ENTRY 20113 20120708 22342011300000001 SUBENT 20113001 20120708 22342011300100001 BIB 14 61 2011300100002 INSTITUTE (2SWDFOA) 2011300100003 REFERENCE (J,JNE,27,395,1973) Main reference. 2011300100004 (C,70HELSINKI,2,139,1970) Preliminary data. 2011300100005 AUTHOR (L.Widen,H.Conde) 2011300100006 TITLE Prompt nu-bar values of U-235 and Pu-239 in some 2011300100007 fast reactor spectra 2011300100008 FACILITY (REAC,2SWDFOA) Fast zero-power reactor(FRO) at Studsvik2011300100009 The cylindrical reactor core consisting of uranium 2011300100010 (20% enrichment) 2011300100011 INC-SOURCE (REAC) The neutron beam from the interior or the 2011300100012 critical assembly. Moderator materials (graphite and 2011300100013 polyethylene), a copper reflector. 2011300100014 .The neutrons were extracted through a narrow hole from2011300100015 the centre of the core region and entered a 13 meter 2011300100016 long evacuated beam tube through aluminium windows. 2011300100017 Two collimators of borated paraffin were placed inside2011300100018 the beam tube to give a well-defined beam which 2011300100019 entered the fission chambers (U-235 and Pu-239). 2011300100020 These were placed in the middle of the scintillator 2011300100021 tank. 2011300100022 SAMPLE .The fissionable materials were electrodeposited 2011300100023 onto 3 thin concentric cylinders and housed in 2011300100024 thin-walled (0.2 mm of aluminium) ionization chamber. 2011300100025 METHOD (COINC) Coincidences between fission fragments and 2011300100026 prompt neutrons. 2011300100027 REL-REF (I,,T.L.Anderson+,R,AE-195,1965) - Reactor FRO 2011300100028 description 2011300100029 (M,,I.Asplund-Nilsson+,J,NSE,20,527,1964) Data analysis2011300100030 MONITOR ((MONIT1)98-CF-252(0,F),PR,NU) 2011300100031 DETECTOR (STANK) A large liquid scintillator tank, 50 cm in 2011300100032 diameter and 50 cm in length, contained about 100 2011300100033 litres of a Gd-loaded liquid (NE313)-neutron detection2011300100034 (FISCH) Fission chamber for fission fragment detection2011300100035 COMMENT .The nu-bar values averaged over the fast reactor 2011300100036 neutron spectrum were calculated with the use of 2011300100037 the program RELAT and the group constants of the 2011300100038 different energy dependent variables were calculated 2011300100039 with the program GRUSP in the multi-group structure 2011300100040 chosen. 2011300100041 CORRECTION .The observed nu values were integral values over the 2011300100042 actual reactor neutron-energy spectrum. The 2011300100043 corrections to the observed integral values are, 2011300100044 ------------------------------------------------------2011300100045 correction (per cent) * Pu-239 * U-235 2011300100046 ----------------------------------*---------*---------2011300100047 spontaneous fission * + 3.0 * --- 2011300100048 pile-up correction * - 0.1 * - 0.2 2011300100049 accidental coincidences * + 0.2 * + 0.1 2011300100050 different fission neutron spectra* - 0.5 * - 0.8 2011300100051 bias level correction * + 4.0 * --- 2011300100052 fast neutron contribution in 2011300100053 thermal runs * - 0.8 * - 0.4 2011300100054 ----------------------------------*---------*---------2011300100055 HISTORY (19701217C) 2011300100056 (19710908E) 2011300100057 (19800822A) Subents 003 and 005 deleted and included 2011300100058 in Subents 002 and 004, new main reference. 