The Hazard Assessment System for Consequence Analysis (HASCAL) is being developed to support the analysis of radiological incidents anywhere in the world for the Defense Nuclear Agency (DNA). HASCAL is a component of the Hazard Prediction and Assessment Capability (HPAC), which is a comprehensive nuclear, biological, and chemical hazard effects planning and forecasting modeling system that is being developed by DNA. HASCAL computes best-guess estimates of the consequences of radiological incidents. HASCAL estimates the amount of radioactivity released, its atmospheric transport and deposition, and the resulting radiological doses

Sjoreen, A.L.

Sykes, R.I.

UNT Digital Library

HASCAL - A SYSTEM FOR ESTIMATING CONTAMINATION AND DOSES FROM INCIDENTS AT WORLDWIDE NUCLEAR FACILITIES A. L. Sjoreen Computing Applications Division Oak Ridge National Laboratory* P. 0. Box 2008 Oak Ridge, Tennessee 3783 1-6236 R. Ian Sykes TitdARAP P.O. Box 2229 Princeton, New Jersey 08543 To be presented at the ANS Fifth Topical Meeting on Emergency Preparedness and Response Aiken, South Carolina, April 1995 "The submitteu manusapt has been authored by a contractm of the US. Government under muact No. DE- AC05-84OR21400. Accmdir&. the U.S. Government retains a nonexclusive. royalty-frea liarnse to publish M reproduce the putkhed form of this an-. or allow others to do so, for U.S. Govemment purposes.- *Managed by Martin Marietta Energy Systems, Inc.,under contract DE-AC05-840R2 1400 with the U.S. Department of Energy. DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from \the best available original document. HASCAL - A SYSTEM FOR ESTIMATING CONTAMINATION AND DOSES FROM INCIDENTS AT WORLDWIDE NUCLEAR FACILITIES Andrea L. Sjoreen Oak Ridge National Laboratory P.O. Box 2008 Oak Ridge, TN 37831-6326 (615) 574-5333 SUMMARY The Hazard Assessment System for Consequence Analysis (HASCAL) is being developed to support the analysis of radiological incidents anywhere in the world for the Defense Nuclear Agency (DNA). HASCAL is a component of the Hazard Prediction and Assessment Capability (HPAC), which is a comprehensive nuclear, biological, and chemical hazard effects planning and forecasting modeling system that is being developed by DNA. HASCAL computes best-guess estimates of the consequenm of radiological incidents. HASCAL estimates the amount of radioactivity released, its atmospheric transport and deposition, and the resulting radiological doses. I. INTRODUCTION HASCAL, version 0.4, is based on the Radiological Assessment System Consequence Analysis' (RASCAL) version 2.1, which was developed for the U.S. Nuclear Regulatory Commission for the analysis of accidents at U.S. power reactors. Versions of HASCAL that run under DOS and Windows are available. At present, the major enhancements of HASCAL over RASCAL are (1) the addition of site-specific data for all power reactors in the world, (2) the addition of new source-term computation options for the new types of reactors included,and (3) the addition of the atmospheric tranqmrt model, SCIPUFF, as an alternative to the TADMOD model. Different versions of HASCAL will be developed for different computing platforms, with calculational models appropriate for that scale of machine. For example, a portable personal computer version will be available for responding to incidents in the field; a work station version will be available for more detailed analysis and emergency planning; a super computer version will be used for research applications. So far the focus has been on the R. Ian Sykes Titan/ARAP P.O. Box 2229 Princeton, NJ 08543 (609) 452-2950 personal computer version. The DOS version of HASCAL is very similar in appearance to RASCAL, 2.1. The Windows version of HASCAL has been completely rewritten so that the user interface conforms with the Windows style. 