新疆伊犁盆地南缘512铀矿床镭－氡放射性平衡规律初探

对可供地浸法开采的５１２铀矿床镭－氡放射性平衡规律进行初步研究表明，在对该矿床钻孔施工过程中，由于泥浆压力的存在，使镭－氡放射性平衡遭到破坏，严重地降低了伽玛测井的伽玛照射量率，使按伽玛测并确定的储量计算参数不准确。为此，作者对这一平衡破坏规律进行了初步研究，确定了储量计算参数的镭一氡平衡破坏修正值，既消除了伽玛测井的影响因素，又增加了２０％的远景储量。建议在今后对该矿床进一步工作时，对该平衡破坏规律采用岩芯取样为主，同时辅以适量的专门物探参数观测孔进行验证的研究方案。     

乌库尔齐铀矿床镭-氡放射性平衡系数计算及讨论

从分析镭-氡放射性平衡破坏的原因出发,以新疆乌库尔齐可地浸砂岩型铀矿床为例,探讨了镭-氡放射性平衡系数的计算方法,并对不同的计算方法进行了讨论。该系数的取得,为乌库尔齐铀矿床测井数据的修正、矿体边界的划分、铀矿资源量的计算提供了科学依据。     

乌库尔齐铀矿床镭-氡放射性平衡系数计算及讨论

从分析镭-氡放射性平衡破坏的原因出发,以新疆乌库尔齐可地浸砂岩型铀矿床为例,探讨了镭-氡放射性平衡系数的计算方法,并对不同的计算方法进行了讨论。该系数的取得,为乌库尔齐铀矿床测井数据的修正、矿体边界的划分、铀矿资源量的计算提供了科学依据。     

γ能谱法测量铀矿石样品镭-氡平衡系数的初步探索

以测定铀矿石镭-氡平衡系数为目的,提出了对铀矿石样本进行γ能谱测量,根据铀系的衰变平衡规律,利用γ能谱中的特征峰计数计算镭、氡含量。推导了镭-氡平衡系数的计算公式,重点对相关参数进行了探讨。该方法简单、快速,进一步完善后可应用于钻孔岩心样本的现场分析。     

地浸砂岩型铀矿镭—氡放射性平衡对伽玛测井解释结果的影响研究

地浸砂岩型铀矿钻探勘查过程中,由于钻孔内＂压氡现象＂的存在,使钻孔内铀矿层的镭—氡含量出现暂时的不平衡现象,往往会造成伽玛测井解释结果系统偏低,影响了铀矿资源量评价的准确程度。因此在地浸砂岩型铀矿勘查过程中,必须设计一定数量的物探参数孔,及时开展镭—氡放射性平衡系数的研究和评价。     

我国铀矿床放射性平衡系数的变化特征

放射性平衡系数是表征铀矿床物理特性的重要参数。γ强度测量法实质上是探测铀的衰变产物氡子体的γ强度,通过它间接测铀。这只有当铀镭处于放射平衡状态时才是正确的。若铀镭的平铀状态遭到破坏,用γ法测量不加修正就不能准确地确定铀含量。因此,铀镭平衡系数及其变化规律的研究对于铀矿普查和勘探工作都有着重要的意义。     

应用遗传算法对镭氡平衡曲线的研究

本文通过分析常规计算镭氡平衡系数的误差因素及钻孔中镭氡平衡的动力学过程,建立了求解镭氡平衡系数的数学模型.应用遗传算法来设计、求解相应模型的待定参数,编写相关程序段,进行迭代求解.计算出了单矿段及铀矿床总镭氡平衡系数.     

铀矿石中铀镭平衡系数与铀含量关系探讨

铀镭平衡系数是描述铀系中铀镭平衡状态的一个参数。它不仅关系到铀矿床储量计算的可靠性,而且关系到寻找铀矿床的某些找矿方法的应用效果。因此有必要对它作进一步的探讨。铀镭平衡系数可由下式计算:     

空气中氡浓度的预测

氡是一种放射性惰性气体,它与肺癌的关系已引起人们的高度重视,世界上许多国家都开展了环境氡的研究工作;氡的母体元素铀、镭在地质环境中的分布与空气中的氡浓度水平有密切关系,通过研究地质环境中铀、镭的分布资料,就能快速定性地评价空气中氡浓度水平.     

