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A summary of the Fire Testing Program at the German HDR Test Facility

Description: This report provides an overview of the fire safety experiments performed under the sponsorship of the German government in the containment building of the decommissioned pilot nuclear power plant known as HDR. This structure is a highly complex, multi-compartment, multi-level building which has been used as the test bed for a wide range of nuclear power plant operation safety experiments. These experiments have included numerous fire tests. Test fire fuel sources have included gas burners, wood cribs, oil pools, nozzle release oil fires, and cable in cable trays. A wide range of ventilation conditions including full natural ventilation, full forced ventilation, and combined natural and forced ventilation have been evaluated. During most of the tests, the fire products mixed freely with the full containment volume. Macro-scale building circulation patterns which were very sensitive to such factors as ventilation configuration were observed and characterized. Testing also included the evaluation of selective area pressurization schemes as a means of smoke control for emergency access and evacuation stairwells.
Date: November 1, 1995
Creator: Nowlen, S.P.
Partner: UNT Libraries Government Documents Department

Fire modeling of the Heiss Dampf Reaktor containment

Description: This report summarizes Sandia National Laboratories` participation in the fire modeling activities for the German Heiss Dampf Reaktor (HDR) containment building, under the sponsorship of the United States Nuclear Regulatory Commission. The purpose of this report is twofold: (1) to summarize Sandia`s participation in the HDR fire modeling efforts and (2) to summarize the results of the international fire modeling community involved in modeling the HDR fire tests. Additional comments, on the state of fire modeling and trends in the international fire modeling community are also included. It is noted that, although the trend internationally in fire modeling is toward the development of the more complex fire field models, each type of fire model has something to contribute to the understanding of fires in nuclear power plants.
Date: September 1995
Creator: Nicolette, V. F. & Yang, K. T.
Partner: UNT Libraries Government Documents Department

Analytical simulation of nonlinear response to seismic test excitations of HDR-VKL (Heissdampfreaktor-Versuchskreislauf) piping system

Description: The paper describes the analytical modeling, calculations, and results of the posttest nonlinear simulation of high-level seismic testing of the VKL piping system at the HDR Test Facility in Germany. One of the objectives of the tests was to evaluate analytical methods for calculating the nonlinear response of realistic piping systems subjected to high-level seismic excitation that would induce significant plastic deformation. Two out of the six different pipe-support configurations, (ranging from a stiff system with struts and snubbers to a very flexible system with practically no seismic supports), subjected to simulated earthquakes, were tested at very high levels. The posttest nonlinear calculations cover the KWU configuration, a reasonably compliant system with only rigid struts. Responses for 800% safe-shutdown-earthquake loading were calculated using the NONPIPE code. The responses calculated with NONPIPE were found generally to have the same time trends as the measurements but contained under-, over-, and correct estimates of peak values, almost in equal proportions. The only exceptions were the peak strut forces, which were underestimated as a group. The scatter in the peak value estimate of displacements and strut forces was smaller than that for the strains. The possible reasons for the differences and the effort on further analysis are discussed.
Date: January 1, 1991
Creator: Srinivasan, M.G.; Kot, C.A. (Argonne National Lab., IL (USA)) & Mojtahed, M. (Purdue Univ., Hammond, IN (USA). Dept. of Mechanical Engineering)
Partner: UNT Libraries Government Documents Department

Investigation of superstructure damping identification for the HDR containment building

Description: A method for the estimation of first mode structural damping, developed by other investigators, was applied to shaker test data of the HDR containment building. Due to inadequate precision in the experimental phase measurements no valid results could be obtained. Based on modal analysis it was also noted that for systems such as the HDR building, contributions of higher modes are not negligible as was assumed in the original approach. Therefore, the procedure for the determination of superstructure damping using experimental data was extended to include the effects of higher modes. The extended method does not lead to any higher order nonlinear equations than the first mode approximation and was found to be as simple to apply as the original approach.
Date: January 1, 1985
Creator: Hsieh, B.J.; Kot, C.A. & Srinivasan, M.G.
Partner: UNT Libraries Government Documents Department

