Nuclear technology

In this work an X-ray pho toelectron spec troscopy study of ni trates Th(NO 3 ) 4 ×4H 2 O, UO 2 (NO 3 ) 2 ×nH 2 O, Pu(NO 3 ) 4 ×nH 2 O, and Am(NO 3 ) 2 ×nH 2 O was done in the binding energy range from 0 to 1000 eV in order to draw a correlation of the fine spectral structure param e ters with the ac ti nide ions ox i da tion states, close en vi ron ment struc ture, and chem i cal bond na ture. The lin earity of the dependence of the An5f n line in tensity on the num ber n 5f of the An5f electrons was proven to remain up to the Am 3+ ion with the elec tron configura-tion{Rn 5f 6 . The spectral structure in the binding en ergy range from 0 to~15 eV was as sociated with the formation of the outer valence mo lecular orbitals due to the in teraction of the An6d-, 7s, 5f -O2p elec trons, and the fine spec tral structure in the binding en ergy range from~15 to ~50 eV -with the for mation of the in ner valence molecular orbitals due to the interaction of the An6p -O2s elec trons from the filled neigh boring atomic orbitals of actinide and oxygen in the studied com pounds. The fine structure of the core level elec tron spectra in the binding en ergy range from~50 to 1000 eV was shown to correlate with the actinide ion ox i da tion state.

This paper addresses the following observation: in Japan, in the East, as much as in the West, there is one same divide, the one separating art from science – or more broadly – separating the humanities from the modern sciences.

My argument is, on the one hand, that to analyze this divide constitutes one way of solving some of the challenges of the 21st century - one of which relating to national identities.

On the other hand, and most importantly, I wish to demonstrate that, in spite of the divide, the two disciplines, as much as the East and the West, have more in common than commonly assumed and that this divide, even if profound, is not so radical.

The Kilopower Project was initiated by NASA's Space Technology Mission Directorate/ Game Changing Development Program in fiscal year 2015 to demonstrate subsystem-level technology readiness of small space fission power in a relevant environment (Technology Readiness Level 5) for space science and human exploration power needs. The Kilopower Project centerpiece is the Kilowatt Reactor Using Stirling TechnologY (KRUSTY) test, which consists of the development and testing of a ground technology demonstrator of a 1-kW(electric)-class fission power system (FPS). The technologies to be developed and validated by KRUSTY are extensible to space FPSs from 1 to 10 kW(electric), which can enable modular surface FPSs for human exploration as well as higherpower future potential deep space science missions. The KRUSTY demonstration is cofunded by NASA and the U.S. Department of Energy National Nuclear Security Administration. The KRUSTY demonstration in the National Critical Experiment Research Center's Device Assembly Facility was completed in the first quarter of 2018.

Undoubtedly, energy production and their sustained growth constitute a relevant factor for ensuring the economic and social development of any country. Considering the different available energy sources that the world can use to satisfy the foreseeable increase in energy demand in the coming years, particularly for the production of electricity, at least for the next decades there are only a few realistic options available to reduce further the CO 2 emissions, to satisfy the foreseeable demand of electricity, and to have a secure supply of energy. One of these options is the use of nuclear energy for electricity generation. If this is true, then, why the public opinion of several countries is against the use of this type of energy sources? One of the reasons is the negative impact of an accident at a nuclear power plant for the human beings and for the environment. The second reason is the possible military uses of certain nuclear installations used for the generation of electricity. The third reason is the nuclear waste generated by nuclear power plants.

This pa per de scribes the ap pli ca tion of SRNA Monte Carlo pack age for pro ton transport sim u la tions in com plex ge om e try and dif fer ent ma te rial com po si tion. SRNA pack age was de vel oped for 3D dose dis tri bu tion cal cu la tion in pro ton ther apy and dosim e try and it was based on the the ory of mul ti ple scat ter ing. The com pound nu clei de cay was sim u lated by our own and the Rus sian MSDM mod els us ing ICRU 63 data. The de vel oped pack age con sists of two codes: SRNA-2KG, which sim u lates pro ton trans port in the com bi na torial ge om e try and SRNA-VOX, which uses the voxelized ge om e try us ing the CT data and con ver sion of the Hounsfield's data to tis sue el e mental com po si tion. Tran si tion prob a bil i ties for both codes are pre pared by the SRNADAT code. The sim u la tion of pro ton beam char ac ter iza tion by Multi-Layer Far a day Cup, spa tial dis tri bu tion of pos i tron emit ters ob tained by SRNA-2KG code, and intercomparison of com pu ta tional codes in ra di a tion do sim e try, in di cate the imme di ate ap pli ca tion of the Monte Carlo tech niques in clin i cal prac tice. In this pa per, we briefly pres ent the phys i cal model im ple mented in SRNA pack age, the ISTAR proton dose plan ning soft ware, as well as the re sults of the nu mer i cal ex per i ments with pro ton beams to ob tain 3D dose dis tri bu tion in the eye and breast tu mor.

