从混合裂变产物中放化分离132I

依据混合裂变产物中碘及其母体碲的同位素的半衰期设计分离¹³²I的流程。该流程的主要步骤为浓HBr蒸发和CCl₄萃取。实验研究了浓HBr蒸发对碘的去污效果；在硝酸介质中，用含I₂的CCl₄作为萃取剂，研究了HNO₃浓度、水相中KI含量和有机相CCl₄中I₂含量对¹³²I萃取率的影响，测定了含SO₂水溶液对¹³²I的反萃率。用设计的推荐流程获得了放化纯的¹³²I，其中含有的¹³¹I的活度为¹³²I的1.3％，分离流程全程对¹³²I的化学回收率约为60％，流程对主要γ核素的去污因子大于10³。     

中美甲状腺摄131I率计算方法一致性研究

为了探讨美国核医学会和中国卫生部诊疗常规方法测定甲状腺摄¹³¹I率结果的一致性,对2011年4月在本科就诊的122例甲状腺相关疾病患者分别采用美国甲状腺摄¹³¹I率指南和中国中华医学会出版的临床诊疗指南核医学分册常规方法测定6 h和24 h摄¹³¹I率,并对结果进行分析。结果显示,两种方法所测6 h和24 h甲状腺摄¹³¹I率均值无显著性差别（P>0.05）;两种方法测定结果呈高度正相关,相关系数分别为1.000和0.999（P<0.000 1）;Bland Altman作图法证实,中美两种方法所测数据具有较高的一致性。以上结果表明,美国和中国常规方法测定甲状腺摄¹³¹I率结果具有高度一致性,两种方法可以相互替代,中国方法操作更为简便,实用性更强。     

3-三甲基硅苄胍的合成及其125I标记

以3-溴甲苯为起始物，通过5步反应合成可用于放射性碘（砹）标记的3-三甲基硅苄胍，并用核磁共振（NMR）、质谱（MS）、高效液相（HPLC）等对产物进行了表征。以此化合物为前体，对其进行了¹²⁵I标记。¹²⁵I MIBG的标记率达66.7%，放化纯度＞98%。标记物在室温下放置3d后，放化纯度无明显变化，表明¹²⁵I MIBG具有较高的体外稳定性。     

放射敏感性启动子调控CD基因/5-FC自杀系统慢病毒载体的构建及125I诱导表达的研究

合成了含8个CArG元件的放射敏感性启动子E8,将其连接于胞嘧啶脱氨酶（Cytosine Deaminase, CD）基因及GFP报告基因上游,构建了重组慢病毒载体pGC-FU-E8-codA-GFP。与慢病毒包装系统共转染293T细胞包装重组慢病毒颗粒E8-codA-GFP LV,研究重组慢病毒感染EJ细胞在不同剂量¹²⁵I的电离辐射下绿色荧光表达情况及其将5-FC转化为5-FU的能力。结果显示：构建的含有E8启动子及CD基因的重组慢病毒载体,包装的重组慢病毒滴度为2×10⁸TU/mL;经¹²⁵I照射的重组慢病毒感染EJ细胞均可观察到绿色荧光,其细胞上清液均可检测到5-FC转化成的5-FU紫外峰,其中55.5 kBq及74.0 kBq ¹²⁵I照射的细胞组绿色荧光明显,148 kBq ¹²⁵I照射的细胞组,其5-FU紫外峰最为明显。以上结果表明：本工作所构建的放射敏感性启动子调控CD基因/5-FC自杀系统重组慢病毒载体具有电离辐射调控作用,可在¹²⁵I的电离辐射作用下诱导下游基因表达,为放射性核素¹²⁵I联合CD基因/5-FC自杀系统对肿瘤细胞的治疗作用研究提供了实验基础。     

125I粒子组织间植入近距离治疗恶性肿瘤

采用¹²⁵I粒子植入法对20例恶性肿瘤患者的24个病灶进行治疗,以评价¹²⁵I粒子组织间植入恶性肿瘤的可行性及不良反应。术前制定肿瘤组织间三维立体定向放射治疗计划,在全麻剖腹直视下、全麻腹腔镜下或局麻CT、局麻彩色多普勒导向下经皮穿刺将¹²⁵I粒子植入恶性肿瘤病灶内。20例患者¹²⁵I粒子植入均顺利完成,术中及术后1周观察粒子在病灶内的分布基本与计划相符合,未观察到粒子迁移;术中及术后不良反应较为轻微且易于处理;多数患者临床症状得到不同程度的缓解,血清肿瘤标志物水平呈现不同程度的下降; 病情完全缓解（CR）20.00%（4/20例）, 部分缓解（PR）35.00%（7/20例）, 稳定（SD）30.00%（6/20例）,进展（PD）15.00%（3/20例）,总有效率（CR+PR）55.00%（11/20例）。以上结果表明,¹²⁵I粒子组织间植入近距离内放射治疗恶性肿瘤施术方便、安全有效,具有较高的临床价值,值得进一步推广及深入研究。     

