DECLASSIFIED BUSINESS -€0Hf'IBE lTE rf ' Authority NA D G6S 1 7 OAK RIDGE NATIONAL LABORATORY r- OPERATED BY UNION CARBIDE CORPORATION NUCLEAR DIVISION _ PO T OFFICE BOX X O t K RIDGE TEHHESSEE 37830 17 August 1977 Mr Robert E Upchurch Internationa l Security Affairs U S Energy Research and Jt lopment Administration Washingtc D C 20545 Dear Mr Upchurch We have studied thefuossibility of plutonium production in the 20 megawatt Safari Reactor ORR-swimming pool type located at the National Nuclear Research Center Pretoria South Africa Based on examination of quarterly reports on its operation from reactor startup on April 28 1965 through April 12 1977 other information and estimates we report the followi_n g 1 0 I Conclusions · ·1 1 ' L2 T'nere is no evidence that this research reactor has been used to produce plutonium We are convinced that it has not been used for plutonium production This reactor has a small annual production potential for plutonium most probably less than 1 0 kilogram plutonium per year 85 per cent on-stream factor a · r- Since the Safari is fueled with fully enriched uranium pluton production can be achieved only by placing natural uranilllll 238u in favorable locations in the 72 position fuel matrix If suctt were done there would be a noticeable increase in the number of fuel elements consumed per unit of energy produced and this would be different from the similar fuel burnup for the Oak Ridge Research Reactor ORR Safari burnup for similar fuel and fuel loadings correspond to ORR experience l 3 We are not aware of the existence of a radiochemical reprocessing plant in South Africa in which plutonium could be recovered even if it had been produced • But the capacity requirement is low of the order of several kilograms natural uranium per day so that recovery of plutonium at this low r te could be accomplished in specially equipped laboratory-scale hot cells BUSINES COHl IriEMTillt b- BUSINESS CmlFIBEH'FIA f' • 2 Mr Robert E Upchurch 17 August 19 77 1 4 The natural uranium that would be r equired would preferably be placed in the r eactor matrix as a blanket or dispersed optimally as natural uranium plates in certain fuel elements as uraniumaluminum alloy plates clad in aluminum We are unaware of the existence of facilities to fabricate plate-type fuel in South Africa 1 5 It is most improbable that this research reactor has been or would be in the future used for the production of plutonium for weapons use because of its very low production rate Assuming that the minimum quantity o f plutonium required for one nuclear device is of the order of 10 kilograms then ten to twenty years would be required to produce plutonium for one device in the Safari ·surely_aEsurd 1 6 The United States has supplied 104 2 kilograms total uranium or 94 8 kilograms of uranium-235 to fuel this reactor From our accounting the reactor has produced about 24 218 megawatt days of heat which consumed 30 685 grams of uranium-235 If an average of 35 per cent of uranium-235 in each fuel element was consumed then 87 670 grams have been both burned or committed to ·spent fuel This leaves an inventory 0£ p_e ps 36 or rom e fuel elements as a minimi nn 7 kilograms uranium-235 or assuming 40 per cent burnup perhaps 90 elements 18 kilograms uraniu -235 This supply of -fuel is normal it is inspected we think under a -United States bilateral by the IAEA inspectors We have no concern about the fuel inven tory_ a s a t e t · __ a u r c e on '- ' o _ _ i_ si s i i - le uranium-2 35 for nuclear device fabrication 2 0 Supporting Information and Analysis 2 1 The enriched uranium supplied for fueling this reactor was supplied by the United States and perhaps Great Britain Fuel elements of the 19 plate MTR-type have been fabricated by various U S contractors most recent of which was U S Nuclear now defunct Early on some fuel fabrication using U S -supplied uranium may have been done in Great Britain From records in the Oak Ridge Operations OffiGe E·RDA