The objective of this work was to assess the potential of thorium based fuel to minimise Pu and MA production in Pressurised Water Reactors (PWRs). The assessment was carried out by examining destruction rates and residual amounts of Pu and MA in the fuel used for transmutation. In particular, sensitivity of these two parameters to the fuel lattice Hydrogen to Heavy Metal (H/HM) ratio and to the fuel composition was systematically investigated. All burn-up calculations were performed using CASMO4 -the fuel assembly burn-up code. The results indicate that up to 1 000 kg of reactor grade Pu can potentially be burned in thorium based fuel assemblies per GW e Year. Up to 75% of initial Pu can be destroyed per path. Addition of MA to the fuel mixture degrades the burning efficiency. The theoretically achievable limit for total TRU destruction per path is 50%. Efficient MA and Pu destruction in thorium based fuel generally requires a higher degree of neutron moderation and, therefore, higher fuel lattice H/HM ratio than typically used in the current generation of PWRs. Reactivity coefficients evaluation demonstrated the feasibility of designing a Th-Pu-MA fuel with negative Doppler and moderator temperature coefficients.

The gas-cooled fast reactor (GCFR) is regarded as the primary candidate for a future sustainable nuclear power system. In this paper a general core layout is presented for a 2400-MW(thermal) GCFR. Two fuel elements are discussed: a TRISO-based coated particle and the innovative hollow sphere concept. Sustainability calls for recycling of all minor actinides (MAs) in the core and a breeding gain close to unity. A fuel cycle is designed allowing operation over a long period, requiring refueling with ²³⁸U only. The evolution of nuclides in the GCFR core is calculated using the SCALE system (one-dimensional and three-dimensional). Calculations were done over multiple irradiation cycles including reprocessing. The result is that it is possible to design a fuel and GCFR core with a breeding gain around unity, with recycling of all MAs from cycle to cycle. The burnup reactivity swing is small, improving safety. After several fuel batches an equilibrium core is reached. MA loading in th...

This report assesses the economics of reprocessing versus direct disposal of spent nuclear fuel. The breakeven uranium price at which reprocessing spent nuclear fuel from existing light-water reactors (LWRs) and recycling the resulting plutonium and uranium in LWRs would become economic is assessed, using central estimates of the costs of different elements of the nuclear fuel cycle (and other fuel cycle input parameters), for a wide range of range of potential reprocessing prices. Sensitivity analysis is performed, showing that the conclusions reached are robust across a wide range of input parameters. The contribution of direct disposal or reprocessing and recycling to electricity cost is also assessed. The choice of particular central estimates and ranges for the input parameters of the fuel cycle model is justified through a review of the relevant literature. The impact of different fuel cycle approaches on the volume needed for geologic repositories is briefly discussed, as are the issues surrounding the possibility of performing separations and transmutation on spent nuclear fuel to reduce the need for additional repositories. A similar analysis is then performed of the breakeven uranium price at which deploying fast-neutron breeder reactors would become competitive compared with a once-through fuel cycle in LWRs, for a range of possible differences in capital cost between LWRs and fast-neutron reactors. Sensitivity analysis is again provided, as are an analysis of the contribution to electricity cost, and a justification of the choices of central estimates and ranges for the input parameters. The equations used in the economic model are derived and explained in an appendix. Another appendix assesses the quantities of uranium likely to be recoverable worldwide in the future at a range of different possible future prices.

The technical and economic aspects of the use of molybdenum depleted in the isotope 95 Mo (DepMo) for the transmutation of actinides in a light water reactor are discussed. DepMo has a low neutron absorption cross section and good physical and chemical properties. Therefore, DepMo is expected to be a good inert matrix in ceramic-metal fuel. The costs of the use of DepMo have been assessed, and it was concluded that these costs can be justified for the transmutation of the actinides neptunium, americium, and plutonium. *

The pa per de scribes the pro ce dure of adapt ing a co ax ial high-pre ci sion ger ma nium de tector to a de vice with nu mer i cal cal i bra tion. The pro ce dure in cludes the de ter mi na tion of de tec tor di men sions and es tab lish ing the cor re spond ing model of the sys tem. In or der to achieve a suc cess ful cal i bra tion of the sys tem with out the us age of stan dard sources, Monte Carlo sim u la tions were per formed to de ter mine its ef fi ciency and pulse-height response func tion. A de tailed Monte Carlo model was de vel oped us ing the MCNP-5.0 code. The ob tained re sults have in di cated that this method rep re sents a valu able tool for the quan ti ta tive un cer tainty anal y sis of ra di a tion spec trom e ters and gamma-ray de tec tor cal i bra tion, thus min i miz ing the need for the de ploy ment of ra dio ac tive sources. Key words: gamma-ray spec trom e try, HPGe mod el ing, sourceless cal i bra tion, Monte Carlo meth od Nu clear Tech nol ogy & Ra di a tion Protection Sci en tific pa per