HDR (Heissdampfreaktor) Phase 2 vibrational experiments

Description: As part of the second phase of vibrational/earthquake investigations at the HDR (Heissdampfreaktor) Test Facility in Kahl/Main, FRG, high-level shaker tests (SHAG) were performed during June and July 1986. The purpose of these experiments is to investigate full-scale structural response, soil-structure interaction, and piping and equipment response under strong excitation conditions. While global safety considerations imposed load limitations, the HDR soil/structure system was nevertheless tested to its capacity limits. The performance of up to seven different multiple support pipe hanger configurations (ranging from flexible to stiff systems) was evaluated in the tests. Data obtained in the tests serve to validate analysis methods.
Date: October 1, 1986
Creator: Malcher, L. & Kot, C.A.
Partner: UNT Libraries Government Documents Department

Numerical simulation of three-dimensional fluid-structure response

Description: Three-dimensional, coupled, fluid-structure calculations were performed for the dynamics of the core support barrel in an HDR reactor vessel during blowdown. For these calculations the three-dimensional, two-fluid code K-FIX was coupled to the three-dimensional elastic shell code FLX. The coupling procedure is described, and conditions derived from truncation error and Fourier analysis are given for numerical stability of the separate and coupled finite difference solution algorithms. The results demonstrate the importance of the coupled interactions on the structural response. A nodalization study indicates the degree of circumferential and axial resolution required for accurate results. Fine axial resolution is needed near the top built-in boundary of the core barrel to determine stresses accurately, but it is less necessary for displacements.
Date: January 1, 1979
Creator: Rivard, W.C. & Torrey, M.D.
Partner: UNT Libraries Government Documents Department

Modeling of HDR oil and cable fire tests

Description: This paper summarizes the calculations performed at Sandia National Laboratories using the COMPBRN fire model for the Heiss Dampf Reaktor (HDR) tests E41.7 and E42.2. A Sandia modified version of COMPBRN III was used for the calculations. Test E41.7 was on oil pool fire, and test E42.2 was cable fire. Both tests were conducted inside a small room within the HDR containment. Calculations were also performed for test E41.7 with the Notre Dame Fire Model. Hot gas layer temperatures and other relevant results are presented. Comparison with experimental data is made, where possible. A brief discussion on the problems encountered in the application of fire models to nuclear power plant fire modeling is also included.
Date: December 31, 1993
Creator: Nicolette, V. F. & Yang, K. T.
Partner: UNT Libraries Government Documents Department

High level seismic/vibrational tests at the HDR: An overview

Description: As part of the Phase II testing at the HDR Test Facility in Kahl/Main, FRG, two series of high-level seismic/vibrational experiments were performed. In the first of these (SHAG) a coast-down shaker, mounted on the reactor operating floor and capable of generating 1000 tonnes of force, was used to investigate full-scale structural response, soil-structure interaction (SSI), and piping/equipment response at load levels equivalent to those of a design basis earthquake. The HDR soil/structure system was tested to incipient failure exhibiting highly nonlinear response. In the load transmission from structure to piping/equipment significant response amplifications and shifts to higher frequencies occurred. The performance of various pipe support configurations was evaluated. This latter effort was continued in the second series of tests (SHAM), in which an in-plant piping system was investigated at simulated seismic loads (generated by two servo-hydraulic actuators each capable of generating 40 tonnes of force), that exceeded design levels manifold and resulted in considerable pipe plastification and failure of some supports (snubbers). The evaluation of six different support configurations demonstrated that proper system design (for a given spectrum) rather than number of supports or system stiffness is essential to limiting pipe stresses. Pipe strains at loads exceeding the design level eightfold were still tolerable, indicating that pipe failure even under extreme seismic loads is unlikely inspite of multiple support failures. Conservatively, an excess capacity (margin) of at least four was estimated for the piping system, and the pipe damping was found to be 4%. Comparisons of linear and nonlinear computational results with measurements showed that analytical predictions have wide scatter and do not necessarily yield conservative responses, underpredicting, in particular, peak support forces.
Date: December 31, 1991
Creator: Kot, C. A.; Srinivasan, M. G.; Hsieh, B. J.; Schrammel, D.; Malcher, L.; Steinhilber, H. et al.
Partner: UNT Libraries Government Documents Department