131I治疗对SD大鼠血清降钙素水平的影响

为了研究SD大鼠甲状腺经不同剂量¹³¹I内照射后,短期内C细胞损伤情况及对大鼠血清降钙素（calcitonin,CT）水平和CT储备功能的影响,将30只SD大鼠随机分成对照组、小剂量组、大剂量组,分别测定给Na¹³¹I前及给Na¹³¹I一月后血清降钙素水平,并通过钙负荷-降钙素释放试验测定降钙素储备功能。结果显示：给Na¹³¹I后小剂量组和大剂量组CT基础值、经钙负荷后降钙素峰值、升高幅度均明显降低,与给药前有显著差异（P＜0.05）。且不同剂量间CT基础值、降钙素峰值及升高幅度均有显著性差异。甲状腺组织CT免疫组化染色结果显示,照射后C细胞数量及分布密度明显降低。因此认为,¹³¹I治疗后大鼠血清CT水平减低,CT储备功能下降,其减低程度与¹³¹I剂量有相关性。     

利用航测数据反推福岛核事故137Cs的释放量

日本福岛第一核电站发生事故后,造成大量的放射性物质释放。为准确评估事故的释放量,本文根据美国公布的航测¹³⁷Cs地面沉积浓度图和日本福岛第一核电站事故发生后观测的气象数据,利用拉格朗日烟团模式反推¹³⁷Cs的释放量,并通过计算估算日本福岛第一核电站核事故向大气释放的¹³¹I当量,约为1.07×10¹⁸Bq,估算结果与日本政府公布的估算结果接近。     

压水堆中嬗变99Tc和129I的计算研究

选取大亚湾压水堆作为嬗变参考堆,研究在压水堆中嬗变长寿命裂变产物⁹⁹Tc和¹²⁹I的可行性。计算结果表明：在1个换料周期（18个月）内,⁹⁹Tc的最大嬗变率为15.69%,¹²⁹I的最大嬗变率为9.18%。通过对不同堆芯方案进行安全性分析发现：添加⁹⁹Tc和¹²⁹I后,堆芯有效增殖因数k_eff降低且随燃耗变化的幅度变小;堆芯径向中子通量密度分布无明显变化但径向功率峰因子降低;考虑燃料温度系数、慢化剂温度系数、硼微分价值以及控制棒价值等,得出在反应性温度系数及反应性控制方面不会导致安全问题,相反有优化作用。因此,从安全角度分析,在压水堆中嬗变⁹⁹Tc和¹²⁹I是可行的。     

125I-NGF在小鼠体内的血药浓度-时间过程

本研究涉及应用Idogn法对神经生长因子（NGF）进行¹²⁵I标记,并用同位素示踪法与电泳法相结合的方法研究¹²⁵I- NGF在小鼠体内的血药浓度时间过程。结果显示，静脉注射 ¹²⁵I- NGF在小鼠体内的代谢规律符合二房室开放模型。分布相半衰期为0.13h，消除相半衰期为3.68h，¹²⁵I-NGF在小鼠体内分布和消除均较快，清除率为0.125L•h^-1•kg^-1，表观分布容积为0.697L•kg^-1，曲线所围面积为16.01μg•h•L^-1。     

基于SnF2靶样的加速器质谱测量裂变产物126Sn的方法研究

在中国原子能科学研究院HI-13串列加速器质谱系统上建立了以SnF₂为靶样,引出SnF₃^-分子负离子形式的¹²⁶Sn-AMS分析方法。介绍了用于AMS测量的¹²⁶Sn实验室参考标准的研制以及靶物质SnF₂的化学制备过程,通过引束实验确定了可将同量异位素¹²⁶Te本底干扰压低2～3个量级的SnF₃^-分子负离子引出形式,实现了¹²⁶Sn束流的传输以及同量异位素的探测和鉴别。对制备的3个标准样品（¹²⁶Sn/Sn原子个数比为1.033×10^-8、4.54×10^-9、6.43×10^-10）的测量结果显示,¹²⁶Sn/Sn原子个数比测量值与标称值呈良好的线性关系（R²=0.999）,通过测量空白样品获得系统探测¹²⁶Sn测量的灵敏度为（1.92±1.13）×10^-10。     

Determination of the 129I transmutation rate and 129I(n, 2n)128I correction using gas mass spectrometry