This pa per pres ents an over view of the "scal ing strat egy", in par tic u lar the role played by the coun ter part test meth od ol ogy. The re cent stud ies deal ing with a scal ing anal y sis in light wa ter reactor with spe cial re gard to the VVER 1000 Rus sian re ac tor type are pre sented to dem on strate the phe nom ena im por tant for scal ing. The adopted scal ing ap proach is based on the se lec tion of a few char ac ter is tic pa ram e ters cho sen by tak ing into ac count their rel e vance in the be hav ior of the tran sient. The adopted com puter code used is RELAP5/Mod3.3 and its ac cu racy has been dem on strated by qual i ta tive and quan ti ta tive eval u a tion. Com par ing ex per i men tal data, it was found that the in ves ti gated fa cil i ties showed sim i lar be hav ior con cern ing the time trends, and that the same ther mal hy drau lic phenom ena on a qual i ta tive level could be pre dicted. The main re sults are: PSB and LOBI main pa ram e ters have sim i lar trends. This fact is the con fir ma tion of the va lid ity of the adopted scal ing ap proach and it shows that PWR and VVER re ac tor type be hav ior is very sim i lar. No new phe nom ena oc curred dur ing the coun ter part test, de spite the fact that the two fa cil i ties had a dif fer ent lay out, and the al ready known phe nom ena were pre dicted cor rectly by the code. The code ca pa bil ity and ac cu racy are scale-in de pendent. Both char ac ter is tics are nec es sary to per mit the full scale cal cu la tion with the aim of nu clear power plant be hav ior pre dic tion.

North Korea had always desire to have nuclear weapons since its establishment and the United States nuclear missiles deployment in South Korea had established ground to begun the nuclear program during the Cold War period.  North Korea utilized the competition between the Soviets and Americans by taking the support of the Soviet Union for the nuclear energy program and training of nuclear scientists. The common security perceptions against the U.S. were a good chance for the Democratic People's Republic of Korea (DPRK) regime but the collapse of the Soviet Union would concern North Korea by catalyzing its nuclear ambitions.
      United States administration tried to stop its nuclear program via peaceful cooperation starting with the 1990s. There were held more than 100 negotiations between the U.S. and North Korea until 2000.  All these bilateral efforts yield no result for the denuclearization of the Korean peninsula. The last solution was the multilateral organization with the Six-Party Talks in 2003. The talks ended in 2009 with the North Korean foreign minister statement: ‘’We will never again take part in such talks  ... We have no choice but to further strengthen our nuclear deterrent  ... The DPRK will bolster its nuclear deterrence for self-defense in every way ’’ Afterwards, North Korea rapidly augmented its nuclear activities by improving its technologies. While there were 21 nuclear missiles provocations during the Six-Party Talks era, these provocations increased to 93 between 2010 and 2020 as it continues today. 
        The history and process demonstrate how the DPRK regime bent upon its nuclear program and its nuclearization not prevented despite many negotiation efforts and pressures. In this context, the paper will argue that the denuclearization of North Korea is highly unlikely. The argument will support under four main topics: (1) the concentration of DPRK’s military power on the nuclear warheads; (2) unpreventable economic and technical sources of North Korea and ineffectiveness of the international sanctions; (3) the increasing of the U.S. and China competition in the East Asia region; (4) their different solutions for the denuclearization and the Chinese security dilemma. Therefore, the essay will analyze the argument from the domestic, regional, and international perspectives.

The pros pect of manned space mis sions out side Earth's or bit is lim ited by the travel time and shield ing against cos mic ra di a tion. The chem i cal rock ets cur rently used in the space pro gram have no hope of pro pel ling a manned ve hi cle to a far away lo ca tion such as Mars due to the enor mous mass of fuel that would be re quired. The spe cific en ergy avail able from nu clear fuel is a fac tor of 10 6 higher than chem i cal fuel; it is there fore ob vi ous that nu clear power pro duc tion in space is a must. On the other hand, re cent considerrations to send a man to the Moon for a long stay would re quire a sta ble, secured, and safe source of en ergy (there is hardly any thing be yond nu clear power that would pro vide a use ful and re li ably safe sus tain able sup ply of en ergy). Na tional Aeronau tics and Space Ad min is tra tion (NASA) an tic i pates that the mass of a shield ing mate rial re quired for long travel to Mars is the next ma jor de sign driver. In 2006 NASA iden ti fied a need to as sess and eval u ate po ten tial gaps in ex ist ing knowl edge and under stand ing of the level and types of ra di a tion crit i cal to as tro nauts' health dur ing the long travel to Mars and to start a com pre hen sive study re lated to the shield ing de sign of a space craft find ing the con di tions for the mit i ga tion of ra di a tion com po nents contrib ut ing to the doses be yond ac cepted lim its. In or der to re duce the over all space craft mass, NASA is look ing for the novel, multi-pur pose and multi-func tional ma te ri als that will pro vide ef fec tive shield ing of the crew and elec tron ics on board. The Lab o ra tory for Neutronics and Ge om e try Com pu ta tion in the School of Nu clear En gi neer ing at Purdue Uni ver sity led by Prof. Tatjana Jevremovic be gan in 2004 the an a lyt i cal eval u a tions of dif fer ent light weight ma te ri als. The pre lim i nary re sults of the de sign sur vey study are pre sented in this pa per. Key words: long mis sion to space, cos mic ra di a tion, shield ing, Monte Carlo method, ra di a tion trans port Sci en tific pa per UDC: 629.785:539.12 BIBLID: 1451-3994, 21 (2006), 2, pp. 47-66 Au thors' ad dress: School of Nu clear En gi neer ing, Purdue Uni ver sity West La fay ette, IN 47907, USA E-mail ad dress of cor re spond ing au thor: [email protected] (T. Jevremovic) 50 Nu clear Tech nol ogy & Ra di a tion Pro tec tion -2/2006

The Canadian Nuclear Safety Commission recently developed the CANTIA (CANDU TM Tube Inspection Assessment) methodology for probabilistic assessment of inspection strategies for steam generator (SG) tubes as a direct effect on the early detection and prevention of tube failure and primary-to-secondary leak of reactor coolant. In an effort to improve CANTIA, an SG tube integrity assessment code, a relevant survey of the literature on the discharge of subcooled water from cracks and critical flow models, SG tube cracks, leakage, and probabi-listic assessment methodologies was carried out. The original CANTIA and ANL /CANTIA code models for the flaw opening area and flow leakage rate were reviewed. The predictions from the crack opening area and the leakage flow rate models were compared with experimental measured data from cracked SG tubes.

