Document 71EMRnjjR2n99mgNZ1bbNxqv6

>1 II ir 'Vi-J Ca. U-iCJ., L. I LJ, Producers of refractor materials. 331 Fulwccd Road. Sheffield SIO 308. Telephone 0742 303921 (10 lines). Telex S442S degiewed Office. Pagtstsred in England. Mo. IS3AM VAT Peg, No. 172 3715 53 ATN/MT Air Products & Chemicals Inc. , Escambia Plant, P.O.Box 467, Pensacola, Florida 32592, U.S.A. 8th July, 1980. Dear Sirs, Re: Proposed use of PH/NUA21 Catalyst in your Methanol Plant Reformer We confirm that Pickford Holland & Co.Ltd. will accept the return, of all normal radioactive waste (contaminated coveralls, radioactive dust, used catalyst etc.) which arise during the loading/unioadlng of our PH/NUA21 catalyst, to the United Kingdom for disposal at an approved dumping site within the United Kingdom. All costs to be borne by client. The regulation packing requirements and current disposal costs are outlined in the attached publication. Yours faithfully, . for PICKFORD HOLLAND & CO. LTD. A.J.NORMAN Technical Sales Manager, Catalyst Dept. Encs. A member of the Dyson Group of Companies AP00026867 Pr-oducars of refractory motariala. 3et Fulwood Road. Sheffield 510 3GB. Telephone 0742 303921 [10 linei). Tele* 54426 Sagmarad Offiee. Ragntarad in England.No.126*14 VAT Rag.No. 172 3715 69 Disposal of used NUA21 plus other radioactive waste 1. Regulations The regulations for shipping used NUA21 are as strict as those for shipping new catalyst and must be fully complied with. The requirements are as follows. The catalyst must be loaded in good, rust free steel drums conforming to the International Atomic Energy Authority (IATA) Transport Regulations for Type *A' packages. In our experience the thickness of the steel including the lid should be not less than 0.048 inches (1.2mm). Tne catalyst should be packed inside a polythene liner inside the drum or in a nunber of smaller polythene bags. The radiation requirements are that the dose rate measurable on the outside, of the steel drums (V radiation) must not exceed 0.5mRem/hour and the removable surface contamination on the drums must be less than -3 2 lO ^Ci/cm . TO reduce transport costs the catalyst should be packed in drums of optimum size 23 inches dia <58.5 cos) by 33.1/2 inches high (85 cms). Four drums should be strapped on a wooden pallet, size 44 x 44 inches (112 x 112 cms), which will fit side by side in container vessels. 2. Method of disposal. Pickford Holland have an arrangement with British Nuclear Fuels Ltd. for the disposal of spent NUA21 plus other radioactive waste arising from the charging and discharging of the catalyst in a Client's reformer tubes. The arrangements call for the following instructions to be carried out. Upon arrival at a CJ.K. port, the containers holding the spent NUA21 plus waste material must be unloaded for onward transmission via road transport to Pickford Holland works at West Hunwick, Co.Durham. at Pickford Holland works. A BNFL Inspector will inspect the drums A member of the Dyson Group of Compenies continued AP00026868 Disposal of used KUR21 plus other radioactive waste (COnt* (3) . 1 f After acceptance for dumping, the spent catalyst plus vaste material win be taken by a special BNFL lorry from Pickford Holland works to the approved dumping Sl a 3. Cost, of disposal. (a) Provision of polythene bags, druES and pallets; Client's liability. (b) Transport from Client's site to FOB port of Client's choice; Client's liabllit: (c) Shipping costs from port of Client's choice to U.K.port; Client's liability. (d) Unloading from containers on to road lorries and transport to West Hunwick; 60.00 per tonne. (e) Inspection at West Hunwick and transport to duroing site; 19.625 per tonne. (f) Dumping charge; 12.25 per tonne. Sub Total 4X^37^oertonne. (g) Pickford Holland handling charge; 150 or 10% of the subtotal, whichever is the greater. Pickford Holland have no control over the prices shown in items (d) , (e) and (f) which are therefore given without guarantee. AP00026869 PRECAUTIONS TO BE TAKEN WHEN STORING, HANDLING AND USING NICKEL URANIUM STEAM REFORMING CATALYSTS by M.D. Hill and A,D. l.'rixon Pickford, Holland and Co.Ltd. Contract No. 6/1017 National Radiological Protection Hoard Harwell, * Didcot, Oxon. Oxll ORQ June, 1-375 ... AP00026870 1 Abstract This report has been prepared by the national Radiological Protection Board Tor Pickford, Holland and Co. Ltd. The potential hazards associated vrith the use of nickel uranium steam reforming catalysts, which are slightly radioactive, have been assessed in the light of the recommendations of the 'International Commission on Radiological Protection. It is concluded that these catalysts