Two groups of ¹²⁹I and ¹²⁷I targets were analyzed using a gas quadrupole mass spectrometer (QMS) to determine the transmutation rates via the melting method. Sodium iodide was chosen to make the target. The iodine composition in the ¹²⁹I targets is 82.7% ¹²⁹I and 17.3% ¹²⁷I. The transmutation rate of the ¹²⁹I(n, γ)¹³⁰I reaction was determined by measuring the ¹³⁰Xe with QMS. An equivalent corrective method was brought out to correct the ¹²⁹I(n, 2n)¹²⁸I branch which is interfered with by the ¹²⁷I(n, γ)¹²⁸I reaction. And the correction formula was deduced in theory. For very little ¹²⁸Xe from the ¹²⁹I(n, 2n)¹²⁸I reaction, the equivalent corrective method could not be suitable here. However, it is suitable for the mass of ¹²⁸Xe from ¹²⁹I(n,2n)¹²⁸I reaction that reaches the accurately detective level of the mass spectrometry.     

Increasing 129I Transmutation Efficiency

The special features of ¹²⁹I transmutation are discussed. The changes in content and equilibrium concentration of ¹²⁷I in a target under recycling are calculated, and the conditions for decreasing the required radiochemical capacity in reprocessing of iodine are found. It is shown on the basis of an analysis of the neutron consumption in targets and estimates of the pressure of daughter xenon under the casing that the gaseous products of transmutation must be removed during the irradiation process along a loop channel. To increase the effectiveness and safety of ¹²⁹I burnup, it is recommended that ¹²⁹I be included in the volume of the gas permeable porous nuclear-inert targets by permeation with melts of iodine compounds.     

压水堆高放长寿命裂变产物堆内嬗变平衡循环设计

基于压水堆多燃料循环管理计算,进行长寿命裂变产物（LLFP）核素堆内嬗变分析。基于长寿命裂变产物核素在乏燃料中的比重及核素的放射毒性,¹²⁹I和⁹⁹Tc作为当前嬗变研究的主要裂变产物。为避免碘同位素分离,参照乏燃料中¹²⁷I和¹²⁹I的组分比例,设计当前的碘化物嬗变靶件。将嬗变核素均匀弥散在惰性慢化材料ZrH₂中,放置在控制棒导向管内进行嬗变分析计算。基于该嬗变组件设计方案,对不同的换料方案进行评价和比较,进而搜索嬗变平衡循环。计算显示,当前带有靶件组件的布料方案可达到平衡循环,并能实现LLFP的嬗变。进一步嬗变优化方案设计受限于当前嬗变组件设计。     

Study on the LLFPs transmutation in a super-critical water-cooled fast reactor

The performance of the super-critical water-cooled fast reactor (Super FR) for the transmutation treatment of long-lived fission products (LLFPs) was evaluated. Two regions with the soft neutron spectrum, which is of great benefit to the LLFPs transmutation, can be utilized in the Super FR. First region is in the blanket assembly due to the ZrH_1.7 layer which was utilized to slow down the fast neutrons to achieve a negative void reactivity. Second region is in the reflector region of core like other metal-cooled fast reactors. The LLFPs selected in the transmutation analysis include ⁹⁹Tc, ¹²⁹I and ¹³⁵Cs discharged from LWR or fast reactor. Their isotopes, such as ¹²⁷I, ¹³³Cs, ¹³⁴Cs and ¹³⁷Cs were also considered to avoid the separation. By loading the isotopes (⁹⁹Tc or ¹²⁷I and ¹²⁹I) in the blanket assembly and the reflector region simultaneously, the transmutation rates of 5.36%/GWe year and 2.79%/GWe year can be obtained for ⁹⁹Tc and ¹²⁹I, respectively. The transmuted amounts of ⁹⁹Tc and ¹²⁹I are equal to the yields from 11.8 and 6.2 1000 MWe-class PWRs. Because of the very low capture cross section of ¹³⁵Cs and the effect of other cesium isotopes, ¹³⁵Cs was loaded with three rings of assemblies in the reflector region to make the transmuted amount be larger than the yields of two 1000 MWe-class PWRs.Based on these results, ⁹⁹Tc and ¹²⁹I can be transmuted conveniently and higher transmutation performance can be obtained in the Super FR. However, the transmutation of ¹³⁵Cs is very difficult and the transmuted amount is less than that produced by the Super FR. It turns out that the transmutation of ¹³⁵Cs is a challenge not only for the Super FR but also for other commercial fast reactors.     

Studies on LLFP transmutation in a pressurized water reactor

A systematic study on the long-lived fission product (LLFP) transmutation in a pressurized water reactor (PWR) is performed, aiming at an optimal transmutation strategy for present nuclear energy development. The LLFPs selected in the analysis include ⁹⁹Tc and ¹²⁹I discharged from light water reactors (LWRs). The isotope ¹²⁷I is also considered to avoid the difficulties in isotopes separation. To minimize the negative impacts of LLFPs on the core performance and safety parameters, metallic technetium or MgI₂ target pins mixed with ZrH₂ are designed and investigated. Through the numerical analysis on equilibrium cycles, the transmuted amounts of ⁹⁹Tc and ¹²⁹I equal to the yields from 1.94 and 4.22 PWRs with a power of 1000 MWe, respectively. Numerical results indicate that both ⁹⁹Tc and ¹²⁹I can be transmuted conveniently in present PWRs in the form of target pins.     

