Suchergebnisse

During postulated high-pressure core melt accident scenarios, temperature values of more than 800°C can be reached in the reactor coolant line and the surge line of a pressurised water reactor (PWR), before the bottom of the reactor pressure vessel experiences a significant temperature increase due to core melting. For the assessment of components of the primary cooling circuit, two methods are used by GRS. One is the simplified method ASTOR (approximated structural time of rupture). This method employs the hypothesis of linear damage accumulation for modeling damage progression. A failure time surface which is generated by structural finite element (FE) analysis of varying pressure and temperature loads serves as a basis for estimations of failure times. The second method is to perform thermohydraulic and structure mechanic calculations for the accident scenario under consideration using complex calculation models. The paper shortly describes both assessment procedures. Validation of the ASTOR method concerning a large-scale test on a pipe section with geometric properties similar to a reactor coolant line is presented as well as severe accident scenarios investigated with both methods.

Anomalous Microwave Emission (AME) is a significant component of Galactic diffuse emission in the frequency range 10–60GHz and a new window into the properties of sub-nanometre-sized grains in the interstellar medium. We investigate the morphology of AME in the ≈10○ diameter λ Orionis ring by combining intensity data from the QUIJOTE experiment at 11, 13, 17, and 19GHz and the C-Band All Sky Survey (C-BASS) at 4.76GHz, together with 19 ancillary data sets between 1.42 and 3000GHz. Maps of physical parameters at 1○ resolution are produced through Markov chain Monte Carlo (MCMC) fits of spectral energy distributions (SEDs), approximating the AME component with a lognormal distribution. AME is detected in excess of 20σ at degree-scales around the entirety of the ring along photodissociation regions (PDRs), with three primary bright regions containing dark clouds. A radial decrease is observed in the AME peak frequency from ≈35GHz near the free–free region to ≈21GHz in the outer regions of the ring, which is the first detection of AME spectral variations across a single region. A strong correlation between AME peak frequency, emission measure and dust temperature is an indication for the dependence of the AME peak frequency on the local radiation field. The AME amplitude normalized by the optical depth is also strongly correlated with the radiation field, giving an overall picture consistent with spinning dust where the local radiation field plays a key role. ; Partial financial support for QUIJOTE is provided by the Spanish Ministry of Economy and Competitiveness (MINECO) under the projects AYA2007-68058-C03-01, AYA2010-21766-C03-02, AYA2014-60438-P, AYA2017-84185-P, IACA13-3E-2336, IACA15-BE-3707, and EQC2018-004918-P; Agencia Estatal de Investigación (AEI) and Fondo Europeo de Desarrollo Regional (FEDER, UE), under projects ESP2017-83921-C2-1-R and AYA2017-90675-REDC; the European Union's Horizon 2020 research and innovation programme under grant agreement number 687312 (RADIOFORE; FP acknowledges support from the Spanish Ministerio de Ciencia, Innovación y Universidades (MICINN) under grant numbers ESP2015-65597-C4-4-R, ESP2017-86852-C4-2-R, ESP2015-65597-C4-4-R, and ESP2017-86852-C4-2-R. GROUNDS) and number 658499 (PolAME); Unidad de Excelencia María de Maeztu (MDM-2017-0765) ; Peer reviewed