can bo used safely provided some simple industrial hygiene procedures are followed. The most important of these procedures are the wearing of gloves when handling the catalyst and the use of techniques to reduce dust levels when loading and unloading reformer tubes. Special medical supervision of workers should not he necessary* v AP00026871  MAWfcU'A UiUUl.'iil X UX L-<X biX 1 jr i, Ui> C wi 4 i--^xT* UCJi.V wLU U^L.UXhU*4 x'^TT ic slightly radioactive. ]!ov;cvcr, the hazards associated with this material are negligible if simple precautions are taken to ensure good industrial hycicnc. Hie catalysts consist of uranium oxide, nickel oxide and a small amount of barium, supported on alumina. The main problem arising from their use is due to the dust produced during handling, and most of the precautions are therefore directed at reducing dust levels and hence intakes of dust. ' 2. RADIOLOGICAL' PROTECTION DATA 2.1 ' Properties of Depleted Uranium Naturally occurring uranium consists of three isotopes: uraniura-238 (99*3^) uranium-235 (0.7?o) and uranium-23U (0.006$o). Depleted uranium has a lower activity than natural uranium since part of the uranium-235 (and some of the uranium-23I1) has been artificially removed, typically depleted uranium contains 0. uranium-235- All three isotopes of uranium emitoC-radiation and produce daughter ^isotopes which art also radioactive, emitting i><., {S raid Y -radiation. These ..three types of radiation will therefore be emitted by depleted uranium catalysts. ' Alpha-radiation has a very short range and is stopped by, for example a few centimetres of air or the dead layer of the chin. External to the body it therefore presents no hazard but internally it is the radiation of principal concern. Since the catalyst is in insoluble form the organs of the body chiefly affected by eating or breathing in the catalyst will be the gastro-intestinal tract and the lung respectively. Eeta-radiation has a somewhat longer range and if the catalyst is handled directly this can cause external irradiation of the skin and hands. However, any normal form, of' containment of the catalyst will eliminate this since, for example, 1.1; mm of steel is sufficient to completely stop the radiation. Gamma-radiation is much more penetrating than < or -radiation Put the intensity decreases rapidly with distance. In view of its penetrating nature it can cause irradiation of the whole body and is the only radiation of interest when the catalyst is contained in storage drums or reformer tubes. 2.2 Basi.c Standards The basic standards of radiological protection arc those of the International Commission on Radiological Protection, TCnP, who have laid down maximum permissible levels of radiation exposure'^- These levels have been accepted internationally and those vhich are relevant to this assessment are given in Table 1. l m rt AP00026872 ICRP Kruunun Pcrnlssiblc Ibsen for ' Occunationallv ky-ooscd Persons Organ Vhole Body Skin Hands lung GI tract Maximum Permissible Poses * rsm 5 30 75 15 .. .15 In addition ICRP recommend that workers who might receive more than -fn of the maximum permissible annual dose should he subject to special health supervision and personal monitoring. Bor short term or intermittent exposures ICRP consider that up to one- half of the annual dose limit nay be received in any period of a quarter of a year. , 2,3 Derived Standards The basic standards of ICRP.have been used as a basis for derived standards more suitable for the working environment. Since uranium catalyst can cause both internal irradiation (principally from its <rC. -emission) and eatomal irradiation (iron ita /3 end f -emission) the derived standards for these will be considered separately. 2.3.1 Internal irradiation This v/ould arise following inadvertent ingestion or inhalation of the catalyst. The maximum permissible concentrations of natural uranium (insoluble form) in v/ater and air for continuous occupational exposure (kO h per weeIt, 50 weeks per year) and the maximum quarterly and. daily intakes obtained from ICRP data are given in Table 2\2). AP00026873 VjJ ro <n tn --i. X ov*1> pMM ;o P MQCT* OHH> O o< oHpPoBrt* MP Q O3O o Ho3rh PHrh* o o ocd C} H- o w3 Pc*- BH- WP HO- cf H 3WO tPP-* O_Sty. Of--->^ S o oo 5 tHo S oVjJ>*r0"t*>4 UIJ + M $<7Tt < O ro o oo M If g B *1 d' UlO O + p> 3* B UPP ' 2" H 6o WO 6 K p* S' ^ !