadmium.

Beta radiation is best shielded using materials with few protons and neutrons in the nuclei so that bremsstrahlung, a secondary radiation similar to gamma, is not created. Plastics, rubber, concrete, and light metals like aluminum make good beta shielding. Rule-of-Thumb: Range of beta particles in air is ~12 feet/Mev of energy.

Percentage of 1 Mev Beta Radiation Shielded by Various Common Materials/Equipment

Attachment 2

DOE Lessons Learned (www.eh.doe.gov/ll) was forwarded to you by the ALARA Center. If you have questions about Lessons Learned, please visit the DOE Lessons Learned website.

Title: YELLOW – Don’t Let Your Guard Down When Preparing Facilities for Decommissioning and Decontamination

Lesson ID: 2007-CH-BNL-ERP-001 (Source: User Submitted)

Originator: Brookhaven National Laboratory Environmental Restoration Projects

Date: 6/4/2007 Contact: Dean Atchison, (631) 344-7854, atchison@bnl.gov

Classifier: N/A Reviewer: Edward A. Sierra

Statement: – When reducing system operations and building occupancy while preparing facilities for decommissioning and decontamination (D&D), a formal assessment of the need for active systems and their operation should be performed to eliminate unnecessary systems as soon as practical. Prompt de-activation of systems that are no longer needed will reduce the risks from system component failure and minimize surveillance and maintenance needs.

–  System operations manuals/procedures should be revised and reissued to reflect the modified functionality of systems remaining in operation to support D&D of a facility. This includes the need for routine system surveillance and functionality checks of alarm annunciation panels.

–  Facilities that are being deactivated in preparation for D&D are vulnerable to a loss of continuity in required routine inspections and maintenance. This may occur due to the departure of key personnel previously responsible for implementing surveillance and maintenance or the result of inadequate planning.

–  When deactivating facilities in preparation for D&D there is the potential for adverse “system” effects when components are operating in a state of disrepair. Allowing a system to operate with a component in a state of disrepair (e.g. cooling tower cooling fins) can lead to the failure of a significant component (e.g. pump seal failure from tower debris) within the system.

Discussion: On September 19, 2006, Brookhaven National Laboratory’s (BNL) permanently shutdown High Flux Beam Reactor (HFBR) experienced extensive flooding within the reactor building due to mechanical failure of an air conditioning unit cooling water pump seal. Approximately 26,000 gallons of water originating from the BNL domestic water system was spilled into the equipment level of the reactor building. Although the source of the spilled water contained no hazardous or radioactive contaminants, analyses of samples removed from the accumulated spilled water within the HFBR indicated elevated tritium concentrations. The clean air conditioning water that was released in the building absorbed residual tritium from within the HFBR. As a result, all 26,000 gallons of spilled water was handled and processed as liquid radioactive waste.

Analysis: A team was commissioned to conduct an independent investigation and causal analysis of this event using the “Barrier Analysis” technique. The causal analysis resulted in the identification of the following list of root causes:

–  Supervisory alarms “disabled” eliminating remote alarm function

–  HFBR D&D status resulted in reduced maintenance of alarm panel

–  HFBR D&D status resulted in reduced maintenance of air conditioning cooling towers

–  Inadequate management control for the reductions in Surveillance and Maintenance (S&M) of the remaining systems while preparing the HFBR for near and long-term D&D

Actions: The following recommendations were proposed to prevent recurrence of this event:

–  Perform an analysis of the remaining active systems within the HFBR and determine its need and necessity throughout the remainder of the near and long-term D&D activities. Based on the results of the analysis, remove unnecessary systems from service and modify remaining systems to meet the current needs.

–  Install a leak detection system in vicinity of remaining liquid systems within the HFBR.

–  Revise the HFBR S&M manual to reflect routine scheduled maintenance necessary to ensure the HFBR is maintained in a safe, reliable and compliant condition.

Savings: Avoidance of leaking water into a radiologically controlled area saves approximately $15/gallon in remediation cost.

Keywords: DECOMMISSIONING AND DECONTAMINATION,

Attachment 3

Attachment 4

Guidelines for Decontaminating a Spill Area that Can’t be Released within a Few Days

Sometimes radioactive material is spread when a spill occurs. If the spill is in a small area, it can usually be cleaned up quickly and the area released from radiological controls. Some spills are much larger and occur on complex surfaces that contain crevices or surfaces that absorb the contamination, i.e., soil. The following guidelines may be useful in establishing a disciplined process to contain the spill and then attack the cleanup and release of the spill area.