we learned that the following quantities of uranium have been provided as f uel for the Safari through 1975 no later shipments Total uranium Containing uranii nn-235 104 200 kilograms 94 823 kilograms V ·auSINESS eOHPIOEU'i'IAr - DECLASSIFIED Authority t l DG6S 1 7 · I' - • BUSINESS- QOHFIBEM'l'IAeb Mr Robert E Upchurch 2 2 17 August 1977 3 From quarterly reports the following approximate operating history has been derived Nominal Power Level calendar Period 4 26 65 to 9 30 65 Megawatt Hours in Period Start-up 10 1 65 to 3 1 68 2 045 5 Mw 8 829 2 1 69 to 12 31 71 10 Mw 93 196 1 1 72 to 4 12 77 20 Mw 477 169 Total ••••••••••••• 581 239 or 24 220 Mwd Note 1 Early period operation through 3 1 68 one shift per day five days per week 2 From 1973 average on-stream time was about 55% Currently reactor is on two shifts per day five days per week schedule 2 3 The Safari core contains from 26 to 30 fuel elements six control rods 21 beryllium reflector pieces and aluminum filler pieces t fill 72 lattice positions The fuel e lements currently contain 200 grams uraniu - 235 initially and are burned down to about 120 grams at discharge 40 per cent burnup At 20 Mw power level the av rage thepnal flux in the fuel is 3 between 8 x 1013 and 9 x 101 n crn2-sec slightly higher in the moderator positions about 1014 n cm 2- sec The rate of production of plutonium depends on the neutron flux and the amount of target uranium- 238 that can be exposed at first 1 approximation the rate of production is given by the following gram · 239 238 -15 Pu kg U per week 5 1 x 10 where flux in n cm 2 • a ' f sec Thus for uran um- 238 ex osed in reflector position where the flux might be about 1014 n cm sec the plutonium production would be about 0 5 gram kilogram uranium-238 per full power week or 0 0036 gram kilogram uranium-238 uranium per megawatt day 2 4 In reference F T Binford suggests three possibilities for exposing natural uranium in the ORR-type l attice His calculations are approximate and ·i' iot optimized but are accurate enough for this exercise The three loading possibilities are t r' DECLASSIFIED Authority N'AIDGGS 1 7 BUSINESS-eQN1 IBE l1'U BUSINESS _ • 4 Mr Robe rt E Upchurch 17 August 1977 1 Uranium-238 could be introduced into the reactor in the fonn of fuel plates interspers ed among the highly enriched plates As much as 350 grams per plate could be introduced in this way The exact number of such plates which could be used cannot b e easily determined since the introduction of the uranium-238 which is a mild neutron poison will have an effect on the core loading and result in a lowering of the flux However if it is assumed that 15 per cent of the plates could carry uranium-238 then the total target loading becomes 28 kilograms and the production rate would be about 14_ grams per week 2 Flux traps which effectively increase the local neutron flux could be used If dedicated to this purpose the Safari core· could probably support four such traps in which the thermal neutron flux could be as high as 5 x 1014 n cm2sec The traps could utilize light water or perhaps heavy water and contain as much as four kilograms uranium-238 The production rate by this method would be about 40 grams per week 3 By using lower enrichment uraniurn-235 say 20 per cent a fuel ·loading of 5 5 kilograms would contain 27 5 kilograms of uranium-238 and the production rate would be about 12 grams per week of· these methods the first would be the simplest but would require t e capabi l i ty to fabrica t e fuel plates having virtually 100 per c e nt na tural uranium in t he cores In a ny cas e the technology exis t s to fabricate fue l cores containing up to 50 per cent uranium for this purpos e The second method would require dedication of the reactor or a larg portion of it to plutonium production Of cours e more refined calculations would be required to support the accuracy of our estimate I The third method has the distinct disadvantage that the sewa rations process would