* co c+> <T> AP00026874 KaxlGMsi P o m is s ib le C o n c e n tra tio n s , Q u a rte rly and T a lly Intakes f o r N a tu ra l P raniua (in s o lu b le fo ra ) . Ho data have been published by, ICHP for depleted uranium, but eiv.ee its radioactivity is less than that of natural uranium, somewhat higher maxistun pcraicr.ible concentrations in mass terns (pc cm"3 or pc ru~3) may be allowed. However, the values in Table 2 for natural uranium will bo used here. . Although the values in. Table 2 arc only for drinking water, the maximum permissible quarterly and daily intakes for water can be applied generally to all processes of ingestion e.g. eating, transfer from contaminated hands to mouth. To keep intakes from those processes within safe limits a maximum skin contamination level of 10"5 nCi cm-2 is allowed for uranium in the D.X.* ' 2.3-2 External irradiation Based on a normal working habit of L;0 hour s/week and $0 Y/eeks/ycar, the values in Table 1 can be used to calculate derived standards for continuous occupational exposure. Fpr whole body exposure from ? -radiation, the Unit will be 2.5 nrera h_1 and .pA of the limit, 0.75 nrem h--* . This means in practice that only employees working for appreciable periods of time in areas where the doco rate is greattr than 0.75 urem h-"1 Y/ill require iho special health supervision mentioned in section 2. In a similar way for exposure of the hands from p> -radiation the limit will be 1*0 nren h"'i and of t-he limit, 12 mren h-1. Those Yaluos will apply to continuous handling of uranium. To keep the (3 -radiation dose rats to I4O men h""' surface contamination, in controlled access areas is limitpd to 10"3 /uCi cm"2 in the U.K. for * urani'am. This is rediiced to 10"^ ^iCi cm-2 for general access areas.* ' ASSESSHETT OF POTEViTIiL HAZARDS FROM DEPLETED DTJUTIDT-I CATALYST It will be assumed that IQJa by weight of the catalyst consists of depleted uranium. 3.1 Storm" Here there is no possibility of intake of the catalyst into the body and only the external radiation need be considered. As already shown the cxC. and ft -radiation will be absorbed by the drums in which the catalyst is contained and only the external 'ft -radiation need therefore be considered. The theoretical Y -dose rate at the surface of depleted uranium is about U mrem h"^'*,^I v;hilc measurements on a catalyst containing 7;a uranium slioY/od a dose rate of 1 inrem h~^ at the surface of the uncovered catalyst and 0.2 mrem h~` at the smrface of a steel drum containing 225 kg catalyst. . The dose rate falls off rapidly with increasing distance and at 1 m is indistinguishable from natural background radiation. It is therefore inconceivable even with catalysts containing 15/J depleted uranium that tho ~-A derived standard of 0.75 mrem h"1 will ever be exceeded. *Limits for skin and surface contamination vary from one country to another (5) U.X. limits have been quoted but catalyst uoerr; should consult* the regulations of their coimtry on this point. AP00026875 3,2 Operation of Refornc.r Tubes Hero, as in the cws oC storage there is no possibility of internal irradiation. The external radiation hazard is also negligible since the vails of the reformer tubes are thich enough (typically 1.2-1,$ cn) to reduce the dose rate at the surface of the tubes to a level indistinguishable from, background radiation. 3.3 Handlin'? Handling of the catalyst during the leading and unloading of reformer tubes my give rise to dust which will subsequently be breathed in or ingested. External irradiation, particularly of the hands .and skin needs to be considered. 3*3.1 Internal irradiation Assuming that only catalyst metals Give rise to dust the figures given in Table 2 for the quantities in ug and pg nr3 should be multiplied by three for a catalyst containing 20;i total motels and 7>o uranium. This will represent the worst ca.se. (a) Inhalation of dust The maximum permissible concentration of catalyst in air is therefore about G.rJl, ng n~3 for continuous occupational exposure. A visibly dusty atmosphere would contain about 2 Eg n~3. Although during handling operations this value nay be exceeded for short periods of tine,..in view of the intermittent nature of the operations, it is unlikely that the maximum permissible daily intake will be . exceeded and certainly for the long-term average conditions d030S w ill be. well below the lu limit. (b) Inpostion of chist As already stated ingestion of dust could arise via-transfer of catalyst on hands to mouth or to foodstuffs and it was from a consideration of this that the derived standard of 10~5 ^.Ci cm-^ wan obtained for shin contamination. Of course, if no precautions at all were taken during handling of the catalyst, contamination levels of hands could exceed this level but use of very elementary precautions such as wearing of gloves and washing of hands before eating will virtually eliminate any possible intake from this source. 