2008 RETS-REMP Workshop, June 23-25, 2008, Charlotte, NC, Sponsored by Duke
Energy
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2005 NUMUG Meeting
Integrating a Doppler Sodar with Nuclear Power Plant Meteorological Data
Thomas E. Bellinger, CCM ABSTRACTOn November 13, 2002, a large grass fire occurred near the Dresden Nuclear Power Station. This fire created a large plume of smoke that was visible on the Chicago NWS Doppler radar and was documented with numerous photographs. The photographs of the plume show an interesting vertical structure that could not be discerned from the onsite Dresden Nuclear Power Station meteorological tower data. The nearby IEMA Doppler sodar provided vertical measurements that explained the vertical structure of the plume quite well. Integrating the IEMA Doppler sodar with the meteorological measurements from Braidwood, Dresden, and LaSalle nuclear power stations ultimately can provide emergency responders with a valuable picture of how and where accidental releases may be transported from these sites.
Real-time Plume
Depiction of Potential Nuclear Power Plants Releases
Thomas E. Bellinger, CCM ABSTRACTA computer program was developed for automatically displaying where potential releases might travel from any of the Illinois nuclear power plants. Released “puffs” move with the onsite meteorology and grow with stability class. Elevated, ground level, and mid-level releases are depicted and developed using the data from the various levels of each meteorological tower. Nearby surface reports that are FTPed from the Internet every 20 minutes are plotted over the display along with a bilaterally interpolated grid from these observations. The program was designed to keep track of where a plume is especially when conditions get complex with wind shifts, fronts, speed changes, etc. Regional and site-specific displays gave been developed and also show local evacuation subareas. I have seen all kinds of meteorological conditions like near calms, strong winds, frontal passages, Lake Michigan influenced flow, as well as my personal favorite, boundary layer decoupling. It has been a useful tool in showing the fundamentals of dispersion and what really can happen in the atmosphere. Attached below are some sample outputs from this program.
Practical User Tips for ARCON96
Author: Y. J. Lin ABSTRACT The ARCON96 dispersion model issued by the NRC in May 1997 is a revised version of ARCON95. This software has been widely used to assess design basis dispersion factors (X/Qs) at the control room or technical support center air intakes following an accidental release under the influence of building wakes induced by the reactor block. A user’s guide was published as NUREG/CR-6331, Rev. 1. The model is relatively easy to use, but there are several assumptions and approaches that users need to consider in order to obtain the proper results. In March 2000, a panel discussion for control room habitability analyses was conducted at the NRC headquarters. In that panel, the main topics concentrated on were the methodologies and approaches used for the ARCON96 model. Recommendations were also made for possible improvements to be implemented for the future revision. Subsequently, NRC issued Regulatory Guide 1.194 in 2003 to present the regulatory positions regarding the approaches to be implemented in using the ARCON96 model. Several approaches adopted by the ARCON96 code, but were not implicitly addressed in the User’s Guide, could affect the accuracy of the modeling results. The main purpose of this paper is to discuss essential issues that are not addressed either in ARCON96 User’s Guide or in RG 1.194, but have the potential to affect the results. The paper will also address improvements and suggestions that could be added upon to enhance the model performance.
The Role of Meteorology in the Nuclear Power Industry
Theodore A. Messier ABSTRACTThe science of meteorology plays several roles in the nuclear power industry. Meteorological measurements are used as input for decisions on site acceptability (design basis accident analyses), plant construction, plant procedures, emergency response, and continued operation (ODCM dose projections) of the plant. The Nuclear Regulatory Commission has provided guidance on the collection, reduction, and application of meteorological data. A summary of this guidance, as well as other appropriate information, is presented. The NRC focus on risk-informed and performance-based regulation, coupled with the deregulation of the electric generating industry, has lead to reductions in staff and discretionary spending in our industry. Resources are expended in the areas that directly affect electricity generation, and other areas may not receive as much attention as they have in the past. Framatome ANP, responding to current issues in our industry, has developed a software application to aid non-meteorologists in maintaining high quality meteorological data. This application allows for data storage, data checking, data editing, and the determination of annual data summaries and atmospheric dispersion factors. Further discussion is provided on this software application and how it can help the non-meteorologist in charge of the plant’s meteorological monitoring system.