involve handling very large quantities of ission products In the other two cases the associated fission product inventories in the target are considerably sma ller 2 5 Based on the foregoing we estimate that as a practical matter it is not unre asonable to suppose that something of the order of t e n grams to twenty grams per we ek o f plutonium could b e produce d in a research reactor such as the Safari V 1 Memorandum of August 17 1977 F T Binford to F L Culler subject Pu Production in Safari DECLASSIFIED Authority j t D GGS 1-7 BUSINESS -e0Hl' IDEIUIM BUSINES 3--€0HFIBIJU' l '1Air- Mr Robert E Upchurch 3 0 17 August 1977 5 Hypothetical Estimates of Past and Possible Future Production in Safari The following table sums up the hypothetically possible past production and similarly future potential for several loadings and two power levels These are hypothetical only We einphatically do not believe tllat plutonium has been or will be produced in the Safari Hypothetical Plutonium Production for P·u Loading 1 Easiest Pu Loading 2 Difficult Since startup 1966-1977 Actual burnup 24 220 Mwd 2 44 kg 6· 9 kg Maximum Yearly Production Potential 20 Mw 85% on-stream 0 6 kg year 1 7 kg year 4 0 References Attached is a description of the Safari reactor Attachment A If you need details of the operation of this reactor we have quarterly reports on file at the Oak Ridge National Laboratory Questions should be directed to Frank T Binford Operations Division who prepared information contained in this letter Very truly yours $Jx I a l1 Floyd L Culler Jr Deputy Director FLC vmw ' I Attachment A cc F T Binford J A Cox J A Lenhard H Postr ia Official Files DECLASSIFIED Authority _ t - RC INESS €0t f £15ELQIIAL IND GGS L A nvt t-lprodllcetf @ f 2 3 77 DECLASSIFIED To F - Culler 8 17 77 J From W K Bensen ERDA ISA Authority NlvOGG g 1 _7 mm ftt Uy 90% e llaf t toter imderat o f md COQI d r Pi t 1 e fJt eeed _20 £ therm J t In ftlally G 67 et eooli-ae - · -- --· - - Nt lonal _clear C- cnt er Pel J rl M• Fl ia ll -South Ai - - - r uc l l f l 1t a stfaet Cc dlding iµ•euc etc l f ettt in s - '- --- ·· · 6 · - # -• - - - --- - 7 gy Ci£ t i c a deal npe ratittS em e amsf '1' t s af 22 fD ttl elt Cll »t- J S cumt t nl Dld 2% r e f i 23 f Hl«r p i re sdu a fe of f fen at 2n t 'fi 1 - _H- s ¥# 'i feck rrn-r ·a J ' • 4 at w o-235 1 c o n tt t l CCil a inf g JJS c f tr-i35' laadad E 6 is fat a af l yezr iit Offl t 4 tnttl of 10 simt t is-s tie r e - aa a 4- o tt iQ rzf fua al xreurs -- T ' '° e m 1 m- -- f is ± aiO g r g j t 1 1- i ¢etl l g i to tsl of ll l 45 of 'U-•235 i 1113 494 Kg Wt mWL at S 0% » - -·· -· f t mt -D t -r t y nf Vo V- • • ' T e $t 21d tx pe ri 'i-1 Dttl React ors g s • 1' 1 Hsbe i liy A Attachment A to August 17 1977 1 e tter f rom P L · Culler to R E Upchurch upp li d by S cn t4 Afri c u ' ' DECLASSIFIED NAID GGg 1__7 Authority SOUTH AFRl A SAFARI - SAFARl - 1 RESEARCH REACTOR PURPOSE Research and Test f DATE OF INFORMATION January 1963 GENE R AL 1 Reacto r typ Tank type fully enrich ed 90% uranium light w ler moderated and cooled beryllium enected 5 O wner and operato r 2 Nominal r eactor Oesign 20 MW thermal Initially 6 67 MW cooling capacity 6 Designer and builder Basic resea ch engineering tests isotope produc• 7 Present status construction power 3 Purpos tion fuel element development South African Atomic Energy Board l'I Reactor Allis-Chalmers Manufacturing Co Buildings process equipment etc Atomic Ene gy Board and South African firms schedule Under construction Stzrt of construction 1961 Reac tor c ritical 1964 N ational Nuclear Research Center Pelihdaba near Pretoria South Africa 4 Locat ion REACTOR PHYS I CS The mal Lifetime initial 6 9 x iO -J sec m ean app ox 10- 4 sec 6 Neutron energy and lifetime Calculated 2 07 f •0 77 k • 1 59 L1 • 3 86 cm 9 Core parameters t • The mal av Th ermal max - 6 67 MW 5 0 X1 0ll 1 3x 101• 20MW 1 8x 10 14 4 0 1 014 1 0 p 1 0 k 0 fi 13 cold clean 61 0 cm Bl a 54 4 m-l Thormal l eakage factor Cr 978 