1 Rus sian Re search Cen tre "Kurchatov In sti tute", Mos cow, Rus sia 2 In sti tute of Solid State Chem is try of the Ural De part ment of Rus sian Acad emy of Sci ences, Ekaterinburg, Rus sia 3 In sti tute of Metal Phys ics of the Ural Branch of the Rus sian Acad emy of Sci ences, Ekaterinburg, Rus sia Sci en tific pa per

Aunque la alianza entre ciencia y tecnología (CyT) ha sido prácticamente indisociable del progreso y el bienestar económico desde tiempos antiguos (Krige y Barth, 2006), es a partir de la Segunda Guerra Mundial (SGM) que se evidencia la inevitabilidad de considerarlas como parte importante de las Relaciones Internacionales (RI). Curiosamente, sin embargo, aunque muchos autores de teoría de las RI consideran los avances en CyT como elementos significativos a la hora de definir y redefinir el mapa de la distribución de poder en el Sistema Internacional (SI), no se ha teorizado tan ampliamente sobre su rol específico en él (Skolnikoff, 1993; Weiss, 2005; Krige y Barth, 2006; McCarthy, 2015), y mucho menos desde los países en desarrollo o (semi)periféricos. De esta forma, se ignora un componente central de la (re)distribución de poder en el SI generado por el reacomodo, en gran medida, de las capacidades materiales de los Estados, debido en buena parte a avances científicos, técnicos, e innovativos. La SGM evidenció tal reacomodamiento instaurando a Estados Unidos y a la Unión de Repúblicas Socialistas Soviéticas (URSS) como vencedores indiscutibles, y al primero como la principal potencia en materia militar gracias al monopolio del secreto atómico, al menos hasta 1949.
A partir de ese momento, la disciplina de las RI se centró en la formulación de teorías que en gran parte giraron, por ejemplo, en torno al poder estabilizador o desestabilizador de la presencia de armamento nuclear en el mundo (tecnología que logró poner en evidencia la importancia de la CyT en las agendas públicas), y si bien los usos de esta tecnología han sido cuestionados durante varias décadas, no se puede soslayar el hecho de que ha representado un punto de inflexión a la hora de pensar los vínculos internacionales tanto en su faceta teórica como práctica.
Enfocarse en los cambios generados por las aplicaciones en CyT en los Estados, y especialmente en la relación entre ellos, no significa caer en los determinismos según los cuales la posesión de capacidades científico-tecnológicas se traducen directa y linealmente en bienestar nacional y poder internacional; pero sí implica reconocer que las nuevas capacidades en CyT generaron articulaciones que se expresaron en una mayor incidencia en la arquitectura del SI de procesos tales como la conformación de instituciones y organizaciones internacionales a partir del establecimiento de acuerdos bi y/o multilaterales, que tuvieron como objetivo armonizar múltiples voces y gestionar sus diversos intereses conflictivos, en torno a la conformación de regímenes internacionales específicos de control de tecnología. Es en este sentido especialmente, que los países ven limitadas y / o incentivadas sus políticas de CyT domésticas y al mismo tiempo, buscan proyectar sus capacidades haciendo uso de la Política Exterior propia en el campo de las RI en CyT. Esta presentación busca invitar a explorar superficialmente algunos de los aspectos mencionados, por medio del análisis del papel jugado por la tecnología nuclear desde su irrupción en el SI.

In re cent years, re search con ducted in the US and in It aly has dem on strated pro duction of ra dio iso topes in plasma fo cus de vices, and par tic u larly, on what could be termed "en dog e nous" pro duc tion, to wit, pro duc tion within the plasma it self, as opposed to ir ra di a tion of tar gets. This tech nique re lies on the for ma tion of lo cal ized small plasma zones char ac ter ized by very high den si ties and fairly high tem per a tures. The con di tions pre vail ing in these zones lead to high nu clear re ac tion rates, as pointed out in pre vi ous work by sev eral au thors [1, 2, 3, 4]. Fur ther in ves ti ga tion of the cross sec tions in volved has proven nec es sary to model the phe nom ena in volved. In this paper, the pres ent sta tus of re search in this field is re viewed, both with re gards to cross sec tion mod els and to ex per i men tal pro duc tion of ra dio iso topes. Pos si ble out comes and fur ther de vel op ment are dis cussed.