1. Ensure the spill has stopped and actions have been taken to keep the spill from spreading. This may require covering the spill area with a tarp, painting all surfaces with a strippable decon paint, spreading absorbent in the spill area, or some other technique.
2. Take surveys, especially air samples in the downwind direction if the spill is outside a radiological work facility. Establish a perimeter around the spill and post with Radcon Warning Signs.
3. Assign someone to be in charge of the decontamination effort. That person needs to immediately determine how many resources are available and obtain a charge code to pay for the cleanup. If the spill is in a radiation area, a current radiation survey should be taken and a dose estimate prepared. Establish a “command center” near the spill area and prepare detailed maps that can be used to show what areas are being controlled and the current contamination levels.
4. If the spill occurred on the ground or inside a building it is desirable to layout gridlines to track contamination levels and document which areas have been decontaminated. Record these lines on the maps at the command center and on the Radcon Survey Forms.
5. Identify these gridlines with letters and numbers so that each grid square can be tracked. For Example: If letters are assigned to each vertical line and numbers to each horizontal line the upper left corner of each grid square will have a unique identifying number. The gridlines can usually be marked with tape, rope, stakes or landmarks.
6. Determine whether the spill has to be cleaned up, can be covered and posted as a Fixed Contamination Area, or can be contained until D&D activities begin later. Decide “How Clean is Clean”. Note this decision may change after several attempts to decontaminate the area have failed. Other factors that affect this decision include whether the area was contaminated before the spill occurred, radiation levels in the spill area, weather conditions (if outside) and available resources.
7. Determine the best strategy to accomplish the decontamination. Normally, spills are cleaned from the lowest levels and work towards the higher levels. If you don’t have a detailed survey of the work area you will have to base your strategy on what you know. You may decide to wipe down the entire area before attacking each individual grid square. Look for patterns of contamination spread from the source. If the spill occurred outside, assess what’s in the spill area. In the past, spill areas have included vehicles, buildings, tools, equipment and materials. If inclement weather is a factor, concentrate initial efforts on keeping the contamination from spreading. If the wind is blowing, set up a windbreak and clean from the upwind side in the downwind direction.
8. If the spill occurred in a radiological work facility the floor tiles may be made from asbestos. Sometimes the floors have more than one layer of tiles and the lower layers may be asbestos. Asbestos removal will complicate the cleanup. You may want to consider wiping up the accessible contamination and paint the floor to fix the contamination remaining in crevices. Then post it as a “Fixed Contamination Area” and leave the tile removal to a D&D contractor.
9. Hold a planning conference to organize the different groups and coordinate the decontamination efforts. If technical work documents are required, have them prepared and approved. Determine what is to be done with the waste. Stage the required protective clothing and materials.
10. When all preparations are complete, hold a pre-job briefing and layout the plan and what is to be done that shift. Hold a Plan-of-the-Day meeting each day to provide status and identify what assistance is needed from support organizations. Document the results of the POD so Managers do not have to keep giving verbal status to everyone. Distribute the POD to key managers that have a “need-to-know”.
11. Begin the decontamination and take surveys as you go. Release grid squares as you go and when appropriate, move the perimeter posting in to reduce the size of the spill area. If the decontamination is going to take several days, recommend a dedicated team of personnel be assigned so there is consistency and no question about where surveys were taken. If dose rates are high enough to require rotation of personnel to lower their dose, try and keep lead personnel to maintain consistency.
12. Interview workers and RCTs performing the work to obtain recommendations on improvements. Modify the plans, as necessary. Start each shift with a pre-job briefing and emphasize what has been accomplished, what problems exist, and what actions are required.
13. Take enough surveys in each grid square to be representative of what’s there. These surveys may include smears, large area wipes and samples of paint, concrete, soil, etc. When you’re satisfied that the grid square has been decontaminated and you have the surveys to prove it, recommend inviting another person not involved in the project to review the surveys and concur that each grid square has been decontaminated and can be released.
14. At the control center, update the detailed maps to show the status of the decontamination. Each time a grid square is released, mark it off.
15. Continue to move the perimeter in as the size of the controlled area shrinks. Once the entire area is released from radiological controls hold a debriefing to document lessons learned. Assign actions with due dates as appropriate. Follow-up later to ensure all actions were completed.
16. Prepare a package of the survey data, reports, and photos for historical purposes.