F tst l eaka e factor 0 718 off u l C end of i o ·e life r' - Calculated in n cm sec 10 Neutron fl ux 6 67 MW Max built in cold clean 13 3% 11 Reactivity balance To compensate for t empcratu e Xe and Sm butnup eli pe iments operation 20MW 14 5% 0 76 4 9 l j 2 e2% 3 98% 0 81% 0 76% 5 32% 2 77% 4 85% 0 81 % CORE 1 8 Average power Pa allelepip d max 27 5 25 5 in 24 in high cypical operating core T-sht ped 16 x 21 in • 24 in 12 Shape and dimensions 6 67 MW 68 kW litre 20 MW 204 kW l11re d ensity i n core high 19 Burnup 13 No of channels subassembl ies I Grid plate with 9 y Min 20% of r ssionable mateti tl 20 Fuel l oading 8 posi ions After reactor shut -down cen1tal hatch on tank can be removed and fuel elements will be chanQed manually u nder water by means of long handiing tool s and unloading typical ope ating core consis1S of 22 fuel clements 5 conuol rod olements 22 beryllium reflector elements 23 aluminium filler pieces or eli pe iments I I II II 21 Irrad iated fuel Rcc ta11pular 1 4 Lattice Storage room for irradiated fuel critically afe racks in the pools storage P1tcn 3 035 x 3 189 in elements in I I 22 ModtHator uu 1 5 Critical mass Calculated 1 521 kg 16 Core loading at Calculated 6 67 MW 3 604 g U ' 20 MW 3 357 kg rated power 17 A erapt specific power 10 fuel - u light water temperature 120-131 ° F fully Be 1cllected 6 67 MW 1850 kW kg UH 20 MW 5950 kW kg U' 23 Blanket gas None - FUEL ELEMENT ' 24 Form an d composition MTR-type flat plates Mc 11 dimensions 0 020 x 2A92 in • 23 625 in lon9 P1a1e o ver 111 0 050 x 2 867 in 24 625 on long Enrichment 90% alloyed w11h aluminium I I 25 Cladding J 26 Subasscmblies - 0 015 in type 1 100 aluminium tlloy - 119 pdtallel ol tt forrning l utl ciernent n control rod eff nenis • Plate I Overall cfim£ -o i ion ot fuci cl' munl 3 l SS '36 375 1 lor p 3 032 i -i ---- a ----7Lu'1 --r · - - -·- · · -l Lr- r 'i r - -----0----- F - T- - -- - E t D f D ' - 1----- -- --0 -- 0 ' e -z--ZL L J · j U 1 -- ____jTi ' -f 1 I I 36 75 in 1' 625 in I • - J FUEL ELEMENT SCCTION A-4 F I I ___ _9 ' ' __j 0 0 I l fl Sin I 19 It II in I 14tUit'I 11 ll in 5 ti I 1 l · S ·4 ij '• OCCUDlfO 8Y FUE £l -'E'Nr ·1 lI I I ' DECLASSIFIED HORIZONTAL IAEA- R 5oa1ch R - SAFAR I - 1 SECTION REACTOR 96 SA FAR I - 1 Authority N vD 6G 1 _7 2 DECLASSIFIED Authority 1 1 D 6 68 7 0 REACTOR I 65 25 n od Yf SS L - - L· · • RESEARCH C AAHf VERTICAL SECTION REACTOR SAFARI - 1 FACILITIES INlIT ' - z H eat t r ansfer ore a - For core of 22 fuel elemants and 5 control rod 32 Coolan t mass flow rata Al 6 67 MW 3000 gpm 1 5 x 106 lb hr Al 20MW 12 000gpm 6 x 1o• lb hr In BTU ft' hr Av Mait 33 Coolant pressu r es Al 20 MW lnlel 120° F 24 psig Oullet 131 5 ° F 12 psig clements hair-way oui 370 ft 34 37 m' 28 Heat flux I I C O RE H EAT TR A N S F ER ---v 6 67 MW 54000 123000 20 MW 166000 380000 temperatur es I 29 F u e l el ment 34 H o t channel Mox cladding design 268° F al 3000 gp n a 'd 6 67 MW temperatures Film dtop factors Coolant rise 1 98 1 29 I - 30 H eat tran sfe r At 6 67 MW 1830 BTU h' hr °F Al 20 MW 5500 8TU ft2 hr °F coeffici nt I 3·1 Coo ldnt flo w a rea velocity T otal flow area Av velocity 6 67 MW 1 32 ft2 5 2 ft sec 20 MW 1 28 rt 2 20 7 ft sec 35 Sh'ut- down h ea t remova l 1000 gpm pump driven from fail-safe po wer suppiy CONTRO L 36 Control reg u - ' total rod length 117 in • approx 3 x 3 in rods ate d riven from below the reactor ll k ' To1al worth of 5 rods 26 % T - Worth of single regula1ing rod 5% 39 Sensitivity of a u to control for 6 67 MW co e 40 T emperature k coefficients Ma rod speed a pprox 0 083 in sec I ± 0 55' of nominal power I Au1oma cic control limiced by interlocks to 0 5% k I 6k Av calcula1ed -2 37 x 10 - % T °C None I N'JVD G6 S 1 7 I Release time 0 07 sec rod drop time 0 3 sec Burn Jble I 4 1 poison DECLASSIFIED Authority Magnetic elease gravity fall mechanism section 24 in long fuel plales 15 pla1es per rod ' 38 Scram t ime 5 control rods ontt of t hem used as regulating rod Rod consists of two