Lithium ion-selective membrane for the determination of the lithium concentration in a fluid of the primary coolant circuit of a pressurized water reactor of a nuclear power plant.

A lithium ion-selective membrane for the detn. of the lithium concn. in a fluid of the primary coolant circuit of a pressurized water reactor of a nuclear power plant consists of a polymeric support, a plasticizer, a conducting compd., as well as a lithium-specific ionophore 6,6-dibenzyl-14-crown-4. The membrane contains 0.5-3 wt.% of the ionophore. The polymeric support is made of PVC, and the plasticizer can be o-nitrophenyloctylether or bis 1-butylpentyl adipate. The conductive compd. is potassium tetrakis(4-chlorophenyl)borate. The membrane is produced by completely dissolving the support polymer, the plasticizer, the conductive compd., and the ionophore in THF under magnetic agitation and at ambient temp., and evapg. the solvent at ambient temp. for crystn. to form the membrane. The membrane is used in a lithium-selective electrode

Study of various chemical species behaviour for contamination risk

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lnfluence of major PWR radiochemical pollutants on dose rates and dosimetry - lmportance of efficiency of retention techniques

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Corrosion product transfer in French PWRs during shutdown

International audiencePhysicochemical conditions significantly vary during cold shutdown in French PWRs: power and temperature decrease, chemical conditions are modified (pH decrease and change from reducing to oxidizing conditions). These changes involve corrosion product releases in the primary water (dissolving and crud bursts) which can be seen by a considerable corrosion product increase, from 2 to 3 orders of magnitude, in the activity concentrations (about a hundred GBq/t of 58 Co, about one GBq/t of 60 Co…) and in the chemical species quantity (several kilograms of nickel, several hundred grams of chromium…). The 58 Co peak activities which are lower than the French PWR average are generally due to delayed or incomplete oxygenations or unscheduled shutdowns with oxygenation during operating cycles. An unscheduled shutdown with oxygenation in the last six months of an operating cycle must reduce the 58 Co activity peak during refueling shutdown, more especially as the unscheduled shutdown occurs near the end of the cycle. Thus, when the shutdown happens in the three months prior to the end of the cycle, it is very likely that the 58 Co peak during the refueling shutdown will be two times lower than the expected peak. The large quantity of corrosion products released during shutdown mainly come from the dissolution of the incore deposits due to primary system oxygenation, in particular the dissolution of nickel metal or nickel oxide, leading to the dissolution of the 58 Co derived from the nickel sites in the crud. Thus, the total 58 Co activity released during oxygenation is equal to, or even higher than, the out-of-core total surface activity. Therefore, the cold shutdown procedure must prevent the transfer of this considerable activity from the in-core to the out-ofcore surfaces. Deposited activity measurements carried out in French PWR primary circuits have never shown any visible contamination reduction during cold shutdown. On the contrary, recontamination can occur because of a temperature plateau or an oxygenation at a temperature over 80°C. That is the reason why: • Primary circuit oxygenation at 80°C, • Rapid temperature decrease and • Improvements on primary fluid purification, during cold shutdowns, have, up to this day, been the main points in the EDF strategy to reach the required dosimetric goals (ALARA), all the while optimizing unit outage schedules (availability). This paper thus proposes a description of corrosion product behaviour during French PWR shutdowns in order to optimise cold shutdown procedures

Chromosomal localization of the human histamine H1-receptor gene

International audienceWe have assigned the human histamine H1-receptor gene to chromosome 3 by Southern blot analysis of a chromosome mapping panel constructed from human-hamster somatic cell hybrids. This assignment was confirmed by in situ hybridization on metaphase chromosomes and involved bands 3p14-p21

Malignant Myeloblastic Transformation of Murine Long-Term Bone Marrow Cultures by F-MuLV: In Vitro Reproduction of a Long-Term Leukemogenesis, and Investigation of Preleukemic Events.