In the case of a hypothetical severe accident in a nuclear power plant, iodine is one of the fission products of major importance. It may be present in various gas-eous forms that could be released to the environment, impacting population health. In such a case, the amount released (the so-called "source term") has to be esti-mated in order to help the safety authorities protect the population from radiological consequences. This estima-tion is one of the main objectives of the Accident Source Term Evaluation Code (ASTEC) that is developed jointly by the French Institut de Radioprotection et de Sûreté Nucléaire (IRSN) and the German institute Gesellschaft für Anlagen-und Reaktorsicherheit. ASTEC is composed of various modules able to model the nuclear reactor behavior during an accident. One of these modules, named IODE, predicts iodine behavior in the reactor contain-ment. It is able to model the kinetics of about 35 chemical reactions and mass transfer processes. IODE is...

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1 Rus sian Re search Cen tre "Kurchatov In sti tute", Mos cow, Rus sia 2 In sti tute of Ge ol ogy of Ore De po si tions of RAS, Mos cow, Rus sia 3 Mos cow NPO "Ra don", Mos cow, Rus sia Sci en tific pa per Two pyrochlore ce ramic sam ples were stud ied in this work. The X-ray dif frac tion and the scanning elec tron mi cros copy showed that the ce ram ics with the cal cu lated com po si tion CaThSn 2 O 7 was formed by the dom i nat ing pyrochlore phase with the traces of thoria nite and he ma tite, while the CaThZr 2 O 7 ce ram ics -by the dom i nat ing pyrochlore phase with the mi nor ad mix tures of thoria nite and perovskite. The real com po si tions of pyrochlore phases de termined by the scaning elec tron mi cros copy are Ca 0.88 Th 0.92 Sn 2 O 6.72 and Ca 0.84 Th 0.80 Zr 2 O 6.44 .

The re sults of ex per i men tal test ing of the dig i tal mul ti chan nel an a lyzer which digitalizes the sig nal af ter a preamplifier are pre sented. The re cord ings of some of the char ac ter is tics of the spec trom e ter con tain ing a dig i tal MCA, such as full-peak ef ficiency, net-area ra tio of the two peaks and the sta bil ity of the peak po si tion, were carried out un der dif fer ent in put count ing rates, with dif fer ent ra dio ac tive sources. The tested MCA has shown some ex cel lent fea tures, like the sta bil ity of the peak po si tion over a long-term pe riod and flex i bil ity in the ad just ing of op ti mum mea sure ment condi tions. How ever, the per formed tests have also shown some se ri ous and un ex pected dis ad van tages of the dig i tal MCA when it op er ates un der cer tain cir cum stances, one of them hav ing to do with the au to matic tun ing of live-time cor rec tion at low-in put count ing rates. Key words: dig i tal mul ti chan nel an a lyzer, dig i tal spec trom e ter, live-time corrector, pile-up re jector Tech ni cal pa per UDC: 539.166:681.785.5

GEANT4 based Monte Carlo sim u la tions have been car ried out for the de ter mi na tion of ef ficiency and con ver sion fac tors of a gas-flow ion iza tion cham ber for beta par ti cles emit ted by 86 dif fer ent ra dio iso topes cov er ing the av er age-b en ergy range of 5.69 keV-2.061 MeV. Good agree ments were found be tween the GEANT4 pre dicted val ues and cor re spond ing ex per imen tal data, as well as with EGS4 based cal cu la tions. For the re ported set of b-emit ters, the val ues of the con ver sion fac tor have been es tab lished in the range of 0.5×10 13 -2.5×10 13 Bqcm -3 /A. The com puted xe non-to-air con ver sion fac tor ra tios have at tained the min i mum value of 0.2 in the range of 0.1-1 MeV. As the ra dius and/or vol ume of the ion cham ber increases, con ver sion fac tors ap proach a flat en ergy re sponse. These sim u la tions show a small, but sig nif i cant de pend ence of ion iza tion ef fi ciency on the type of wall ma te rial.

Many non-vol a tile im pu ri ties ac ci den tally in tro duced into the steam gen er a tor tend to con cen trate on its sur face in re stricted flow ar eas. In this way these im pu ri ties can lead to stress cor ro sion crack ing (SCC) on stressed tubes of the steam gen er a tor. Such impu ri ties can be strong al ka line or acid so lu tions. To eval u ate the ef fect of al ka line concen trated en vi ron ments on SCC of steam gen er a tor tubes, the tests were con ducted on stressed sam ples of Incoloy-800 in 10% NaOH so lu tion. To ac cel er ate the SCC process, stressed spec i mens were an od i cally polar ised in a caus tic so lu tion in an elec trochem i cal cell. The method of stress ing of Incoloy-800 tubes used in our ex per i ments was the C-ring. Us ing the cath odic zone of the potentiodynamic curves it was pos si ble to cal cu late the most im por tant elec tro chem i cal pa ram e ters: the cor ro sion cur rent, the cor ro sion rate, and the polar is ation re sis tance. We found that the value of the cor rosion po ten tial to ini ti ate the SCC microcracks was -100 mV. The tested sam ples were ex am ined us ing the metallographic method. The main ex per i men tal re sults showed that the in crease of the stress state pro moted the in crease of the SCC sus cep ti bil ity of Incoloy-800 sam ples tested un der the same con di tions, and that the length of the SCC-type microcracks in creased with the growth of the stress value. Key words: al ka line SCC, Incoloy-800, ac cel er ated tests 74 Nu clear Tech nol ogy & Ra di a tion Pro tec tion -1/2005 Sci en tific pa per