压水堆嬗变长寿命裂变产物的弹棒事故安全性研究

为分析压水堆(PWR)嬗变长寿命裂变产物(LLFP)的堆芯瞬态安全性,基于CASMO-4、RSIM以及改进的NLSANMT/COBRA-4程序搭建了程序系统,并利用该系统研究了嬗变堆芯在弹棒事故下的安全特性,分析了寿期初和寿期末事故发生后的功率变化及燃料中心温度变化。数值结果表明:与参考PWR相比,装载99 Tc将会使温度系数变得更负,因此弹棒事故下峰值功率降低,而装载129I则相反;装载这两种裂变产物时,燃料中心温度最高可升高127~157℃,仍距UO2芯块熔化限值温度有较大裕量。     

中子活化分析在当代无机痕量分析计量学中的作用Ⅲ. NAA用于多元素取样行为的定量表征

讨论了研制适用于微分析质控的新一代有证标准物质(CRM)的必要性,以及NAA在新一代CRM认证中的作用。归纳了NAA在当代无机痕量分析计量学发展中的三个作用：NAA作为比较基准法的国际承认,将对现代CRM质量的提高作出贡献;k0-NAA的同时使用,将进一步增强相对法NAA的基准法地位;NAA在适用于微分析质控的新一代CRM认证中将发挥不可替代的作用。     

聚变驱动的次临界系统嬗变MA的研究

一种嬗变次锕系核素(MA)的聚变驱动次临界包层的概念设计被提出。利用MCNP+ORIGEN2对次临界嬗变包层的能量放大倍数(M)、氚增殖比(TBR)、第一壁负载等中子学参数进行了分析。在保证这些参数满足设计要求的前提下,分析了两种不同的装载方案对MA嬗变能力的影响,最终MA的嬗变率能达24.3%,嬗变支持比为28。研究表明,该聚变驱动次临界嬗变包层能有效嬗变MA。     

The concept of proliferation-resistant, environment-friendly, accident-tolerant, continual and economical reactor (PEACER)

In an effort to ameliorate generic concerns with current power reactors such as the risk of proliferation, radiological hazard of the spent fuel, and the vulnerability to core-melt accidents, the concept of a revolutionary reactor, named PEACER, has been developed as a proliferation-resistant waste transmutation reactor based on the unique combination of technologies of a proven fast reactor and the heavy liquid metal coolant. In this paper, results of the PEACER conceptual design are presented by focusing on the estimated performance of the PEACER system. The proliferation resistance of PEACER is based upon both institutional and technical issues. The latter includes denaturing of fissile materials, Pu in particular, as well as the intense radiation field associated with the pyrochemical partitioning method. When the fuel volume fraction and the core aspect ratio(L/D) are optimized, the transmutation capability of PEACER for long-lived wastes from LWR spent fuels is found to exceed the production rate of two LWR's with the same electric rating. In contrast with current power reactor design principles, the lower power density and the higher neutron leakage rate lead to higher performance with respect to proliferation-resistance, transmutation capability and the accident-tolerance. Results of the present conceptual design show promising characteristics in all the five targets proposed by its name PEACER, which warrants more detailed study.     

Evaluation on transmutation performance of minor actinides with high-flux BWR

The performance of high-flux BWR (HFBWR) for burning and/or transmutation (B/T) treatment of minor actinides (MA) and long-lived fission products (LLFP) was discussed herein for estimating an advanced waste disposal with partitioning and transmutation (P&T). The concept of high-flux B/T reactor was based on a current 33 GWt-BWR, to transmute the mass of long-lived transuranium (TRU) to short-lived fission products (SLFP). The nuclide selected for B/T treatment was MA (Np-237, Am-241, and Am-243) included in the discharged fuel of LWR. The performance of B/T treatment of MA was evaluated by a new function, i.e. [F/T ratio], defined by the ratio of the fission rate to the transmutation rate in the core, at an arbitrary burn-up, due to all MA nuclides. According to the results, HFBWR could burn and/or transmute MA nuclides with higher fission rate than BWR, but the fission rate did not increase proportionally to the flux increment, due to the higher rate of neutron adsorption. The higher B/T fraction of MA would result in the higher B/T capacity, and will reduce the units of HFBWR needed for the treatment of a constant mass of MA. In addition, HFBWR had a merit of higher mass transmutation compared to the reference BWR, under the same mass loading of MA.