本文从不等式角度推导了低本底 α、β 测量仪测量过程中净计数率探测下限的公式,并计算两种典型探测下限公式对应的犯第二类错误的实际概率值.在不做近似的情况下,一定时间发生原子核衰变的数目服从二项分布.当净计数率的平均值为探测下限这个值时,净计数率的随机数低于判断限的概率就是犯第二类错误的实际概率值.结合初始时刻的放射性原子核数目、整个测量时间发生了衰变的放射性原子核数、放射性原子核发生衰变的概率,可以计算犯第二类错误(产生误判)的实际概率值.通过计算,发现大多数情况下犯第二类错误的实际最大概率比标称概率值低1到2个量级.因此在保证犯第二类错误的实际概率值趋近并小于标称值的情况下,通过引入修正系数对探测下限进行了修正.通过计算发现,当kα=1.645,kβ=1.645时,通过引入修正系数可以使探测下限至少降低22％.

移动式屏蔽检查热室可模块化地拆卸、运输、组装并实现简单检查功能,具备了较好的机动性和灵活性.但同时,由于要兼顾机动性和灵活性,带来了辐射防护工作实施的一系列新问题.为解决相关问题,本文在参考现有核设施辐射防护体系建设标准的基础上,梳理了移动式屏蔽检查热室辐射防护剂量限制体系,开展了移动式屏蔽检查热室辐射防护解决方案研究,从源项及屏蔽、通排风、辐射分区及管理、辐射监测、事故处理等要素进行了相关细化考虑.

针对废树脂焚烧灰的玻璃固化配方,通过测量低温区温度-黏度关系进行退火工艺研究,结果表明:该配方玻璃固化过程中的转化温度为545℃,软化温度为618℃,应变点温度为525℃,退火点温度为575℃,确定该配方玻璃固化过程的适宜退火温度为525～555℃.

为了使反应堆压力容器主螺栓受力更加均匀,提高工作效率,设计了能同时实现4组主螺栓拉伸的反应堆压力容器主螺栓拉伸装置.该装置具有4台串联的液压螺栓拉伸器,通过十字旋转支架实现4台液压螺栓器工位变换,旋转支架的升降、旋转以及主螺栓拉伸状态显示通过PLC控制;应用商业软件ANSYS对关键部件进行了力学校核.工程应用证明,该装置各项技术指标满足压力容器主螺栓卸载/加载要求.

通过计算热中子利用率来估算靶件对堆芯反应性的影响,同时使用燃料管理程序进行校算.估算结果表明,堆芯80盒元件可装氮化铝靶料4000 g,对反应性的影响约为-250×10-5,使堆芯寿期缩短约60MW·d; 14C的年产量可达1.0×1012 Bq.高通量工程试验堆(HFETR)的堆芯核设计和运行结果表明,该估算是正确、合理的.

A new monitoring technology for control rod position is developed by utilizing the FPGA(Field-Programmable Gate Array) platform and using the SOPC(System On Programmable Chip) technology.In this SOPC system,Nios II CPU,VGA(Video Graphics Array)display controller and CAN(Controller Area Network) bus controller are integrated in one FPGA chip.Thus the SOPC hardware platform with comprehensive functionality is constructed.Based on this SOPC platform,the real time data of control rod position indication system can be vividly displayed on the LCD and stored in the external nonvolatile RAM as history records.Therefore,the operator can obtain the overall operation status of control rod position indication system quickly and conveniently.The developed prototype has proved the feasibility of this technology.

For the monitoring of high γ-dose rate,the handheld device is widely used,thus causes high personnel radiation exposures.For the above reasons,a special wireless equipment is designed.It is composed of a detector,a transmitter and a reading device.During measurement,the detector is delivered to the target area by tools.The operator can record the readings in a safe area.The equipment can communicate normally in very bad shielded wireless communication environments,thanks to the wireless transmitter.The detector is an ionization chamber with the upper measurement range of 100Gy/h.The weight of the detector is less than 900g.The smooth surface and omni seal structure design can reduce the opportunity of being contaminated.Even if the detector falls under disastrous conditions,it can float on shielding pond,without causing accident.To solve the problem of inner electronics working life being reduced under strong radiation damage,the electronics part is module-designed.There is a spare part,appropriate for replacing by the user.Hardware and software measures are applied to ensure that the efficiency factor will not change after replacing the electronics module and no recalibrating is needed.An inner counter will record the remaining module working life,alarming the user to replace at the proper time.The apparatus is successfully used in the hot cell of HFETR.The equipment has great potentials in radiation protection for measurement of high γ-dose rate targets.