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Honkamaa, Tapani

Publications and source records attributed to Honkamaa, Tapani.

5 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Passive methods for spent fuel characterisation at the Finnish geological repository

Development of the Passive Gamma Emission Tomography (PGET) and Passive Neutron Albedo Reactivity (PNAR) methods in the context of the Finnish geological repository for spent nuclear fuel has shown that they provide, for BWR fuel assemblies, the comprehensive verification needed to meet the nuclear safeguards objectives of the repository. The principles of the PGET and PNAR methods and the design and operation of the respective instruments are presented. A few results from measurements at the spent fuel storage pools at the Finnish nuclear power plants are discussed. The directions of ongoing and future developments are indicated.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗
DOE OSTI2021

Analysis of PNAR Spent Fuel Safeguards Measurements using the ORIGEN Data Analysis Module

This paper summarizes the analysis of the Passive Neutron Albedo Reactivity (PNAR) measurements using the ORIGEN data analysis module for 23 boiling water reactor spent fuel assemblies that were performed in Finland under an international collaboration on spent fuel safeguards verification methods. PNAR is part of the proposed integrated nondestructive system to be used for safeguards verifications at the planned Finnish encapsulation facility. Besides measuring passive neutron and gamma emission rates from an assembly like a Fork detector, PNAR also measures the PNAR ratio, which is expected to correlate with the fissile content in the assembly. The emission rates and PNAR ratio can be used to verify the operator declarations and the fissile content of an assembly, respectively. The analysis was performed using the ORIGEN Data Analysis Module, which was originally developed for predicting Fork detector neutron and gamma signals for spent fuel measurements and has been integrated into the Integrated Review and Analysis Package developed by Euratom and the IAEA. The Module includes the ORIGEN burnup analysis code and integrates detector response functions pre-generated using MCNP to predict detector signals in several seconds per assembly. In this study, new response functions specific to PNAR measurements were generated for ORIGEN Module. The study also analyzes impacts of using detailed fuel design and operation information vs. standard safeguards information on results calculated by ORIGEN Module. Using detailed information reduced the standard deviation of relative differences between calculated and measured neutron count rates among the 23 assemblies from ~10% to ~4%. The results obtained using standard safeguards information for these PNAR measurements were similar to those obtained for the Fork detector. A clear trend was found between the calculated net neutron multiplications and the measured PNAR ratios of the 23 assemblies. This paper describes how ORIGEN Module calculates the expected PNAR neutron and gamma signals and PNAR ratio and how they compare with corresponding measured values.

Ilas, Germina↗
DOE OSTI2019

PNAR Measurement Report

STUK performed an NDA inspection at the spent fuel interim storage facility at Olkiluoto NPP during 22.7-26.7.2019. The inspection was also attended by experts from US DOELANL, Helsinki Institute of Physics, Euratom and IAEA and was made possible by the operators from TVO. The inspection included fuel verification with STUK’s new PNAR instrument and IAEA’s PGET. Simultaneous measurements were made possible with a support quadropod common for both instruments. The inspection and the results of the PGET verification are described in separate memorandums. This report focuses on the results of the PNAR verification. The inspection was the very first one performed with STUK’s PNAR instrument. Thus, the main goal of the inspection from the PNAR point-of-view was to demonstrate that the PNAR method works in practice, identify possible improvements and assess if PNAR can be utilized in SNF verification. Furthermore, the measurement campaign was an initial step in exploring the fuel parameter range where PNAR could be used and an initial investigation into quantifying the uncertainties of the system.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