Seismic investigations of the HDR Safety Program. Summary report

Description: The primary objective of the seismic investigations, performed at the HDR facility in Kahl/Main, FRG was to validate calculational methods for the seismic evaluation of nuclear-reactor systems, using experimental data from an actual nuclear plant. Using eccentric mass shaker excitation the HDR soil/structure system was tested to incipient failure, exhibiting highly nonlinear response and demonstrating that structures not seismically designed can sustain loads equivalent to a design basin earthquake (DBE). Load transmission from the structure to piping/equipment indicated significant response amplifications and shifts to higher frequencies, while the response of tanks/vessels depended mainly on their support conditions. The evaluation of various piping support configurations demonstrated that proper system design (for a given spectrum) rather than number of supports or system stiffness is important to limiting pipe greens. Piping at loads exceeding the DBE eightfold still had significant margins and failure is improbable inspite of multiple support failures. The mean value for pipe damping, even under extreme loads, was found to be about 4%. Comparison of linear and nonlinear computational results with piping response measurements showed that predictions have a wide scatter and do not necessarily yield conservative responses underpredicting, in particular, peak support forces. For the soil/structure system the quality of the predictions did not depend so much on the complexity of the modeling, but rather on whether the model captured the salient features and nonlinearities of the system.
Date: August 1, 1994
Creator: Malcher, L.; Schrammel, D.; Steinhilber, H. & Kot, C. A.
Partner: UNT Libraries Government Documents Department

Margins for an in-plant piping system under dynamic loading

Description: The objective of this study is to verify that piping designed according to current practice does indeed have a large margin against failure and to quantify the excess capacity for piping and dynamic pipe supports on the basis of data obtained in a series of high-level seismic experiments (designated SHAM) on an in-plant piping system at the HDR (Heissdampfreaktor) Test Facility in Germany. 4 refs., 6 tabs.
Date: January 1, 1991
Creator: Kot, C.A.; Srinivasan, M.G. & Hsieh, B.J.
Partner: UNT Libraries Government Documents Department

High-level seismic tests of piping at the HDR (Heissdampfreaktor)

Description: As part of the second-phase testing at the Heissdampfreaktor (HDR) Test Facility in Kahl/Main, Federal Republic of Germany (FRG), high-level seismic experiments, designated SHAM, were performed on an in-plant piping system during the period of 19 April to 27 May 1988. The objectives of the SHAM experiments were to (1) study the response of piping subjected to seismic excitation levels that exceed design levels manifold and which may result in failure/plastification of pipe supports and pipe elements; (2) provide data for the validation of linear and nonlinear pipe response analyses; (3) compare and evaluate, under identical loading conditions, the performance of various dynamic support system, ranging from very flexible to very stiff support configurations; (4) establish seismic margins for piping, dynamic pipe supports, and pipe anchorages; and (5) investigate the response, operability, and fragility of dynamic supports and of a typical US gate valve under extreme levels of seismic excitation. A brief description of the SHAM tests is provided, followed by highlights of the test results that are given primarily in the form of maximum response values. Also presented are very limited comparisons of experimental data and pretest analytical predictions. 6 refs., 8 figs.
Date: January 1, 1989
Creator: Kot, C.A.; Srinivasan, M.G.; Hsieh, B.J. & Costello, J.F.
Partner: UNT Libraries Government Documents Department

Response of HDR-VKL piping system to seismic test excitations: Comparison of analytical predictions and test measurements

