[en] The effect of reactor graphite nuclear-physical property change, caused by burnup of empurities present in it (N, B, Ca, H2, MnTiV rare earths) are on the RBMK-1000 performances is evaluated. Expression, describing the dependence of reactor graphite absorption complete effective microscopic cross section on reactor operation time is derived. The conclusion is drawn, that because of the graphite high nuclear density and large capture cross sections the impurities making up thousands of percent, influence significantly the accuracy of the RBMK-1000 cell neutron-physical calculation. Impurity composition changing at the expence of burnup leads to the change in thermal neutron macroscopic absorption cross section in the reactor cell approximately by 1.2%, which appears to be the source of a sysetematic error in calculations, made without taking into account the impurity burnup. Impurity burnup accounting allows to define more pricisely reactor operation performance: irradiated fuel burnup practically appears to be 4.7% higher; the fuel loading rate is 4.4% lover and the fuel consumption is 4.4% less
Journal
No abstract available
Source
Federal'noe Agentstvo po Atomnoj Ehnergii, Moscow (Russian Federation); Federal'noe Gosudarstvennoe Unitarnoe Predpriyatie Opytnoe Konstruktorskoe Byuro GIDROPRESS, Podol'sk, Moskovskaya Obl. (Russian Federation); 121 p; ISBN 978-5-94883-072-8; 
; 2007; p. 93; 5. International scientific and technical conference Safety assurance for NPP with WWER; 5-ya Mezhdunarodnaya nauchno-tekhnicheskaya konferentsiya Obespechenie bezopasnosti AEhS s VVEhR; Podol'sk, Moskovskaya Obl. (Russian Federation); 29 May - 1 Jun 2007
; 2007; p. 93; 5. International scientific and technical conference Safety assurance for NPP with WWER; 5-ya Mezhdunarodnaya nauchno-tekhnicheskaya konferentsiya Obespechenie bezopasnosti AEhS s VVEhR; Podol'sk, Moskovskaya Obl. (Russian Federation); 29 May - 1 Jun 2007
[en] The paper compares the parameters of four types of clinical whole-body spectrometers (eight-crystal spectrometer - four crystals above and four crystals under the patient; two-crystal spectrometer with linear scanning geometry; two-crystal spectrometer with spiral scanning geometry and with a possible termination and without any termination of the forward probe movement at the ends of the phantom) from the point of view of two basic characteristics required of such spectrometers: (1) The spectrometer should have uniform spatial sensitivity, i.e. pulse counts should be independent of isotope localization in the organism; (2) It should have maximum sensitivity relative to the number of detectors required for meeting the first requirement. An M-20 computer was used for calculating the efficiency of counting the primary gamma radiation from isotropic point sources of 125I, 141Ce, 51Cr, 131I, 137Cs, 60Co, and 40K placed at 13 points of each of the 18 sections (every 10 cm) of a water-filled elliptical cylinder 180 cm in length and with 36 cm and 20 cm axes, for the four above-mentioned measurement geometries. Results were obtained for different measurement geometries. The calculations were verified experimentally by an eight-crystal spectrometer.From an analysis of the results, the optimum measurement geometry for the four types of spectrometers was determined. It is shown that the uniformity of spatial sensitivity can be considerably improved if the entire spectrum of gamma radiation from the phantom is recorded. (author)
[ru]
V rabote sravnivajutsja parametry chetyreh tipov klinicheskih spektrometrov izluchenij cheloveka (vos'mikristal'nyj spektrometr — chetyre kristalla nad pacientom i chetyre pod pacientom, dvuhkristal'nyj spektrometr s geometriej linejnogo skennirovanija i dvuhkristal'nye spektrometry s geometriej spiral'nogo skennirovanija s ostanovkoj i bez ostanovki postupatel'nogo dvizhenija datchika na koncah fantoma) s tochki zrenija dvuh osnovnyh trebovanij, predjavljaemyh k takim spektrometram: 1) spektrometr dolzhen imet' odnorodnuju prostranstvennuju chuvstvitel'nost', t.e. nezavisimost' chisla soschitannyh impul'sov ot lokalizacii izotopa v organizme; 2) spektrometr dolzhen imet' maksimal'nuju chuvstvitel'nost' pri kolichestve detektorov, obespechivajushhih vypolnenie pervogo trebovanija. Na JeCVM-20 byli rasschitany jeffektivnosti registracii pervichnogo gamma-izluchenija tochechnyh izotropnyh istochnikov 125I, 141Ce, 51Cr, 131I, 137Cs, 60Co, 40K, raspolozhennyh v 13 tomkah kazhdogo iz 18 sechenij (cherez 10 sm) vodonapolnennogo jellipticheskogo cilindra dlinoj 180 sm i razmerom osej 36 i 20 sm dlja chetyreh nazvannyh geometrij izmerenij. Polucheny rezul'taty dlja razlichnyh geometricheskih uslovij izmerenij. Rezul'taty nekotoryh raschetov proverjalis' jeksperimental'no na vos'mikristal'nom spektrometre. Analiz poluchennyh rezul'tatov pozvolil opredelit' optimal'nuju geometriju izmerenij dlja chetyreh ukazannyh tipov spektrometrov. Pokazano, chto odnorodnost' prostranstvennoj chuvstvitel'nosti mozhet byt' sushhestvenno uluchshena, esli registrirovat' polnyj spektr vyhodjashhego iz fantoma gamma-izluchenija. (author)Source
International Atomic Energy Agency, Vienna (Austria); 760 p; Jun 1971; p. 579-590; Symposium on New Developments in Physical and Biological Radiation Detectors; Vienna (Austria); 23-27 Nov 1970; IAEA-SM--143/63; ISSN 0074-1884; ; 8 refs., 9 figs.; This record replaces 44082513
; 8 refs., 9 figs.; This record replaces 44082513
No abstract available
Source
Ministerstvo Obrazovaniya i Nauki Rossijskoj Federatsii, Moscow (Russian Federation); Gosudarstvennaya Korporatsiya po Atomnoj Ehnergii Rosatom, Moscow (Russian Federation); Natsional'nyj Issledovatel'skij Yadernyj Univ. MIFI, Moscow (Russian Federation); 300 p; ISBN 978-5-7262-1786-4; ; 2013; p. 58; Scientific session of NRNU MEPHI-2013; Nauchnaya sessiya NIYaU MIFI-2013; Moscow (Russian Federation); 2013
; 2013; p. 58; Scientific session of NRNU MEPHI-2013; Nauchnaya sessiya NIYaU MIFI-2013; Moscow (Russian Federation); 2013