11. SITE-SPECIFIC DATA HASCAL contains a database of all nuclear power reactors in the world. This database contains the reactor name, location, type, rated power, and keys to the inventory file and files of meteorological data, if available. More detailed data are present for U.S. reactors and are being added for non-U.S. reactors. Files of meteorological data for the meteorological station nearest each reactor site are being added to HASCAL. These files contain 15-day mean hourly meteorology and standard variations for wind speeds. They can be read by HASCAL to provide default meteorologic conditions over the assessment period for the day and time of the incident for either the SCIPUFF or TADMOD models. This meteorological data file is required to run SCIPUFF in its probabilistic mode. The reactor inventory files that are being added to HASCAL contain more detailed reactor inventories than are used in RASCAL. Currently, fdes are available for PWRs and RBMKs. These inventories were computed calculations for reactors for which no accident scenarios have been defined, using the percentage of total inventory source-term option. Using ORIGEN2' and ~811 be used to perf01111 SOUW-~IIII III. SOURCE-TERM CALCULATIONS The five source-term options from RASCAL are available in HASCAL: isotopic, gross mix, plant conditions, monitor reading, and spent fuel pool. However, since several of these are specific to U.S. power reactors, two new source-term calculation options Sjoreen - 1 have been added to HASCAL: (1) a percentage of total inventory by MELCOR3 element category and (2) a prompt critical release @ a d  on the Chernobyl accident) for RBMKs. In addition, the gross mix source-term option has been modified to use the MELCOR element categories instead of the old WASH 1400 categories, and the computed source-term table is now subdivided by MELCOR element category. The new source-term calculation for a prompt critical accident involved one-third, two-thirds, or all of the core at operating power. The release fractions used are based on assessments of the Chemobyl a~cident.”~ Comparisons of the doses computed using RASCAL, PWR inventory vs the new inventory result in small differences, at most a factor of 2 to 3. The inclusion of short-lived radionuclides in these inventories will allow estimation of doses for very short exposures for those radionuclides for which dose factors are available. IV. ATMOSPHERIC TRANSPORT CALCULATIONS The inclusion of SCIPUFF in HASCAL provides the capability of probabilistic prediction of atmospheric transport. The multidimensional wind field capability allows SCIPUFF to treat longer range assessments than can TADMOD. However, wind field data are not yet available in HASCAL. SCXPUFF does not currently include building wake, while TADMOD does. The dispersion algorithm in SCIPUFF is based on second- order closure theory and is therefore very different from that in TADMOD. Also, the DOS version of SCIPUFF does not include the effects of rainfall. Differences in resulting concentration predictions from the two models can be more than an order of magnitude under extreme conditions when the atmosphere is very stable or for very light wind conditions. SCIPUFF provides a probabilistic prediction of the atmospheric dispersion and surface deposition processes, with the capability to model multidimensional, time- dependent wind fields. Uncertainty in the wind field, including both boundary-layer scale turbulent eddies and larger scale unknown variations, leads to a random component in the concentration field which requires at least the mean value and the standard deviation for a quantitative description. SCIPUFF uses turbulence closure theory to predict the concentration fluctuation variance as a function of the wind field and provides a probabilistic description of the resulting impact using a parameterized probability distribution function.’ HASCAL can then use the SCIPUFF prediction to compute probabilistic radiological doses, and provide an assessment of likelihood for various levels of h d t h  effects. A new interactive graphics interface is used to display the SCIPUFF results from HASCAL. V. DOSE CALCULATIONS The dose calculations in HASCAL are designed for comparison to U.S. EPA protective action guides.8 They are unchanged from RASCAL, except that SCIPUFF does not compute cloud shine dose. The data used for those calculations have been expanded to take into account as many radionuclides as possible from the newly calculated reactor inventories. However, only about 300 of the approximately 800 nuclides in the inventory files match with the approximately 800 nuclides in the Federal Guidance 11 and 12 reports (refs. 9 and 10, respectively). Even fewer 30-day dose factors are available. VI. PLANNED ENHANCEMENTS Planned enhancements to HASCAL include adding other types of radiological facilities, including research and production reactors, enrichment and storage facilities, waste procesSing and storage facilities, and mining and milling operations. Incident scenarios for the various types of power reactors are being developed. Additional scenarios appropriate for each type of facility will be developed, aIong with models of damage response and the resulting doses from various kinds of weapons attacks on worldwide nuclear facilities. ACKNOWLEDGEMENTS Research sponsored by U.S. Defense Nuclear Agency under an Interagency Agreement under Martin Marietta Energy Systems, Inc., contract DE-AC05-840R21400 with the U.S. Department of Energy. REFERENCES 1. A. L. Sjoreen, G. F. Athey, J. V. Ramsdell, and T. J. McKenna, RASCAL Version 2.1 User’s Guide, NUREGKR-5247 Vol. 1, Rev. 2 (ORNL-6820), U.S. Nuclear Regulatory Commission (1994). 2. A. G. Croff, A User’s Manual for  the ORIGEN2 Computer Code, ORNLlTM-7175, Oak Ridge Nationai Laboratory (1980). R. M. Summers et al., MELCOR 1.8.0: A Computer code for  Nuckar Reactor Severe Accident Source Term and Risk Assessment Analysis, NUREGKR- 5531 (SAND 90-0364), U.S. Nuclear Regulatory Commission (1991). 3. Sjoreen - 2 3. 4. 5. 6. B. Sorensen, "Chernobyl Accident: Assessing the Data, " Nucl. SaJq, Vol. 28, No.4 (1987). USSR State Committee on the Utilization of Atomic Energy, 'The Accident a the Chernobyl Nuclear Power Plant and its Consequences," Working Document for the Post-Accident Review Meeting, Informarion compiled f o r  the LQEA Experts ' Meeting, 25-29 August 1986, Vienna, Part I. & m a l  Material, draft (August 1986). R. I. Sykes, W. S. Lewellen, and S. F. Parker, " A Gaussian Plume Model of Atmospheric Dispersion Based on Second-Order Closure," J. Clim. Appl. Met., 25, 322-331 (1986). R. I. Sykes, S. F. Parker, D. S. Henn, and W. S. 7. 8. 9. W. S. Lewellen and R. I. Sykes, "Analysis of Concentration Fluctuations from Lidar Observations of Atmospheric Plumes," J, Clim. &pi. Met., 25, 1145-1154 (1986). U.S. Environmental Protection Agency, Manual of Protective Action Guides and Protective Action for Nuclear Incidents, EPA-520/1-75-001A, U.S. Environmental Protection Agency (1992). U.S. Environmental Protection Agency, Limiting Values of Radionuclide Intake and Air Concentrations and Dose Conversion Factors for Inhalation, Submersion, and Ingestion, Federal Guidance Report No. 11, EPA-520/1-88-020, U.S. Environmental Protection Agency (1988). Lewellen, " ~ u m e r i ~ a l  simulation of ANATEX Tracer Data Using a Turbulence Closure Model for Long-Range Dispersion," J. Appl. Met., 32, 929-947 (1993). 10. U.S. Environmental Protection Agency, Exrernal Exposure to Radionuclides in Air, Water, and Soil, Federal Guidance Report No. 12, EPA-402-R-93- 081, U.S. Environmental Protection Agency (1993). DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express OT implied, OT assumes any Iegal liability or responsi- bility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Refer- ence herein to any specific commercial product, process, or service by trade name, trademark, , manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recom- ' mendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those-of the United States Government or any agency thereof. Sjoreen - 3 

HASCAL -- A system for estimating contamination and doses from incidents at worldwide nuclear facilities

https://digital.library.unt.edu/ark:/67531/metadc687953/m2/1/high_res_d/41274.pdf

HASCAL -- A system for estimating contamination and doses from incidents at worldwide nuclear facilities

Abstract

Similar works

Full text

Available Versions

UNT Digital Library