Description: As part of the earthquake investigations at the HDR (Heissdampfreaktor) Test Facility in Kahl/Main, FRG, simulated seismic tests (SHAM) were performed during April--May 1988 on the VKL (Versuchskreislauf) piping system. The purpose of these experiments was to study the behavior of piping subjected to a range of seismic excitation levels including those that exceed design levels manifold and that might induce failure of pipe supports or plasticity in the pipe runs, and to establish seismic margins for piping and pipe supports. Data obtained in the tests are also used to validate analysis methods. Detailed reports on the SHAM experiments are given elsewhere. The objective of this document is to evaluate a subsystem analysis module of the SMACS code. This module is a linear finite-element based program capable of calculating the response of nuclear power plant subsystems subjected to independent multiple-acceleration input excitation. The evaluation is based on a comparison of computational results of simulation of SHAM tests with corresponding test measurements.
Date: January 1, 1989
Creator: Srinivasan, M.G.; Kot, C.A. & Hsieh, B.J.
Partner: UNT Libraries Government Documents Department

High level seismic/vibrational tests at the HDR: An overview

Description: As part of the Phase II testing at the HDR Test Facility in Kahl/Main, FRG, two series of high-level seismic/vibrational experiments were performed. In the first of these (SHAG) a coast-down shaker, mounted on the reactor operating floor and capable of generating 1000 tonnes of force, was used to investigate full-scale structural response, soil-structure interaction (SSI), and piping/equipment response at load levels equivalent to those of a design basis earthquake. The HDR soil/structure system was tested to incipient failure exhibiting highly nonlinear response. In the load transmission from structure to piping/equipment significant response amplifications and shifts to higher frequencies occurred. The performance of various pipe support configurations was evaluated. This latter effort was continued in the second series of tests (SHAM), in which an in-plant piping system was investigated at simulated seismic loads (generated by two servo-hydraulic actuators each capable of generating 40 tonnes of force), that exceeded design levels manifold and resulted in considerable pipe plastification and failure of some supports (snubbers). The evaluation of six different support configurations demonstrated that proper system design (for a given spectrum) rather than number of supports or system stiffness is essential to limiting pipe stresses. Pipe strains at loads exceeding the design level eightfold were still tolerable, indicating that pipe failure even under extreme seismic loads is unlikely inspite of multiple support failures. Conservatively, an excess capacity (margin) of at least four was estimated for the piping system, and the pipe damping was found to be 4%. Comparisons of linear and nonlinear computational results with measurements showed that analytical predictions have wide scatter and do not necessarily yield conservative responses, underpredicting, in particular, peak support forces.
Date: January 1, 1991
Creator: Kot, C.A.; Srinivasan, M.G.; Hsieh, B.J. (Argonne National Lab., IL (United States)); Schrammel, D.; Malcher, L. (Kernforschungszentrum Karlsruhe GmbH (Germany)); Steinhilber, H. (Fachhochschule Giessen-Friedberg, Giessen (Germany)) et al.
Partner: UNT Libraries Government Documents Department

Vibrational experiments at the HDR (Heissdampfreaktor) German/US cooperation

Description: As part of an overall effort on the validation of seismic calculational methods, the US NRC/RES is collaborating with the Kernforschungszentrum Karlsruhe, FRG, in the vibrational/earthquake experiments conducted at the HDR (Heissdampfreaktor) Test Facility in Kahl/Main, FRG. In the most recent experiments (SHAG), high level excitations were produced in the HDR by means of an eccentric-mass coastdown shaker capable of developing 1000 tons of force. The purpose of the experiments was to investigate full-scale structural response, soil-structure interaction, and piping and equipment response. Data obtained in the tests serve to evaluate analysis methods. In the SHAG experiments, loadings of the HDR soil-structure system approached incipient failure levels as evidenced by high peak accelerations and displacements, local damage, nonlinear behavior, soil subsidence, and wall strains which exceeded estimated limit values. Also, the performance of different pipe hanger configurations for the VKL piping system was compared in these tests under high excitation levels. The support configurations ranged from very rigid systems (strut/snubbers) to very flexible configurations (spring and constant force supports). Pretest and post-test analyses for the building/soil and piping response were performed and are being validated with the test data.
Date: April 1, 1987
Creator: Kot, C.A.; Malcher, L. & Costello, J.F.
Partner: UNT Libraries Government Documents Department