Three-dimensional (3-D) nonlinear site response analyses are conducted using finite element models of actual soil profiles from ten nuclear power plant (NPP) sites in the United States to investigate the effects of soil properties and input motions on site amplification. The modeling approach developed in this study combines several novel elements, such as 3-D analysis (including vertical motions), nonlinear inelastic behavior of soil (strain-dependent shear modulus reduction and hysteretic damping), formulation of nonreflecting boundary conditions at the base, and generation of realistic outcrop ground motions for specific sites. All these elements of the modeling approach are first validated using actual data from five earthquakes at three downhole array stations recorded in the Kiban-Kyoshin network (KiK-net), Japan. The same approach is then used to develop site models of ten NPP sites in the United States and corresponding ground motions that are spectrally matched to the site hazard spectra. Eight sets of three-component input motions are used in the study and are categorized on the basis of presence or absence of a near-field pulse in the seed ground motions used for spectral matching. It is found that all sites retain a definite site amplification function regardless of the input motion, provided that the seed motion is spectrally matched to the site hazard spectra. The magnitude of site amplification and frequencies at which they occur depend upon soil properties, particularly the shear wave velocity profile and the constitutive relationship (strain-dependent shear modulus reduction and hysteretic damping) of soil. Amplification of spectral acceleration in the vertical direction (up-down motion) is found to be just as much as, if not more than, the amplification in the horizontal direction. Peak shear strain is found to be about 20% larger for near-field motions compared to far-field motions whereas maximum horizontal site amplification for far-field motions is found to be consistently larger than that of near-field motions, even though the differences between the two remain within the scatter resulting from individual ground motions.

identifies, characterises and analyses International Organisation for Standardisation (ISO) and International Atomic Energy Agency (IAEA) normative requirements for the development and implementation of quality management systems in nuclear organisations. The applicable standards are identified and their requirements are characterised and reviewed. The correspondence and correlation between the applicable standards' requirements are presented.

The ef fect of the den sity of en vi ron men tal sam ples on the count ing ef fi ciency of Ge detec tors used in gamma-spec trom e try was stud ied. The de pend ence e ff (r) was de termined for two HPGe de tec tors (rel a tive ef fi cien cies 18% and 20%), us ing five ra dio active stan dard ref er ence ma te ri als (sil i cone res ins, ep oxy resin, milk pow der, soil) with dif fer ent ma trix den si ties (0.45-1.22 g/cm 3 ) in Marinelli beak ers (V = 500 cm 3 ). The de pend ence of ef fi ciency vs. den sity was found to be lin ear and the re gres sion pa ram eters for en er gies in the range of 60-2000 keV were de ter mined, too. The ef fect of vari ation in den sity on the count ing ef fi ciency of Ge de tec tors is dom i nant in the range of lower en er gies (60-600 keV) and de creases with en er gies in the higher en ergy range.

A pri mary-in ter ac tion based Monte Carlo al go rithm has been de vel oped for de ter mina tion of the to tal ef fi ciency of cy lin dri cal scin til la tion g-ray de tec tors. This meth od ology has been im ple mented in a Matlab based com puter pro gram BPIMC. For point iso tro pic sources at ax ial lo ca tions with re spect to the de tec tor axis, ex cel lent agreement has been found be tween the pre dic tions of the BPIMC code with the cor respond ing re sults ob tained by us ing hy brid Monte Carlo as well as by ex per i men tal mea sure ments over a wide range of g-ray en ergy val ues. For off-axis lo cated point sources, the com par i son of the BPIMC pre dic tions with the cor re spond ing re sults obtained by di rect cal cu la tions as well as by con ven tional Monte Carlo schemes shows good agree ment val i dat ing the pro posed al go rithm. Us ing the BPIMC pro gram, the en ergy de pend ent de tec tor ef fi ciency has been found to ap proach an as ymp totic pro file by in creas ing ei ther thick ness or di am e ter of scintillator while keep ing the other fixed. The vari a tion of en ergy de pend ent to tal ef ficiency of a 3" ´ 3" NaI(Tl) scintillator with ax ial dis tance has been stud ied us ing the BPIMC code. About two or ders of mag ni tude change in de tec tor ef fi ciency has been ob served for zero to 50 cm vari a tion in the ax ial dis tance. For small val ues of ax ial sep ara tion, a sim i lar large vari a tion has also been ob served in to tal ef fi ciency for 137 Cs as well as for 60 Co sources by in creas ing the ax ial-off set from zero to 50 cm.

... Fast multiple-path model to calculate radionuclide release from the near field of a repository. Auteur(s) / Author(s). ROMERO L. ; MORENO L. ; NERETNIEKS I. ; Affiliation(s) du ou des auteurs / Author(s) Affiliation(s). Royal inst. technology, dep. ... Flujo agua. ; Transporte. ...