2011300100059 (19800829E) 2011300100060 (20120708A) SD: Updated to new date formats,lower case.2011300100061 corrections according last EXFOR rules and Dict. 2011300100062 SM+SD Data SUBENTs 20113002 - 20113005 recompiled. 2011300100063 ENDBIB 61 0 2011300100064 COMMON 1 3 2011300100065 MONIT1 2011300100066 PRT/FIS 2011300100067 3.756 2011300100068 ENDCOMMON 3 0 2011300100069 ENDSUBENT 68 0 2011300199999 SUBENT 20113002 20120708 22342011300200001 BIB 10 49 2011300200002 REACTION ((92-U-235(N,F),PR,NU,,FST)// 2011300200003 (92-U-235(N,F),PR,NU,,MXW)) Fast reactor spectrum 2011300200004 averaged over energy interval nu-bar values relative 2011300200005 to the nu-bar values at thermal energy. 2011300200006 INC-SPECT A fast-reactor spectrum. The energy spectrum is 2011300200007 given in fig. 2 in JNE,27,395,1973 and were calculated2011300200008 from the zero-dimensional program SPENG. 2011300200009 The measurements were made with three different reactor2011300200010 cores giving median fission energies for 235U (core 2011300200011 centre) of 50, 170 and 240 keV. 2011300200012 SAMPLE (92-U-235,ENR=0.933) The fission chamber contains 2011300200013 520 mg of 92-U-235. Isotopic abundances 93.3% U-235 2011300200014 and 6.7% U-238. 2011300200015 DETECTOR (FISCH).A fission chamber similar to those for U-235 2011300200016 and Pu-239 contains a Cf-252 source giving about 2011300200017 50 spontaneous fissions per minute. 2011300200018 PART-DET (FF,PN) Fission fragments and prompt neutrons in 2011300200019 coincidence. 2011300200020 COMMENT .To obtain a reasonable counting rate, the Pu-239 runs 2011300200021 were made with a higher reactor effect than the U-235 2011300200022 runs. The fission counting rates in the Pu-239 and 2011300200023 U-235 measurements were about 2.5 and 10 fissions per 2011300200024 minute, respectively. 2011300200025 .The time distribution of the background pulses in the 2011300200026 scintillator caused by the reactor was checked. No 2011300200027 time correlation of the background pulses could be 2011300200028 observed. 2011300200029 FLAG (3.) First reactor core position with neutron energies 2011300200030 between about 76 eV and 9 MeV. 2011300200031 Volumetric composition of the FRO core in percent: 2011300200032 Core 235U 238U C Fe Cr Ni Al Poly Void Teflon2011300200033 ethylene 2011300200034 3 11.7 46.8 29.2 4.8 1.2 0.5 5.6 0.2 2011300200035 (5.) Second reactor core position with neutron energies2011300200036 between about 0.01 eV and 9 MeV. 2011300200037 Volumetric composition of the FRO core in percent: 2011300200038 Core 235U 238U C Fe Cr Ni Al Poly Void Teflon2011300200039 ethylene 2011300200040 5 10.2 40.8 29.2 4.8 1.2 0.5 7.5 5.6 0.2 2011300200041 (8.) Third reactor core position with neutron energies 2011300200042 between about 0.1 eV and 9 MeV. 2011300200043 Volumetric composition of the FRO core in percent: 2011300200044 Core 235U 238U C Fe Cr Ni Al Poly Void Teflon2011300200045 ethylene 2011300200046 8 10.2 40.8 29.2 4.8 1.2 0.5 5.6 l.9 5.6 0.2 2011300200047 STATUS (TABLE) .Table 3 in JNE,27,395,1973. 2011300200048 ERR-ANALYS (DATA-ERR) .The total errors in the relative nu-bar 2011300200049 values were about 1.5% , mainly due to statistics. 