International audienceA Friend helper virus I−5(F‐MuLV) which induces my‐eloblastic leukemias in mice after a latency of several months, was used to infect long‐term bone marrow cultures. From 48 to 71 weeks after in vitro infection, 4/14 cultures gave rise to transplantable malignant myeloblas‐tic cells. These cells were shown to genuinely result from an in vitro transformation of virus‐infected normal bone marrow cells. The in vitro transformation reproduced the course of the in vivo disease. It provided unique material for in vitro investigation of the preleukemic stages of long‐term leukemogenesis. Successive cellular events were: (I) freezing of the normal myelomonocytic differentiation process; (2) change from factor‐dependent to an autonomous growth; (3) acquisition of in vivo tumorigenicity

Malignant Myeloblastic Transformation of Murine Long-Term Bone Marrow Cultures by F-MuLV: In Vitro Reproduction of a Long-Term Leukemogenesis, and Investigation of Preleukemic Events.

International audienceA Friend helper virus I−5(F‐MuLV) which induces my‐eloblastic leukemias in mice after a latency of several months, was used to infect long‐term bone marrow cultures. From 48 to 71 weeks after in vitro infection, 4/14 cultures gave rise to transplantable malignant myeloblas‐tic cells. These cells were shown to genuinely result from an in vitro transformation of virus‐infected normal bone marrow cells. The in vitro transformation reproduced the course of the in vivo disease. It provided unique material for in vitro investigation of the preleukemic stages of long‐term leukemogenesis. Successive cellular events were: (I) freezing of the normal myelomonocytic differentiation process; (2) change from factor‐dependent to an autonomous growth; (3) acquisition of in vivo tumorigenicity

Design performances and chemistry program supporting the FA3/UK-EPR

EPRTM reactor accounts with an evolutionary design that provides the appropriate features to ensure the safety implementation of different chemistry and radiochemistry options. ALARP considerations have been taken into account by EDF-AREVA for making decisions relating to the activity management in the primary circuit of FLAMANVILLE 3-EPRTM and UK-EPRTM reactors. The water chemistry and radiochemistry concept implemented in FA3-EPRTM and UK-EPRTM reactors is the result of an exhaustive selection process based on the balance between the theoretical developments, the laboratory tests and the NPP experience concerning the diverse areas associated with: • The source term identification and characterization: The understanding of the origin and behavior of fission products/actinides, corrosion products and activation products constitutes the essential support for the selection of suitable parameters and criteria to monitor the system integrity, the tramp-uranium and radiation build-up and the discharges to the environment. • The source term quantification: The balance between the baseline data from PWR forerunner reactors and the assessments performed by modelling constitutes the major demonstration of the source term accuracy. This approach ensures that activity risks are understood and can be managed with the EPRTM design options. The EPRTM design options evaluation: The sensitivity analysis results show the influence of the fuel management, the material choice and the chemistry conditioning on several domains such as the activity coolant and the fuel/ex-core crud management. EDF-AREVA demonstrates by means of this process that the design, sizing and chemistry conditioning of EPRTM reactor primary circuit are adapted to guarantee the correct activity management. The methodology developed, based on qualitative and quantitative assessments, intends to propose to the Nuclear Industry several alternatives for evaluating and/or improving the compliance with requirements associated with safety, material integrity, radioprotection and environment

ERRα coordinates actin and focal adhesion dynamics

International audienceCell migration depends on the dynamic organisation of the actin cytoskeleton and assembly and disassembly of focal adhesions (FAs). However, the precise mechanisms coordinating these processes remain poorly understood. We previously identified the oestrogen-related receptor α (ERRα) as a major regulator of cell migration. Here, we show that loss of ERRα leads to abnormal accumulation of actin filaments that is associated with an increased level of inactive form of the actin-depolymerising factor cofilin. We further show that ERRα depletion decreases cell adhesion and results in defective FA formation and turnover. Interestingly, specific inhibition of the RhoA-ROCK-LIMK-cofilin pathway rescues the actin polymerisation defects resulting from ERRα silencing, but not cell adhesion. Instead, we found that MAP4K4 is a direct target of ERRα and down-regulation of its activity rescues cell adhesion and FA formation in the ERRα-depleted cells. Altogether, our results highlight a crucial role of ERRα in coordinating the dynamic of actin network and FAs through the independent regulation of the RhoA and MAP4K4 pathways