3*3*2 External irradiation The principal concern hero is with the possibility of j3 -irradiation of the hands and skin. Some Y -irradiation will also occur but this is much smaller. For a catalyst containing 1C^ depleted,uranium .the theoretical surface p -dose rate is about 20 wren h_1 , vrhile measurements on a catalyst containing 7/6 uranium gave a value of 8.7 rorem h~1. Handling of the catalyst will normally bo infrequent but even assuming a fi --surface dose rate of 20 mrom h-^, a worker could spend 1000 hours each year handling bulk quantities of the catalyst with his bare hands without exceeding of the maximum permissible annual 1.Vdose. Wearing PVC gloves (thickness sa) would reduce tho dose received by about 60JoUw and would also prevent contamination of the hands. Tho presence of nickel in tho catalysts also makes protection of Dip skin and *\ AP00026876  It in provable that during the handling procedure zone duct will be cpreacl into surrounding areas. Keasurements have shown that on visibly dusty surfaces the derived limit of 10~^^uCl cm-2 for inactive areas tcay occasionally be exceeded. However, again it must be emphasised that this limit is for the continuous situation and provided elementary cleaning is undertaken. following the handling there will not be any problem. ]. ?nOCErT7l~5-Ah~D PRECAUTIOHS The main hazard associated with those catalysts arises from the dust produced during operations such as the loading and unloading of reformer tubes. Some simple precautions will reduce the ricks of inhalation and of contamination of skin and working surfaces to a minimum. The presence or absence of visible dust is a Good indication of the standard of industrial hygiene. U1 Personnel Protection Persons engaged in handling the^catalyst should be given instructions on safety procedures and informed of the possible hazards. The following precautions apply to any potentially dusty operations, in particular the loading and unloading of reformer tubes. (a) Clothing Persons handling the catalyst should wear gloves (stout rubber or PYC), one-pieco overalls, boots and helmets. Sor;a ~fora of respiratory protection is desirable although not strictly necessary: either goggles and a clust respirator, or an-air-line heed is suitable. Overalls and other protective equipment should be removed on leaving the working area. ,!Ehe cleaning of clothing and equipment is dealt with under U-5* (b) Eating, drinking etc. Eating, drinking, smoking and the handling of consumable items should ba prohibited in working areas, as they are in any places where materials of similar toxicity are handled. (c) Washing Workers should wash their hands before meal breaks and at the end of the day. More extensive washing nay be considered necessary, depending Qjjfeiihe levels of dust encountered. It is essential to remove all traecqjgS& dust from the skin. Separate washing faeil i ti vr. rh.-mld. be reservoCfor workers during catalyst handling onpratians. They can ba releasee fog general use after decontamination and nonioa?iu/r. (d) Cuts, abracions etc. /^Any cuts, abrasions or wounds which' have been exposed to contamination^ should bo treated by a medical practitioner. Existing cuts or breaks in /the skin should be covered before starting work to prevent entry of du:;t Ipr catalyst. ---------- ------ (e) Handling time The time spent handling'the catalyst should be kept to a minimum and gloves should always be worn. AP00026877 Special diecl supervision of workers and the wearing of film badges or other personal dosimeters is normally unncccssar''. In the TJ.K. vorkcrc with the catalyst need not bn 'formally classified r.a radiation workers providing they are employed in accordance with a scheme of work approved by II.K. Chief Inspector of Factories, 1+.2 Store or; The catalyst should be kept in a separate store or in a specially designated area of the main store. Hie storage area should be marked with the radioactivity symbol end access to it should be limited. The catalyst drums should be sealed when not in use. Any spillage should be dealt with in a sailiar manner to that described .below for loading and unloading reformer tubes. An account should bo kept of the issues and receipts of catalyst. U.3 Precautions during Operation of the reformer Tubes No precautions are necessary'during the operation of the reformer tubes. The walls of the tubes provide adequate shielding against external radiation. I4.lv Loadin': and Unloading of Catalyst from Nefomer (a) The working area should bo regarded as a controlled or active area and access to it should bo limited. (b) The working area should be