This paper provides a comparison between the Best Estimate plus Uncertainty methodology with the Conservative Bounding methodology for Design Basis Accident analysis. Calculations have been performed with TRACE (for thermalhydraulic system calculations) and PARCS (for neutron-kinetics modeling) under SNAP platform. DAKOTA is used under the SNAP interface for uncertainty and sensitivity analysis. A simplified 3D neutronics model of the ASCO II NPP is used as core kinetic model. The thermal-hydraulic model is a 1D representation of the primary and secondary systems except for the vessel that is represented by a 3D VESSEL component. The design basis transient selected for the comparison is a Main Steam Line Break (MSLB) in a PWR. This transient is characterized by space-time effects and requires coupled 3D kinetics and thermal-hydraulics modeling, especially for the re-criticality scenario. The comparison methodology is as follows. Once the models are created, a Best Estimate Base Case Calculation (BEBCC) is performed. The model is modified by selecting the most important parameters and assigning conservative values to them in order to obtain a Conservative Calculation. Several parameters are modified in this conservative way. These parameters are then perturbed in Best Estimate Plus Uncertainties (BEPU) calculations. At the end, a comparison is made between results obtained in the Conservative Calculation and the BEPU methodology respectively. As a general conclusion the BEPU method has been successfully illustrated in coupled 3D kinetics and thermal-hydraulics system. Also the study it is an effective test for the adequacy of nodalizations for the utilized codes both neutronic and thermal-hydraulic. BEPU methodology gives more margins, which allow for higher operational flexibility of the plant. Results of BEPU methodology help improve plant economics while meeting the safety standards. As a conclusion, the BEPU methodology is been successfully tested in NK-TH calculations. Narrow margins between upper and lower BEPU case are consequence of few perturbed parameters chosen and the transient boundary conditions.

La tesis busca analizar el desarrollo nuclear de Argentina y México en el periodo comprendido entre 1945 y 1991, intentando aislar los factores que explican que, partiendo de potencialidades similares, ambos países lograran al cabo de 40 años, resultados muy diferentes en los avances de sus respectivos entramados nucleares.

Three sets of data cov er ing the 2004-2007 pe riod are ex am ined: two be ryl lium-7 series and ozone mea sured in ground level air. The mea sur ing sites are at three dif fer ent lo ca tions in Bel grade, Ser bia. The tem po ral evo lu tion of be ryl lium-7 and ozone is presented, as well as their mu tual cor re la tions. Be ryl lium-7 data for Bel grade agree well with the re sults for other lo ca tions in the re gion. The cor re la tion be tween two be ryllium-7 data sets is 0.57. The re sults for ozone in di cate that Bel grade is not a com mon con ti nen tal site, as the max i mum in ozone dis tri bu tion is reached in spring time. The over all cor re la tion be tween be ryl lium-7 and ozone is good, but var ies over dif fer ent sea sons. A large cor re la tion (0.67) is noted be tween be ryl lium-7 mea sured at the site in Vin~a, Ser bia, and the monthly max i mum ozone in au tumn. An anal y sis which assumes the trans port of air masses from the strato sphere, along which the only pro cess chang ing the air mass com po si tion is ra dio ac tive de cay of be ryl lium-7, does not conclu sively con firm the high cor re la tion be tween be ryl lium-7 and ozone in au tumn. Key words: ground level air, be ryl lium-7, ozone, strato sphere-tro po sphere ex change Nu clear Tech nol ogy & Ra di a tion Protection Sci en tific pa per UDC: 546.45+546.214:614.71

This re p ro d u c tio n was made fro m a co p y o f a d o c u m e n t sent to us fo r m ic ro film in g. W hile the m ost advanced te ch no lo gy has been used to photog ra ph and reproduce this d o c u m e n t, the q u a lity o f the re p ro d u c tio n is heavily dependent upo n the q u a lity o f the m aterial su b m itte d. The fo llo w in g e xp la n a tio n o f techniques is provided to help c la rify m arkings o r n o ta tio n s w h ic h may appear on this re p ro d u c tio n. ACKNOWLEDGMENTS I wish to gratefully acknowledge the encouragement and guidance given to me by my advisor, Professor Don W. Miller. Also, the assistance and continual support throughout much of the experiments by Mr. Joseph W. Talnagi and Mr. Steven Arndt have been greatly appreciated. I am very grateful to Mr. Edward Ray for LINAC experiments, Mr. Cecil L. Rhodes for equipment calibration and advice, and the staff of the Nuclear Reactor Laboratory for their time in OSU reactor operation. In addition, I would like to thank the Nuclear Regulatory Commission of the United States for funding this project (Grant No. NRC-G-04-81-022). Finally, I wish to express my deep appreciation to Patricia Elzey,

The fluoride-salt-cooled high-temperature reactor and some proposed fusion reactors use clean fluoride salts as reactor coolants that have melting points above 450°C and generate tritium. Tritium diffuses through most hot metals, thus methods to capture tritium and prevent its release to the environment are required. Molten salt reactors (MSRs) use fluoride or chloride salts with high melting points where the fuel is dissolved in the coolant. MSR systems produce volatile fission products (Xe, Kr, etc.) and some produce significant tritium. We examine the use of heat exchangers with multiple heat pipes for salt-cooled fission and fusion systems that serve four functions: (1) transfer heat from primary coolant to power cycle, secondary loop, or environment; (2) provide the safety function of a secondary loop by isolating the reactor salt coolant from the high-pressure power cycle; (3) stop heat transfer if the reactor coolant approaches its freezing point to prevent blockage of the primary loop; and (4) block tritium escape to the environment with recovery of the tritium. Each of these capabilities in some form has been demonstrated in a heat pipe system, but not all the functions have been demonstrated in a single system because there has been no need for all of these capabilities in a single system. We review the status of heat pipe technology and the limits of heat pipe technology as the starting points for decisions on the development of such heat pipe systems.

