Authors:G Marmureanu, M Androne, M Radulian, E Popescu, C O Cioflan, A O Plăcintă, I A Moldovan and V Serban
Attenuation specific from Vrancea intermediate-depth focus toward SE is revised at length in order to re-evaluate the seismic hazard at the nuclear power plant (NPP) Cernavoda. To this aim, we took into consideration all the strong motion data available for the region and test a large range of relationship types. Since the instrumental data are limited as magnitude and depth intervals, the extrapolation based on the attenuation laws deduced from these data to great magnitudes is very instable and must be carefully considered. The extrapolation outside the characteristic domain of the available database leads to large deviations, especially at large magnitudes and for the relations which contain the depth as independent parameter.
Authors:I. Svetlik, M. Fejgl, K. Turek, V. Michalek and L. Tomaskova
The Czech Republic has two nuclear power plants (NPPs) equipped with light water pressurized reactors (LWPR). Annual sampling
of biota for 14C activity monitoring by Nuclear Physics Institute in cooperation with the National Institute of Radiation Protection started
in 2002. We present the results of biota monitoring covering two sampling periods 2002–2005 and 2007–2008. The considerable
problem in the case of biota sampling for monitoring purpose is given by a relatively short period of biota accumulation for
prevailing types of biota samples (leaves of deciduous trees or agricultural plants), which usually lasts from several weeks
to 2 months. The short period of sample accumulation can also be partly overlapped by a service period of reactor outage in
a given NPP. On the base of our several years’ experiences we have changed a type of the sampled material to reduce variations
of observed activities and to precise reference levels in the exposed and reference sites.
Authors:R. Chobola, R. Chobola, P. Mell, P. Mell, L. Daróczi, L. Daróczi, A. Vincze and A. Vincze
A relatively simple chemical separation procedure has been developed for the simultaneous determination of89Sr and 9 0Sractivities in water samples and on aerosol-filters of the Nuclear Power Plant (NPP) Paks origin. The procedure combines
the cation-exchange chromatographic (Dowex 50 WX 8 resin) and solid phase extraction (EIChroM Sr.SpecÔ, DC18C6 crown ether)
steps. The beta-radiation of radionuclides can be measured directly after the chemical separation by LSC. The activities of89Sr,90Sr and90Y are calculated from an over determined set of equations using a method of constrained optimization technique. The equations
are based on LSC measurements performed in three counting windows plus the90Sr-90Y decay law. The chemical yield of strontium is determined by ICP-AES. The lowest limits of detectable activity, for the measurement
time of 600 minutes, are 30 mBq/sample and 18 mBq/sample for89Sr and90Sr, respectively.
Authors:P. Rajec, L. Matel, L. Drahošová and V. Nemčovič
14C releases in the stack air of the NPPs V1 and V2, Jaslovske Bohunice was determined during the year 2004–2010. Radioactivity
concentration of 14C in the stack air was determined in the forms of inorganic 14CO2 and 14CnHm. The annual average activity concentration in the stacks air samples varies between 12 and 121 Bq m−3. NPP V1, starting with 45 Bq m−3 in 2005 is decreasing due to the shutting down of the reactors (the first reactor was shut down in December 2006 and the
second reactor in December 2008). The average value of radioactivity concentration for power unit V2 was 32 Bq m−3 in 2004 and reached the value of 102 Bq m−3 in the first-quarter of the 2010. The average normalized yearly discharge rates were between 0.39 and 0.64 TBq GWe−1 year−1 (2005–2008), NPP V1 and 0.19–0.61 TBq GWe−1 year−1 (2004–first-quarter 2010) for NPP V2, Jaslovske Bohunice. Most of the discharged 14C is in a hydrocarbon form, (95% for Jaslovske Bohunice NPP V2), but the CO2 fraction may reach 37% in the air stack for Jaslovske Bohunice V1.
The 18 km long banks of the Bohunice NPP waste water recipient are contaminated by137Cs as a result of two accidents on the CO2 cooled NPP-A1 unit in 1976 and 1977. Contamination acceptance limits 6 or 8 Bq137Cs/g of soil, depending on contaminated area size, were derived on the basis of developed principles, and approved by the authorities. Removing and safe burial of 1100 m3 of contaminated soil from steep area and 15 cm thick clean soil covering on about 1 ha of flat area of the contaminated banks is planned in frame of the re-considered restoration project implementation in 1995/96.
Authors:K. Radó, Z. Németh, K. Varga, J. Schunk and F. Kőrösi
the period of 1993-2001 chemical decontaminations of 24 SGs in the units 1-3 of
the Paks NPP were carried out by a non-regenerative version of AP-CITROX
technology, even in two or three consecutive cycles. A comprehensive
investigation of the above decontamination method have revealed that the
fundamental issues of analytical chemistry and corrosion science were not taken
into consideration during the elaboration of AP-CITROX procedure. Therefore,
the non-regenerative version of the technology utilized at Paks NPP can be
considered to be not an adequate method for the chemical decontamination of any
reactor equipments having large steel surfaces (e.g., SGs). As a consequence of
the lack of the appropriate decontamination method, initiation of a R&D project
focused on the elaboration of the required technology should not be postponed.
In this paper, we present a brief overview on the fundamental issues of the
technology development. Selected findings obtained in our laboratory on
the field of the improvement of the AP-CITROX technology are also reviewed in
order to demonstrate the crucial role of some selection criteria.
A simple, sensitive and reliable method was developed for the determintion of hydrazine in technological waters of NPPs. A pulverized mixture of oxalic acid and p-dimethylaminobenzal dehyde is added to a sample. As low as 1.5 g.dm–3 hydrazine can be determined. The method is dependent of the sample temperature. The agent is stable, readily soluble in water, and not hygroscopic.
A repülőgép-becsapódáshoz tartozó extrém terhek valószínűsége átlagos építmények esetén elhanyagolható, így az általános tervezési előírások, szabványok ezeket nem tartalmazzák. Kiemelt létesítmények, például atomerőművek esetében azonban a lehetséges következmények súlyossága miatt mindenképpen foglalkoznunk kell ütközések hatásaival, az előírt vizsgálatok a tervezési alapban is megjelennek. Cikkünk nagy merevségű szerkezetbe történő repülőgép-ütközés hatásait tárgyalja építőmérnöki szempontból. Az atomerőmű konténmentjének, a hermetikus teret határoló szerkezetnek a falai 1–1,5 m vastagságú vasbeton anyagú, sűrűn, több rétegben vasalt falak, így a vasbeton anyag viselkedése jelentős mértékben meghatározza az ütközés következményeit. Röviden összefoglaljuk a beton és a betonacél viselkedésének jellemzőit magas hőmérséklettel járó, ütközés jellegű terhek esetén. Ezen felül bemutatjuk az ütközés globális (teljes szerkezetet érintő) és lokális (az ütközési zónában lejátszódó, az állékonyságot nem veszélyeztető) hatásait. Kitérünk a hatások lehetséges modellezésére, a napjainkban leginkább elterjedt számítási, vizsgálati módszerekre.
Authors:A. Krivokhatsky, Yu. Dubasov, E. Smirnova, N. Skovorodkin, V. Savonenkov, B. Alexandrov and E. Lebedev
Actinide elements concentrations in the products of near release from CNPP accident were estimated. The data on uranium,237Np,241Am and plutonium and curium isotopes content in fuel particles are given. Sums of -emitting radionuclides and plutonium isotopes in reactor graphite particles and of uranium,242Cm,239+240Pu isotopes in the soil and aerosol samples were also determined. By 1989 soil and dust contamination in near release of the accident is due to long-lived -emitting plutonium isotopes.