氡的迁移富集及对环境的影响

氡（Ｒｎ）是镭（Ｒａ）放射性衰变的中间产物,属于放射性惰性气体,经常溶解于水中或释放在空气中,过量则对人体健康会造成危害。地下水富集氡的程度主要取决于岩石中镭的含量和岩石的射气作用,铀矿区和含放射性元素偏高的岩石分布区,地下水氡浓度较高。地下水的运动是氡运移到地表的主要途径,空气的氡主要来源于植物的蒸发和含氡地下水的释放作用;在使用氡浓度高地下水的室内,空气的氡浓度与氡源距离和空气对流率呈负相关,     

关于油气勘查与开采中氡和镭测量的应用问题

本文介绍了放射性同位素氡和镭测量在油气勘查与开采中的某些应用和相应的机理。     

Evaluation of the 210Po method at the Midwest uranium deposit,Northern Saskatchewan,Canada

Vertical profiles of ²¹⁰Po in soils near the Midwest uranium deposit and an associated surficial radioactive sandstone boulder train in northern Saskatchewan show a high ²¹⁰Po background in air-dried forest litter (24 pCi/g) and Ah horizon soil (11 pCi/g) relative to lower soil horizons (<1 pCi/g). These high levels mask the ²¹⁰Po signal from the radioactive boulders in the near-surface soil horizons. Only in the Bf and C horizons can the existence of the radioactive boulders be inferred from ²¹⁰Po determinations. For comparative purposes profiles for ²²⁶Ra, U, Ni, and other trace elements are also presented.Escape of most of the Rn from near surface soils into the atmosphere, homogenization and decay of Rn, and precipitation of decay products back onto surface soils satisfactorily explain the field observations discussed here.Compared to the highly anomalous ²²²Rn signal in soil gases over this boulder train the ²¹⁰Po contrast is very weak and is of little use for prospecting for this type of boulder train. The relatively high ²¹⁰Po background in surficial materials relative to lower soil horizons dictates that great care be taken with the ²¹⁰Po method; the deepest possible horizons should be sampled.     

Relationships between radium and radon occurrence and hydrochemistry in fresh groundwater from fractured crystalline rocks, North Carolina (USA)

Naturally-occurring radionuclides (uranium, radium, and radon), major dissolved constituents, and trace elements were investigated in fresh groundwater in 117 wells in fractured crystalline rocks from the Piedmont region (North Carolina, USA). Chemical variations show a general transition between two water types: (1) slightly acidic (pH 5.0–6.0), oxic, low-total dissolved solids (TDS) waters, and (2) near neutral, oxic to anoxic, higher-TDS waters. The uranium, radium, and radon levels in groundwater associated with granite (Rolesville Granite) are systematically higher than other rock types (gneiss, metasedimentary, and metavolcanic rocks). Water chemistry plays a secondary role on radium and radon distributions as the ²²²Rn/²²⁶Ra activity ratio is correlated with redox-sensitive solutes such as dissolved oxygen and Mn concentrations, as well as overall dissolved solids content including major divalent cations and Ba. Since ²²⁴Ra/²²⁸Ra activity ratios in groundwater are close to 1, we suggest that mobilization of Ra and Rn is controlled by alpha recoil processes from parent nuclides on fracture surfaces, ruling out Ra sources from mineral dissolution or significant long-distance Ra transport. Alpha recoil is balanced by Ra adsorption that is influenced by redox conditions and/or ion concentrations, resulting in an approximately one order of magnitude decrease (~ 20,000 to ~ 2000) in the apparent Ra distribution coefficient between oxygen-saturated and anoxic conditions and also across the range of dissolved ion concentrations (up to ~ 7 mM). Thus, the U and Th content of rocks is the primary control on observed Ra and Rn activities in groundwater in fractured crystalline rocks, and in addition, linked dissolved solids concentrations and redox conditions impart a secondary control.     

基于克里格法刻画砂岩型铀矿U、Ra和U-Ra平衡系数垂向分布规律——以二连盆地芒来铀矿床为例

砂岩型铀矿是绿色经济可采的重要能源矿种,目前是世界上重要的铀矿勘探类型之一。二连盆地芒来铀矿床、鄂尔多斯盆地纳岭沟铀矿床铀矿体多呈板状产出,板状铀矿体成因备受关注。为研究砂岩型铀矿内部U、Ra和铀镭平衡系数（Kp）分布的垂向分布规律,本文以二连盆地芒来铀矿床为例,采用具有网格精度高优点的克里格插值法研究U、Ra和Kp垂向分布规律,分别利用放射性样品分析数据和定量伽马测井五点式反褶积法反演U含量数据,通过克里格法精细刻画砂岩型矿体中U、Ra和Kp分布的垂向分布规律。研究发现,该矿床板状矿体内部具有卷状的特征,Kp分布形态可以用来判断含氧含铀水的运移方向以及氧化强弱。该方法对研究铀矿体形态、铀矿成矿规律和后续地浸开采具有重要意义。     

Ra and Rn isotopes as natural tracers of submarine groundwater discharge in the patagonian coastal zone (Argentina): an initial assessment