2011300200050 HISTORY (20120708A) SM: SUBENT re-compiled 2011300200051 ENDBIB 49 0 2011300200052 COMMON 1 3 2011300200053 EN-DUM-DN 2011300200054 EV 2011300200055 2.53E-02 2011300200056 ENDCOMMON 3 0 2011300200057 DATA 4 3 2011300200058 EN-DUM-NM DATA DATA-ERR FLAG 2011300200059 KEV NO-DIM NO-DIM NO-DIM 2011300200060 50. 1.0300E+00 1.6000E-02 3. 2011300200061 170. 1.0270E+00 1.7000E-02 8. 2011300200062 240. 1.0330E+00 1.7000E-02 5. 2011300200063 ENDDATA 5 0 2011300200064 ENDSUBENT 63 0 2011300299999 SUBENT 20113003 20120708 22342011300300001 BIB 10 18 2011300300002 REACTION (92-U-235(N,F),PR,NU,,FST) Averaged over energy 2011300300003 0.0243 eV - 10 MeV 2011300300004 MONITOR (92-U-235(N,F),PR,NU) 2011300300005 INC-SOURCE (REAC) An accelerator driven core of the critical 2011300300006 reactor FRO 2011300300007 INC-SPECT .A fast-reactor spectrum. The energy spectrum is 2011300300008 given in Fig. 2 in IAEA-CN-26/59,139,1970. 2011300300009 SAMPLE .U-235 sample weight is 450 milligram. 2011300300010 DETECTOR .A fission chamber similar to those for U-235 and 2011300300011 Pu-239 contains a Cf-252 source giving about 2011300300012 20 spontaneous fissions per minute. 2011300300013 PART-DET (FF,PN) Fission fragments and prompt neutrons in 2011300300014 coincidence. 2011300300015 ERR-ANALYS (ERR-S) The statistical error in the measurement 2011300300016 of nu for 92-U-235 is 1.5%. 2011300300017 STATUS (TABLE) Data from TABLE II of 70HELSINKI,2,139,1970 2011300300018 (PRELM) By the authors 2011300300019 HISTORY (20120708A) SM: SUBENT re-compiled 2011300300020 ENDBIB 18 0 2011300300021 COMMON 1 3 2011300300022 EN-NRM 2011300300023 EV 2011300300024 2.53E-02 2011300300025 ENDCOMMON 3 0 2011300300026 DATA 4 1 2011300300027 EN-MIN EN-MAX DATA ERR-S 2011300300028 EV EV PRT/FIS PRT/FIS 2011300300029 2.53E-02 1.0 E+07 2.481 0.037 2011300300030 ENDDATA 3 0 2011300300031 ENDSUBENT 30 0 2011300399999 SUBENT 20113004 20120708 22342011300400001 BIB 9 49 2011300400002 REACTION ((94-PU-239(N,F),PR,NU,,FST)// 2011300400003 (94-PU-239(N,F),PR,NU,,MXW)) Fast reactor spectrum 2011300400004 averaged over energy interval nu-bar values relative 2011300400005 to the nu-bar values at thermal energy. 2011300400006 INC-SPECT A fast-reactor spectrum. 2011300400007 The measurements were made with three different reactor2011300400008 cores giving median fission energies for 235U (core 2011300400009 centre) of 50, 170 and 240 keV. 2011300400010 SAMPLE .The fissionable materials were electrodeposited 2011300400011 onto thin parallel aluminum plates and housed in 2011300400012 thin-walled (0.2 mm of aluminium) ionization chamber. 2011300400013 .The fission chamber contains 30 mg of 94-Pu-239. 2011300400014 .a fission chamber similar to those for U-235 and 2011300400015 Pu-239 contains a Cf-252 source giving about 2011300400016 50 spontaneous fissions per minute. 2011300400017 PART-DET (FF,PN) Fission fragments and prompt neutrons in 2011300400018 coincidence. 2011300400019 COMMENT .To obtain a reasonable counting rate, the Pu-239 runs 2011300400020 were made with a higher reactor effect than the U-235 2011300400021 runs. The fission counting rates in the Pu-239 and 2011300400022 U-235 measurements were about 2.5 and 10 fissions per 2011300400023 minute, respectively. 