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Conference Spotlight
2025 ANS Winter Conference & Expo
November 9–12, 2025
Washington, DC|Washington Hilton
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High temperature fission chambers engineered for AMR/SMR safety and performance
As the global energy landscape shifts towards safer, smaller, and more flexible nuclear power, Small Modular Reactors (SMRs) and Gen. IV* technologies are at the forefront of innovation. These advanced designs pose new challenges in size, efficiency, and operating environment that traditional instrumentation and control solutions aren’t always designed to handle.
Bruno Bärs, Esko Markkanen
Nuclear Science and Engineering | Volume 48 | Number 2 | June 1972 | Pages 202-210
Technical Paper | doi.org/10.13182/NSE72-A22471
Articles are hosted by Taylor and Francis Online.
Rossi-alpha auto- and cross-correlation measurements on a large subcritical assembly using an in-core neutron detector and in-core and ex-core photon detectors are reported. The correlation amplitude and the main relaxation constant were determined in each measurement. The relaxation constants ( = 4090 1/sec) and the nine relative correlation amplitudes obtained were used to determine four space damping factors and some basic parameters describing the sources of correlated fluctuations.By utilizing some basic fission parameters (⟨v⟩, ⟨v2⟩, spontaneous fission probability) and the effective multiplication factor (k = 0.788) from pulsed-neutron source measurements or from computations, estimates for the prompt-neutron lifetime (l = 53.2 µsec), the equivalent number of free neutrons (⟨y0⟩= 5.24) in the reactor, the mean fission rate (αf⟨y0⟩ = 73 800 1/sec) and the efficiency (€nl = 8.1 × 10-4) of the neutron detector could further be determined.The results verify the applicability of the gamma observation technique in reactor noise measurements as a substitute and a complement to noise measurements via neutron detection.