The Graniteville Train Crash: Emergency Response Support provided by the Savannah River National Laboratory
Matthew J. Parker, CCM ABSTRACT During the early morning hours of January 6, 2005, a train crash in Graniteville, South Carolina, resulted in the airborne release of several toxic chemicals, including chlorine, and nine deaths and the hospitalization of 100s of others. The Atmospheric Technologies Group of the Savannah River National Laboratory (SRNL) provided plume modeling and weather forecast support to the myriad of emergency responders at the scene through a pre-existing mutual aid agreement with regional county emergency management agencies. The approach, including prior training, to simulating the chlorine release and a discussion of the prevailing weather conditions will be presented. A post-analysis of the release will also be given based on non-meteorological data, such as local terrain influences, damages to foliage and fatalities, collected during and after the event.
Temporal Comparison of Atmospheric Stability Classification Methods
Ken Sejkora ABSTRACT The Nuclear Regulatory Commission recognizes two methods for the classification of atmospheric stability to support dose calculations from routine and emergency releases of airborne radioactivity. Many nuclear facilities measure temperature differences between two or more vertical levels of a tower, and use the vertical temperature difference (delta-T) as the primary means to determine atmospheric stability. Another acceptable method for determining stability class is based on the standard deviation of wind direction fluctuations (sigma theta). Both of these methods are listed as acceptable methods in Regulatory Guide 1.21 and Safety Guide 23.
This presentation describes an evaluation of the temporal comparability of the stability classes derived from simultaneous multiple delta-T and sigma theta measurements made through time. As a result of these comparisons, it was determined that there is only limited correlation between atmospheric stability classifications obtained from two sources situated on the same meteorological tower. This relative disagreement between methods presents special challenges for determining which indication is most appropriate to use for dose assessment efforts.
Strategies for the Selection of Substitute Meteorological Data
Ken Sejkora ABSTRACTThe Nuclear Regulatory Commission provides guidance for the collection of meteorological data to support dose calculations for routine and emergency releases of airborne radioactivity. Safety Guide 23 lists wind speed, wind direction, and atmospheric stability classification as parameters important to such efforts, in support of routine effluent monitoring summarized in Regulatory Guide 1.21, and for emergency response efforts described in Regulatory Guide 1.97, NUREG-0654, and NUREG-0737.
During 2003, problems occurred with the upper level wind direction sensor on the primary meteorological tower at Pilgrim Station that resulted in the loss of this indication for an extended period of time. This loss of data would have adversely affected the 90% data recovery goal for meteorological data to support dose calculations, as specified in Safety Guide 23. In order to achieve more suitable data recoveries, upper level wind direction data from a backup tower were substituted for the missing primary tower data. This presentation describes some of the factors that were evaluated in the decision process to select substitute meteorological data.
Investigation of Meteorological Tower Siting Criteria
Ken Sejkora ABSTRACTGuidance is provided in NRC Safety Guide 23 and ANSI/ANS Standards 2.5-1984 and 3.11-2000 regarding siting criteria for meteorological towers at nuclear power plants. This guidance typically requires that towers be situated in an open field maintained in a state of natural vegetation cover. While such siting criteria are intended to minimize influences from localized conditions that could affect temperature and wind measurements, they may not be representative of conditions that occur on-site at a nuclear power plant. This presentation will discuss a comparison of two towers at one power plant, observed differences between the 10-meter measurements made at the two towers, and the potential impact of these differences in modeling the dose impact from ground-level airborne releases from the site.
Meteorological Measurement Error Analysis based on ANS-3.11-2005
Kenneth G. Wastrack ABSTRACT
ANS-3.11-2000, “Determining Meteorological Information at Nuclear Facilities,”
filled significant gaps in guidance when it was issued. However, due to
numerous advances (e.g, in-situ and remote sensing instrumentation and data
management hardware, software, and techniques), a modernization of the standard
was merited. Therefore, as ANS-3.11-2000 approached its automatic sunset data
(which required reaffirmation, revision, or withdrawal), it was decided a
revision was needed to "modernize" the standard--to be published as
ASN-3.11-2005). This paper will discuss the history of meteorological error calculation and describe the methodology in ANS-3.11-2005.
A Statistical Long-Range Atmospheric-Transport Model and Sensitivity of Modelling Results to the Input Parameters Yahui
Zhuang ABSTRACT
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