Npre 402 Exams

— A \ NPRE 402 Nuclear Power Engineering Fall 2014, First Midterm el Please answer all questions. Use the back of the answer sheet as needed. \ Name: ©\\e oo MeAcs Question 1; 3 A fusion process uses the ;:B" fusion reaction producing a C'? nucleus in its excited state. This excited C'? nucleus decays to Be® and He®. Be® within 10™ sec further decays into two more He nuclei. This is the only nuclear-energy releasing process in that releases fusion energy and helium nuclei, but no initial neutrons. m(,H') =1.0078250 amu, m(,B") = 11.0093055 amu, m(, He') = 4.0026032 amu 1 amu =931.481 MeV ] t v et 98 o Q= 93106 [(t o5 oszosh) Y by By oC" = Rels, Het TS es2 0 = (3 0ot03n)] ETBEE T et ety g = - ? + ? H e \ v — 747 > 2 (,u *6%”9\31\49.“-! Question 2: Compute the thicknesses of a Pb shield that would attenuate a beam of 1 MeV gamma rays with a build-up factor of B = 2, to one billionth of its initial strength, given that its linear attenuation coefficients at 1 MeV is 0.8 cm™., S facenesS = Ux107! e | Question 3: The isotope g, Thallium®® has a half life @nd c b&ased-flman@;hnology power source device. It decays through beta emission into g, with a ching ratio of 97.Dpercent with an average decay energ also e_c_@&through electron capture to goHg™"* with a branching ratio percent with a decay energy 0£-0.347 MeV. N Calculate the energy release per decay event in [MeV/disintegration] Calculate its total specific activity in [Becquerels / gm]. Calculate its total specific activity in [Curies / gm]. Calculate the specific power generation in [Watts(th) / gm]. For a 100 Watts of thermal (Eower in a Radioisotope Heating Unit (RHU) power generator, how many grams of g, Thallium®* are needed? 6. After 3.78 years of operation, what would its power become? Use: 1 MeV/sec = 1.602x10™ Watts, A, = 0.602x10* [nuclei/mole], 1 Curie = 3.7x10'"° Bq. L E = 001 (p 16U Mev) + 6026 (0. 30 Mel) 40191007 MeV/dsimetiion v G B9 (1) N - g S G ey [ MW \T\ 0" o fi‘ \G x\ %j@ 31 NbxI10P R \ core. | X =~ L\(O \—\ \ l q 3x1Q° B , >Te ¢ m —> on o\

N 2 N .k\'w ,_’LX_‘\"\) K {q‘\ L ) NPRE 402 Nuclear Power Engineering Spring 2015, First Midterm Please answer all questions. Show details of your calculations. Use the back of the answer sheet if needed. No extra sheets are {. 5- Name; Ta"}\o‘ 427?5, } 5 P, P / v Question 1 »\% The isotope g Thallium™ has a half-life o{3.78 yearsyind may be used as a nanotechnology and Micro Electro NG Mec?oa}nigal Systems (MEMS) power source. T{i§@ pure beta emitter without gamma rays emission. It decays into N\“\ anb witha branchmgzgi\tio of 97.1 percent with a decay energy of 0.764 MeV/disintegration. It also decays through N~ electron capture to gHg™ with a branching ratio of 2.9 percent with a decay energy of 0.347 MeV/disintegration. %4 P . Calculate the average energy release per decay event in [MeV/disintegration] A 3. Calculate its total specific activity in [Curies/gm). 1. " 4 Calculate the specific thermal power generation in [Watts(thygm]. Q“‘/ M /8. For a 100 Watts of thermal power in a Radioisotope Heating Unit (RHU) power generator, how many grams of 1e nghalliumzo‘ are needed? A \ /V After 3.78 years of operation, what would its thermal power become? By 7. The Cassini space probe to Saturn needs an electrical supply of 1 kWe ( kiloWatt(e)) of power. If it were powered 2. Calculate its total specific activity in [Becquerels/gm]. ( g p-oe by a Radioisotope Thermoelectric Generator (RTG) operating at a conversion efficiency of 50 percent, what would be /PV the needed amount of 8,"I'ha1131ium2°4? N N N Use: 1 MeV/sec=1.602x10" Watts, A,=0.602x10* [nuclei/mole], 1 Curie=3.7x10'° Bq. 752 MeV/ 45 tamtrer { M 1\a= ( a7l5(o.7e‘{ Mev /iy aton) x (,024Y0-347 MV /I;s:wkwi'?g) =(¢=0.7>2 ol j v R 23 3 ' ¢ INT, -3 P A5 Mags| 2 v Omf01C 180t s A= o). (6-0210 ) 2\, 72 10 B¢/y™ f\ ‘) n- Ve Vdag | \ne Lmin (\.M?y\(fllg) (20‘4 {)) M 33, | | Gre k —> ‘/Q_‘EM ?)) . 72x0 m {"‘3 740 0" %T, = Lli_és (uies [om fw A fusion process uses the gB“ fusion reaction producing a C'? nucleus in its excited state. This excited C'2 nucleus decays to Be® and He*. Be® within 10" sec further decays into two more He® nuclei. This is the only known nuclear- energy releasing process that releases fusion energy and helium nuclei, but no initial neutrons. m(,H") =1.0078250 amu, m(,B") =11.0093055amu, m(,He") = 4.0026032 amu , 1 amu =931 481 MeV 1. Balance the nuclear reactions. _ lbbm{(' 267$250,m, ¢ 11:0043059 amu) °<3 4. 00260R "”)l 2. Calculate the Q value of thg ggg@uggctinn.--- = 4 { o 1 12¢ i } ? +.B"> C '\& W ;sl ',‘,"(d . ‘5m:0.00“52°4 any C" - B+ ? | - i te | 6 . | W& Bty L Qeam @5‘_'{%] foev) B - ? + 7 8@1 v 4 | i - Ue « He | J 4 T T g (oot an¥asl 40K < 5 i . R 7T > 1 Wb AN Question 3 ,\_ g Write down the units of the following radiological quantities: Radiological Quantity Conventional System Unit SI System Unit Activity Ba X X g 5=t Absorbed Dose ? > ke =1 % ~ Using the law of radioactive decay calculate the fraction of the tritium isotépe (No-K(t)/No decaying into the He isotope. The half-life of tritum is 12.33 years. 11121233 5 N v 1 Y al A~ Within 1 year. N (_ (n(l)/ @0 D < Fo ,0,‘1‘\5 |- 0,055 W5 Muwye N_ -7 _ L5 = exp 2.3 9 ~*e 2. Within 12.33 years. ** M " \ N E) 50 hes J{,“V)“j Ne 5 A Wibin2466yers o () anw)): %05 1-%.-|0 : N N B} V Question 4 > %--‘”P(‘CP’\“)/D.SS\gf)éq.bé%')}ffu'0'25 | No ~ 0:75 s deau ){l 1. Assuming that heat rejection occurs at an ambient temperature of 20 degrees Celsius, estimate the Carnot cycle thermal efficiency of a PWR (Pressurized Water Reactor) operating at an average heat addition temperatures T, of 168 °C. 2. List 5 Engineered Safety Features (ESFs of the PWR concept 2. Conbol colls, cantmnmont ok +cotbnaunt sprag) WPCT (hipresivd caoban? g, LPCT (tnw pressume calant weet)) esidbal bl ool gt e clamngpt