Soviet and East European documents provide significant revelations about the interactions of North Korea and its allies. First, they show Pyongyang's longstanding interest in obtaining nuclear technology and probably nuclear weapons. Second, they reveal that North Korea's leadership consistently evaded commitments to allies on nuclear matters—particularly constraints on its nuclear ambitions or even the provision of information. Third, North Korea's words and deeds evoked substantial concerns in Moscow and other communist capitals that Pyongyang, if it obtained nuclear weapons, might use them to blackmail its partners or risk provoking a nuclear war. When aid from the Union of Soviet Socialist Republics was not forthcoming, the Democratic People's Republic of Korea sought to bypass Moscow and obtain assistance from the Kremlin's East European clients and, when that proved fruitless, from Pakistan. The absence of international support reinforced the logic of self-...

Este capítulo tiene como objetivo hacer un breve recorrido por las
trayectorias nucleares de los cinco países latinoamericanos con los
programas atómicos más avanzados de la región, haciendo hincapié
en el análisis de su evolución a lo largo de los primeros 15 años
del siglo xxi, y reflexionando sobre el impacto de tales proyectos
en los relacionamientos intra y extrarregionales para estos países.

1 Rus sian Re search Cen tre "Kurchatov In sti tute", Mos cow, Rus sia 2 In sti tute of Solid State Chem is try of the Ural De part ment of Rus sian Acad emy of Sci ences, Ekaterinburg, Rus sia 3 In sti tute of Metal Phys ics of the Ural Branch of the Rus sian Acad emy of Sci ences, Ekaterinburg, Rus sia Sci en tific pa per

Thermoluminescent MCP-N de tec tors based on LiF:Mg,Cu,P are by about 2 or ders of mag ni tude more sen si tive than TLD-100 de tec tors based on con ven tional LiF:Mg,Ti, which makes it pos si ble to use them in short-term mon i tor ing of ion is ing ra di a tion in the en vi ron ment (e. g., over a two-week pe riod, rather than over 3-12 months). We de scribe the prop er ties of MCP-N de tec tors and meth ods of their ap pli ca tion in en vi ron men tal mon i tor ing. The sys tem was tested in short and long-term ex po sure pe ri ods at 100 sites around Krakow re gion. MCP-N de tec tors were then ap plied to mea sure vari a tion of ra dia tion dose rate at four se lected vil lages in Ser bia, where de pleted ura nium am mu ni tion was de ployed in 1999. To gether with short-term thermoluminescent do sim e try, in situ mea sure ments us ing pro por tional coun ters were per formed in or der to as sess the range of vari a tion of nat u ral ra di a tion back ground in these vil lages. The mean ter res trial kerma dose rate in these vil lages was found to vary be tween 85 and 116 nGyh -1 and the av er age am bi ent dose equiv a lent rate H * (10) de ter mined by thermoluminescent de tec tors and by pro por tional coun ter mea sure ments was 160 nSvh -1 . These val ues of nat u ral ra di a tion back ground dose rates can be ap plied as ref er ence lev els for field mea sure ments around other sites where de pleted ura nium am mu ni tion was de ployed.

Experiments were performed in a scaled annular cavity design, to investigate melt dispersal from the reactor pit when the reactor pressure vessel lower head fails at low system pressure of less than 2 MPa. In the part of the experimental program presented in this paper, the fluid dynamics of the dispersion process was studied using model fluids, water or bismuth alloy instead of corium, and nitrogen or helium instead of steam. The effects of different breach sizes and locations, and different failure pressures on the dispersion were studied, specifically by testing central holes, lateral holes, horizontal rips, and complete ripping of the bottom head. The experiments have shown, that lateral failures lead to smaller melt dispersal out of the reactor pit than failures in the central part of the lower head. With holes at the base of the bottom head, the most important parameters governing the dispersion of melt are the hole size and the burst pressure. The fraction dispersed into the ...

Incorporating full three-dimensional models of the reactor core into system transient codes allows for a "best-estimate" calculation of interactions between the core behavior and plant dynamics. Considerable efforts have been made in various countries and organizations on the development of coupled thermal-hydraulic and neutronics codes. Appropriate benchmarks have been developed in international co-operation led by NEA/OECD that permits testing the neutronics/thermal-hydraulics coupling, and verifying the capability of the coupled codes to analyze complex transients with coupled core-plant interactions. Three such benchmarks are presented in this paper -the OECD/NRC PWR MSLB benchmark, the OECD/NRC BWR TT benchmark, and the OECD/DOE/CEA V1000CT benchmark. In order to meet the objectives of the validation of best-estimate coupled codes a systematic approach has been introduced to evaluate the analyzed transients employing a multi-level methodology. Since these benchmarks are based on both code to code and code to data comparisons further guidance for presenting and evaluating results has been developed. During the course of the benchmark activities a professional community has been established, which allowed carrying out indepth discussions of different aspects considered in the validation process of the coupled codes. This positive output has certainly advanced the state-of the art in the area of coupling research.