Submarine groundwater discharge (SGD) is herein recognized as a significant pathway of material transport from land to the coastal SW Atlantic Ocean and thus, it can be a relevant factor affecting the marine biogeochemical cycles in the region. This paper focuses on the initial measurements of ²²⁶Ra, ²²⁸Ra and ²²²Rn made in Patagonia’s coastal zone of Chubut and Santa Cruz provinces (42°S–48°S, Argentina). ²²⁶Ra activity ranged from 2.9 to 73.5 dpm 100 L^?1, and ²²⁸Ra activity ranged from 11.9 to 311.0 dpm 100 L^?1 in groundwater wells. The radium activities found in Patagonia’s marine coastal regions and adjacent shelf indicate significant enrichment throughout the coastal waters. Groundwater samples presented the largest ²²²Rn activity and ranged from 2.66 to 1083 dpm L^?1. Conversely, in the coastal marine environment, the ²²²Rn activity ranged from 1.03 to 6.23 dpm L^?1. The Patagonian coastal aquifer showed a larger enrichment in ²²⁸Ra than in ²²⁶Ra, which is a typical feature for sites where SGD is dominant, probably playing a significant role in the biogeochemistry of these coastal waters.     

706矿点钻孔放射性水异常的揭露评价

本文总结了706矿点水中放射性元素的富集、迁移、分布特点及其与水的化学成分的关系,作者评价了该区放射性水异常的铀成矿远景,并进一步指导了水化学找矿工作。另外,根据该矿点的水文地质条件和氡的迁移规律,定量预测了盲矿体赋存的空间位置。     

两种方法测定岩矿石密度的对比研究

可地浸砂岩铀矿储量计算中所需的岩矿石密度,目前用取样测定法--石蜡法获得,而放射性物探方法之一γ-γ散射测井作为参考.笔者在新疆吐哈盆地某铀矿床密度测定中,对2种方法测定的密度结果进行了资料整理、研究对比,认为后者完全可以取代前者,提供准确的岩矿石密度值.     

Distribution of radon sources and effects on radon emanation in granitic soil at Ben Lomond,California

The abundance and distribution of radioelements on bulk and microscopic scales were investigated in residual granitic-derived soil at a facility for investigating the movement of radon into structures. In bulk soil samples, Ra concentrations range from 0.6 to 1.3 pCi/g, and variations in Ra, Th, and K appear to be controlled mainly by heterogeneities inherited from the parent granitic rock, which contains abundant dikes and inclusions. U in soil and parent rock is concentrated in primary minerals (mainly zircon and sphene), and in secondary sites that are of greater importance for Rn emanation. The main U-bearing secondary sites are weathered sphene, grain boundary coatings, weathered biotite and plagioclase, as well as dense Fe-rich coatings and a REE-phosphate mineral present in near-vertical fracture zones in saprolite underlying shallow loam. Elevated U in these sites generally correlates with high Ti, Al, Fe, and/or P. Preferential distribution of U and Ra on grain boundaries and porous weathered minerals is reflected in relatively high Rn emanation rates in the soil. Highest emanation occurs between 1.3 and 2.3 m depth, where fine pedogenic phasesgibbsite and amorphous silica and Fe-OOH—are most abundant; it is related to fixation of Ra by these phases, which precipitate close to the surface and accumulate at these depths by illuviation. Separation of Ra from U may occur locally, given remobilization of U-series elements from secondary sites, and large differences between Ra and U sorption capabilities of several phases present in the soil. Concentration of U along permeable fracture zones in saprolite suggests that contribution of soil-gas Rn from depth (> 2 m) could be significant to Rn availability near the surface.     

铀矿地质勘探设施退役整治中氡析出率快速检测

多年来我国在铀矿地质勘探取得丰硕成果的同时,也遗留了一些退役的放射性废物污染源,整治这类污染源有利于公众安全,有利于保护生态环境.整治工作中一项重要的内容,就是野外对氡(Rn)元素析出率的检测,以往的检测方法分别为局部静态法、驻极体收集积分法和活性炭吸附法.现采用HDC-90环境测氡仪可快速检测氡元素析出率.     

可地浸砂岩型铀矿储量计算中的物探参数研究

可地浸砂岩型铀矿储量计算中的物探参数有密度，湿度，铀平衡系数，镭氡平衡系数，有效原子序数和钍钾元素干扰，它们在铀矿区的变化规律和数值大小，直接影响铀矿的储量计算，本文就新疆十红滩可地浸砂岩型铀矿床储量计算中的物探参数在采样，测定，数据计算和整理，资料分析研究方面总结了一套适合可地浸砂岩型铀矿的室内外工作方法，为铀矿储量计算提供了准确的物探参数修正值，在该矿区的储量计算中达到了预期的效果。