2011300400024 .The time distribution of the background pulses in the 2011300400025 scintillator caused by the reactor was checked. No 2011300400026 time correlation of the background pulses could be 2011300400027 observed. 2011300400028 FLAG (3.) First reactor core position with neutron energies 2011300400029 between about 90 eV and 9 MeV. 2011300400030 Volumetric composition of the FRO core in percent: 2011300400031 Core 235U 238U C Fe Cr Ni Al Poly Void Teflon2011300400032 ethylene 2011300400033 3 11.7 46.8 29.2 4.8 1.2 0.5 5.6 0.2 2011300400034 (5.) Second reactor core position with neutron energies2011300400035 between about 0.01 eV and 9 MeV. 2011300400036 Volumetric composition of the FRO core in percent: 2011300400037 Core 235U 238U C Fe Cr Ni Al Poly Void Teflon2011300400038 ethylene 2011300400039 5 10.2 40.8 29.2 4.8 1.2 0.5 7.5 5.6 0.2 2011300400040 (8.) Third reactor core position with neutron energies 2011300400041 between about 0.1 eV and 9 MeV. 2011300400042 Volumetric composition of the FRO core in percent: 2011300400043 Core 235U 238U C Fe Cr Ni Al Poly Void Teflon2011300400044 ethylene 2011300400045 8 10.2 40.8 29.2 4.8 1.2 0.5 5.6 l.9 5.6 0.2 2011300400046 ERR-ANALYS (DATA-ERR) The total error was about 2%, including un- 2011300400047 certainties in the spontaneous fission, bias level 2011300400048 corrections and statistics. 2011300400049 STATUS (TABLE) .Table 3 in JNE,27,395,1973. 2011300400050 HISTORY (20120708A) SM+SD SUBENT re-compiled 2011300400051 ENDBIB 49 0 2011300400052 COMMON 1 3 2011300400053 EN-DUM-DN 2011300400054 EV 2011300400055 2.53E-02 2011300400056 ENDCOMMON 3 0 2011300400057 DATA 4 3 2011300400058 EN-DUM-NM DATA DATA-ERR FLAG 2011300400059 EV NO-DIM NO-DIM NO-DIM 2011300400060 50. 1.0090E+00 1.9000E-02 3. 2011300400061 170. 1.0100E+00 2.7000E-02 8. 2011300400062 240. 1.0260E+00 1.6000E-02 5. 2011300400063 ENDDATA 5 0 2011300400064 ENDSUBENT 63 0 2011300499999 SUBENT 20113005 19830913 00002011300500001 BIB 7 21 2011300500002 REACTION (94-PU-239(N,F),PR,NU,,SPA) 2011300500003 AVERAGE OVER THE REACTOR SPECTRUM FROM 0 TO 67.4 KEV. 2011300500004 SAMPLE .THE FISSIONABLE MATERIALS WERE ELECTRO- 2011300500005 DEPOSITED ONTO THIN PLATINUM PLATES AND HOUSED IN 2011300500006 THIN-WALLED (0.2 MM OF ALUMINIUM) IONIZATION CHAMBER. 2011300500007 .THE FISSION CHAMBER CONTAINS 20 MG OF 94-PU-239. 2011300500008 .A FISSION CHAMBER SIMILAR TO THOSE FOR U-235 AND 2011300500009 PU-239 CONTAINS A CF-252 SOURCE GIVING ABOUT 2011300500010 20 SPONTANEOUS FISSIONS PER MINUTE. 2011300500011 ANALYSIS .ONE DIMENSIONAL DIFFUSION THEORY WITH A 34 GROUP 2011300500012 REACTOR SPECTRUM. 2011300500013 PART-DET (FF,PN) FISSION FRAGMENTS AND PROMPT NEUTRONS IN 2011300500014 COINCIDENCE. 2011300500015 COMMENT .THE FINAL CORRECTED NU-VALUES ARE AVERAGES OVER THE 2011300500016 FAST REACTOR SPECTRUM FROM 0 TO 67.4 KEV. 2011300500017 HISTORY (701217C) 2011300500018 (710908E) 2011300500019 (800822D) THIS SUBWORK INCLUDED IN SUBWORK 004. 2011300500020 (800829D) 2011300500021 ERR-ANALYS .THE STATISTICAL ERROR IN THE MEASUREMENT OF NU FOR 2011300500022 94-PU-239 IS 1.9 PER CENT. 2011300500023 ENDBIB 21 0 2011300500024 NOCOMMON 0 0 2011300500025 NODATA 0 0 ALL POINTS ELIMINATED FROM SET 2011300500026 ENDSUBENT 25 0 2011300599999 ENDENTRY 5 0 2011399999999