# US 9,519,067 B1 · Radioactive gas measurement apparatus and failed fuel inspection apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,519,067 B1 - Document ID: US9519067B1 - Status: Granted - Kind: B1 - Application number: 12/886,616 - Filed: 2010-09-21 - Published: 2016-12-15 - Granted: 2016-12-13 - Earliest claimed: 2010-09-21 - Assignees: Hitachi, Ltd. - Applicants: Hiroshi Kitaguchi; Takahiro Tadokoro; Katsunori Ueno; Hitoshi Kuwabara - Inventors: Hiroshi Kitaguchi; Takahiro Tadokoro; Katsunori Ueno; Hitoshi Kuwabara - Web page: https://patentgrep.com/patent/US9519067B1 ## CPC - G01M 3/20: using special tracer materials, e.g. dye, fluorescent material, radioactive material - G01N 23/22: by measuring secondary emission from the material - G01N 33/0027: {concerning the detector} - G01N 33/0055: {Radionuclides} - G01T 1/185: with ionisation chamber arrangements - G01T 1/2935: {using ionisation detectors} - G01T 1/18: with counting-tube arrangements, e.g. with Geiger counters (tubes H01J47/08; {with alarm provision G01T7/125}) - H01J 47/02: Ionisation chambers - H01J 47/06: Proportional counter tubes - G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - G01T: MEASUREMENT OF NUCLEAR OR X-RADIATION (radiation analysis of materials, mass spectrometry G01N23/00; tubes for determining the presence, intensity, density or energy of radiation or particles H01J47/00) - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) ## Abstract A radioactive gas measurement apparatus comprises: a radiation measurement cell comprising an inlet pipe and a discharge pipe, the radiation measurement cell introducing and discharging a radioactive gas containing a nuclide to be measured and a positron emitter nuclide through the inlet pipe and the discharge pipe; a radiation detector for measuring a radiation generated from the radioactive gas; and a radiation collimator allowing the radiation measurement cell to communicate with the radiation detector and setting a predetermined radiation measurement geometry condition between the radiation measurement cell and the radiation detector. Then, as the predetermined radiation measurement geometry condition, an inner wall area of the radiation measurement cell which the radiation detector views through the radiation collimator is set equal to or less than a half of a total inner wall area of the radiation measurement cell. ## Claims ### Claim 1 A radioactive gas measurement apparatus comprising: a radiation measurement cell comprising an inlet pipe and a discharge pipe, the radiation measurement cell introducing and discharging a radioactive gas containing a nuclide to be measured and a positron emitter nuclide through the inlet pipe and the discharge pipe; a radiation detector for measuring a radiation generated from the radioactive gas; and a radiation collimator allowing the radiation measurement cell to communicate with the radiation detector and setting a predetermined radiation measurement geometry condition between the radiation measurement cell and the radiation detector, wherein as the predetermined radiation measurement geometry condition, an inner wall area of the radiation measurement cell which the radiation detector views through the radiation collimator is set equal to or less than a half of a total inner wall area of the radiation measurement cell. ### Claim 2 (depends on 1) The radioactive gas measurement apparatus according to claim 1, wherein as the predetermined radiation detection geometry condition, under a condition that a side inner wall of the radiation measurement cell is not viewed, a ratio (h/D) of a length (h) of the radiation measurement cell and a circular equivalent diameter (D) of an inner wall area existing at the farthest place of the radiation measurement cell which the radiation detector views is set to equal to or greater than 1. ### Claim 3 (depends on 1) The radioactive gas measurement apparatus according to claim 1, wherein the radiation measurement cell is columnar. ### Claim 4 (depends on 1) The radioactive gas measurement apparatus according to claim 1, wherein the radiation measurement cell is conical. ### Claim 5 (depends on 1) The radioactive gas measurement apparatus according to claim 1, wherein an index nuclide for nuclear reactor failed-fuel detection is measured as the nuclide to be measured, thereby detecting whether or not there is a failed fuel. ### Claim 6 (depends on 2) The radioactive gas measurement apparatus according to claim 2, wherein an index nuclide for nuclear reactor failed-fuel detection is measured as the nuclide to be measured, thereby detecting whether or not there is a failed fuel. ### Claim 7 (depends on 3) The radioactive gas measurement apparatus according to claim 3, wherein an index nuclide for nuclear reactor failed-fuel detection is measured as the nuclide to be measured, thereby detecting whether or not there is a failed fuel. ### Claim 8 (depends on 4) The radioactive gas measurement apparatus according to claim 4, wherein an index nuclide for nuclear reactor failed-fuel detection is measured as the nuclide to be measured, thereby detecting whether or not there is a failed fuel. ### Claim 9 A failed-fuel detection system comprising: a sampler for sampling a radioactive gas containing a nuclide to be measured and a positron emitter nuclide passing through a nuclear reactor fuel housed in a nuclear reactor; and a radioactive gas measurement apparatus for measuring a radiation generated from the radioactive gas sampled by the sampler, wherein the radioactive gas measurement apparatus comprises: a radiation measurement cell comprising an inlet pipe connected to the sampler and a discharge pipe, the radiation measurement cell introducing and discharging a radioactive gas containing a nuclide to be measured and a positron emitter nuclide through the inlet pipe and the discharge pipe; a radiation detector for measuring a radiation generated from the radioactive gas; and a radiation collimator allowing the radiation measurement cell to communicate with the radiation detector and setting a predetermined radiation measurement geometry condition between the radiation measurement cell and the radiation detector, and wherein as the predetermined radiation measurement geometry condition, an inner wall area of the radiation measurement cell which the radiation detector views through the radiation collimator is set equal to or less than a half of a total inner wall area of the radiation measurement cell. ### Claim 10 (depends on 9) The failed-fuel detection system according to claim 9, wherein as the radiation detection geometry condition, under a condition that a side inner wall of a measurement cell is not viewed, a ratio (h/D) of a length (h) of the radiation measurement cell and a circular equivalent diameter (D) of an inner wall area existing at the farthest place of the radiation measurement cell which the radiation detector views is set to equal to or greater than 1.