sections upper section of 3 2 in cadmium clad in aluminium lower lating and sa f e t y rods 42 Oth er con trol sa f t v shut- None down provisions i j ok 37 Reac t i•Jity Estimated ma 0 1 % T sec when 5 rods aro addi tion rate withdrawn simulraneously R E A TOR VESSEL OVERALL DIMENSION S Cylinder 14 ft 9 875 in high 5 f 3 75 in id mado of type 5052 aluminium wall 1hickness 0 75 in some parts 1 375 in - - - - - - - - - - --' Reactor tank is located in one of three pools approx 28 ft deep rP actor pool 22 ft 4 in long s101a9e pool 19 ft 11 in canal pool approx 13 ft internal w idth 10 It for all pools 4 3 Form material and dimensions 44 VVor ing d sign test pressures 'vVori ing pressure Design pressu o Test pressure 45 Reactor with 30 ps 36 p si 54 psi Overall dimensions of 3 pools approx 82 x 32 ft 28 ft high sh ielding REFLECTOR AND SH I ELDING 4 6 Reflec t o r Beryllium metal elements outer dimensions and shape similar to fuel elements 22 clements for 48 Shielding 6 6 7 MW core 37 elemenls for 20 MW coro 47 Radia tion l evels app x 4 ft light water 9 10 11 ft magnetite concrete density 3 5 Bottom app o 6 ft li9h1 wa1er 7 fl m agnetite concrote dens ty 3 5 Top 23 ft light wa1er I At 20 MW less lhan 0 75 mt hr outside concre10 shield less than 2 mr hr above pool CONTAINMEN T 49 Type a nd materia l Sides I Semi gas-light concreta s1ruc1ure approx 1 1 O• 90 ft 100 ft high 50 S u rroundings Working pressure 0 05 in H 1 0 below atmospheric Test prossure 0 05 in H20 below a nd above atmospheric I The Na1ional Nuclear Research Centet is si1ua1ed 17 miles from tho nearest large city in a spa sely populated area Terrain of open country with low hills and v 1lleys river approx 1 mile from the site COST EST I MATE 51 React o r and building 2 Support facilities $4 5 million including associated laboratories and Assembly Hall SJ Operating costs Not availa ble See under 51 54 Staff require- Estimated 27 operating st ilf excluding maintenance and experiment installation IAEA-Rcsearch R - SAFARI - 1 m ents 98 4 ' ' 'i I • ·R ES E A RCH FAC ILI T I E S ' Desi gnation N o Posi t ion U se fu l d imensions in ' i' N e utro n flu x n cm 2 sec R em arks ' a t 20 MW I H orizontal beam tubes I i I I I I 4 1 2 H orizontal through tubes 2 3 7 d iam 1 X 10 14 on flat side of tank 1 ••oe facility 1 4 60 dia m 5 X 101l may be converted to thermal column Hydroulic tube 1 5 1 5 od Pnt umatic tubes 2 6 1 5 od 1 x 1 Oll Ve rtical tube in reflecto r 1 7 3 ·diam 1 2 lq core positions variable 8 max 3 i Channels in B lements I Pool s ide facility t Ory gamma facility I Ho t cell i 10 9 1 I - 1 0 10 diem 7 diam 1 5 x 10 1 S x 10 14 in c o e position 1 6x 10 X 1012 3 x3 max 2 x 1014 6x6 max 4 x 101 4 2 diam max 2 x 1 01 32 x 48 1 in reflector position access holes so that loops may b install access hoies so that loops may be ins tall tor isotope X 1014 production on flat side of tank 24 x24 in storage pool 120 x 144 x 1 32 2 s ub-cells abo ve cpnal pool ' DECLASSIFIED 'i Authority ¥ AID 6 S 1-Z I ' '• j I l I I I I ' i ·c _ I I I ' __J i I I I - ·- r · - ' 55 H'e a exch ngers I I 56 Coo f ant iosses punfi cation _ I 57 Oecompo i t ion recombination I I HorizontJI tube and shell type Ont inst illed for 6 67 MW throe required for 20 MW Capacity Pdr o changer 22 8 ' 100 BTU hr Purification by filters and a 80 00m rlttmin6ralise 50gpm deg tsifier venting products to off-gas system 58 Cooling system safe t y 59 Fuel fail ure dotection - I Opening tank to pool wtiter for C' dt convection coolinn sp y system ebov 1 car' supplied from proccs - water arm- syphon loop in primary circuit I Monitoring for fission products in p imary coolant I I DECLASSIFIED o f docom poi ition Authority t lvD 2 6S 1 Z - II - ll f • 1K1 COl U- 0 I 1 1 l l_ l l r i 'I I 1 L-----L-- - - -- -- - - - -- ---------'''° ' ' ' -''-- ' - __________ _______________ FLO W DI AGRAM REACTOR SAFARI - I DIBLIOGnAPHY REMARK S 1 Nuc lonr Powur Jo11unrv 1003 I 't IJli I 1 L I I I I IAL n lr 11 - l 1PAnl 1 100 0