Vibration testing and analysis of a multiply supported piping system

Description: The behavior of nuclear power plant piping systems during earthquake, and the most appropriate and economical mode of supporting such piping, is an issue of major concern. Consequently, the verification and validation of piping analysis methods and assumptions used in the design and safety assessment of nuclear power plants are of great interest. As part of its program on the validation of seismic calculational methods the US Nuclear Regulatory Commission (NRC) is specifically interested in the validation of the multiple support piping analysis module of the SMACS (Seismic Methodology Analysis Chain with Statistics) computer code. Data for the comparison of the dynamic behavior of various pipe hanger configurations and for the validation of piping response analyses were recently obtained in the large shaker experiments (SHAG) conducted at the HDR (Heissdampfreaktor) test facility in Kahl/Main, Federal Republic of Germany. This paper describes preliminary results from the SHAG piping response tests and the approach taken in the validation of the SMACS code piping analysis.
Date: January 1, 1987
Creator: Hsieh, B.J.; Kot, C.A. & Srinivasan, M.G.
Partner: UNT Libraries Government Documents Department

Comparison of analysis and vibration test results for a multiple supported piping system

Description: The behavior of a nuclear power plant piping system subjected to high level vibrational excitation is investigated experimentally and analytically. The objective is to evaluate the piping analysis method employed in the SMACS computer code. Experimental data are obtained from the Large Shaker Experiments (SHAG) conducted at the HDR Test Facility in Kahl/Main, FRG, in which the dynamic behavior of an in-plant piping system with various support configurations was investigated. Comparisons of calculational results with measured data indicate that the adequacy of the prediction depends primarily on the modeling of boundary conditions and dynamic supports. Treating the latter as rigid and using building motion as input, in general, results in under prediction of piping response. On the other hand when accelerations on the pipe side of the dynamic support attachment are used as input, piping response is highly overpredicted. Also modeling wall/floor component attachments as fixed usually leads to underprediction of amplitude as well as differences in the frequency content of response. 9 refs., 18 figs., 1 tab.
Date: January 1, 1989
Creator: Hsieh, B.J.; Kot, C.A. & Srinivasan, M.G.
Partner: UNT Libraries Government Documents Department

Vibrational experiments at the HDR (Heissdampfreaktor): SHAG results and planning for SHAM

Description: As part of the second phase of vibrational/earthquake investigations at the HDR (Heissdampfreaktor) Test Facility in Kahl/Main, FRG, high-level shaker tests (SHAG) were performed during June and July 1986 using a coast-down shaker capable of generating 1000 tons of force. The purpose of these experiments was to investigate full-scale structural response, soil/structure interaction, and piping and equipment response under strong excitation conditions. While global safety considerations imposed load limitations, the HDR soil/structure system was nevertheless tested to incipient failure. The performance of pipe support systems in as many as seven different multiple support pipe hanger configurations, ranging from flexible to stiff systems, was evaluated in the tests. Data obtained in the tests are used to validate analysis methods. The vibrational/earthquake investigations at the HDR are continuing with the SHAM experiments, planned for the spring of 1988. In these experiments the VKL piping loop will be subjected to direct multiple-point excitation at extremely high levels. The objective is to investigate different pipe support configurations at extreme loading, to establish seismic margins for piping, and to investigate possible failure/plastification modes in an in situ piping system.
Date: January 1, 1987
Creator: Kot, C.A.; Malcher, L. & Steinhilber, H.
Partner: UNT Libraries Government Documents Department

Analytical simulation of nonlinear response to seismic test excitations of HDR-VKL piping system

Description: Dynamic tests with simulated earthquake excitation (SHAM) were performed during April--May 1988 on the Versuchskreislauf (VKL) piping system at the Heissdampfreaktor (HDR) Test Facility in Kahl/Main, Federal Republic of Germany. The major objectives of these tests were to study the behavior of a full-scale in-plant piping system subjected to a range of seismic excitation levels (from design levels to those that might induce either failure of pipe supports or plasticity in the pipe runs) and to establish seismic margins for piping and pipe supports. Data obtained in the tests are also being used to validate analytical methods for piping response calculation. Detailed reports on the SHAM experiments are given elsewhere by Kot et al. (1990). This paper describes an effort to evaluate the computer code NONPIPE (proprietary to Nutech Engineers) with data from one of the SHAM tests. NONPIPE is a nonlinear finite-element program capable of calculating the elastic-plastic response of piping systems subjected to seismic excitation. The special characteristic of this code is the simplified or approximate approach it uses for modeling the elastic behavior which makes the calculations relatively less resource intensive than those of other nonlinear codes. The evaluation is based on a comparison of computational results of simulation of a SHAM test with corresponding test measurements. 6 refs., 10 figs.
Date: January 1, 1991
Creator: Srinivasan, M.G.; Kot, C.A. (Argonne National Lab., IL (United States)) & Mojtahed, M. (Purdue Univ., Hammond, IN (United States))
Partner: UNT Libraries Government Documents Department

Heavy-Section Steel Technology Program fracture issues

Description: Large-scale fracture mechanics tests have resulted in the identification of a number of fracture-technology issues. Identification of additional issues has come from the reactor vessel materials-irradiation test program and from reactor operating experience. This paper provides a review of fracture issues with an emphasis on their potential impact on a reactor vessel pressurized-thermal-shock (PTS) analysis. Mixed-mode crack propagation emerges as a major issue, due in large measure to the poor performance of existing models for the prediction of ductile tearing. Rectification of ductile tearing technology deficiencies may require extending the technology to include a more complete treatment of stress-state and loading history effects. The effect of cladding on vessel fracture remains uncertain to the point that it is not possible to determine at this time if the net effect will be positive or negative. Enhanced fracture toughness for shallow flaws has been demonstrated for low-strength structural steels. Demonstration of a similar effect in reactor pressure vessel steels could have a significant beneficial effect on the probabilistic analysis of reactor vessel fracture. Further development of existing fracture-mechanics models and concepts is required to meet the special requirements for fracture evaluation of circumferential flaws in the welds of ring-forged vessels. Fracture technology advances required to address the issues discussed in this paper are the major objective for the ongoing Heavy-Section Steel Technology (HSST) Program at Oak Ridge National Laboratory (ORNL). 22 refs., 18 figs.
Date: January 1, 1991
Creator: Pennell, W.E.
Partner: UNT Libraries Government Documents Department

Analytical simulation of seismic testing of VKL (Versuchskreislauf) piping system at the HDR (Heissdampfreaktor) Test Facility

Description: Dynamic tests with simulated earthquake excitation (SHAM) were performed during April--May 1988 on the VKL (Versuchskreislauf) piping system at the HDR (Heissdampfreaktor) Test Facility in Kahl/Main, Federal Republic of Germany. The major objectives of these test were to study the behavior of a full-scale in-plant piping system subjected to a range of seismic excitation levels, from design levels to those that exceed design levels manifold and those that might induce failure of pipe supports or plasticity in the pipe runs, and to establish seismic margins for piping and pipe supports. Data obtained in the tests are also being used to validate analytical method for piping response calculation. Detailed reports on the SHAM experiments are given elsewhere. The paper describes an effort to evaluate the subsystem analysis module of the SMACS code using some of the SHAM test data. The SMACS modules a linear finite-element program, derived from the SAP4 code and capable of calculating the response of nuclear power plant subsystems subjected to multiple, independent acceleration excitation. The evaluation is based on a comparison of computational results of simulation of SHAM test with corresponding test measurements. 4 refs., 7 figs., 2 tabs.
Date: January 1, 1990
Creator: Srinivasan, M.G.; Kot, C.A. & Hsieh, B.J.
Partner: UNT Libraries Government Documents Department