covered with polythene sheets to facilitate collection cf dust and spilled catalyst. These can be cleaned with an industrial vacuum cleaner and hosed down after use. (e) The catalyst should be loaded and discharged fren the rcforr.sr tubes by a method which minimises the creation, of duct. For example, loading can be done by the sock or canister method and unloading by means of en industrial vacuum cleaner. <*> "Protection of the working area from draughts educes the inhalation. risk and prevents the spread of catalyst. (e) ! Tlis working area should be decontaminated and monitored before general access is allowed. The maxinr.ua permissible contamination level depends on the country concerned. If no such level exists the U.K, figure of 10"^ ^.Ci cn-^ is recommended. (f) The industrial vacuum cleaner uced for unloading reformer tubes and for collecting dust and spilled catalyst should exhaust to fresh air to avoid raising dust and its exhauster outlet should bo filtered. (g) Any dust or spillage collected should bo removed from the working area said disposed of as outlined below. lv5 Waste The waste arising from the use of nickel uranium catalysts is technically radioactive: waste and must be disposed of according to the legislation of the country concerned. Spent catalyst, dust and spilled catalyst axe all classed \ I I AP00026878 `as solid radioactive waste and should be stored in scaled drums pending diepos: Protective clothing ar.d equipment should be vacuumed to remove loose dust and monitored Tor contamination. If the levels arc sufficiently lov.* clothing can be laundered in the normal way, if not it should bo specially cleaned or" disposed of as solid waste, Disposable clothing and equipment must be treated as radio active waste. ' liquid wastes from cleaning operations are also technically radioactive waste but the activity levels will probably be low enough for them to bo disposed of to drain. This includes washings from cleaning protective equipment c.g. boots and helmets. At least for a period after reloading a reformer tube, condensate produced during the steam reforming process will contain some uranium. U.K. measurements have chovm that the concentration of uranium in tho condensate is likely to be small (of the order of 0.01 pg cn~3) and since dilution uith other non-radioactive waste liquors will probably occur, there should be no restriction on disposing of the condensate to drain. ` 5. COkCLUSIOITS 1. ITickel uranium steam reforming catalysts can be used safely providing some simple industrial hygiene procedures are ^followed. 2. The most important of these procedures are the wearing of gloves when handling the catalyst and the use of techniques intended to reduce dust levels when loading and unloading reformer tubes. 3. Ho special medical supervision of workers should be necessary- U. . Internationally accepted recommendations on maximum permissible radiation doses have been quoted but potential catalyst users are advisc-d to consult the legislation of their country on points of detail. 6. BiTr^gi'cn-rs" 1. ICRP Publication St Pcrgamon Press, Oxford I96S. '2. ICRP Publication 6, Pergason Press, Oxford 1962. 3. ACGHI (Threshold Limits Committee) 1971, documentation of Threshold Limits "Values (ACGHI, P.0. Box 1937* Cincinnati, Ohio i(5201, USA). I4. A review the Toxicology and Potential Hazards of Natural., Depleted and Enric^i Uranium. E.J. Bsnnslliclz TJICASA Pep ort AHSL (HP) K58 (1966). 5. Monitoring of Radioactive Contamination on Surfaces, IAEA Technical Reports Series Mo. 120 IAEA, Vienna, 1970. AP00026879 \ 'm** i 'Oi'--'lU'u;C:, S iVwiil " Grid loading of PH/NUk21 catalysts SI fcr UUVUI Siuy c?5 Ui FH/NUK 27 NUA21 is slightly radioactive as a result of its uranium oxide content. A frequently accepted definition of a radioactive substance is one that has a specific activity greater than 0-002 microCuries per gram. Pickford Holland uso only depleted uranium oxide which means that NUA21 is less radioactive than it would be if uranium oxide from natural uranium ore was used. The specific activities of and rad ration from NUA21 are as follows:- Specific activities Alpha 0-035 microCuries per gram of catalyst 1 Beta 0-0476 microCuries pergram of catalyst ' Gamma 0-00084 microCuries - MeV pergram of catalyst. Radiation measurements in millirads/hour Radiation measurements in millirads/hour Beta plus Gamma At catalyst surface 9-7 0-3 metres from surface 0-5 \ Gamma 1-0 0-1 The above data show that there is no radiation danger in handling NUA21 catalyst. Precautions are required to avoid operators ingesting or inhaling the catalyst or dust arising from it (c.g. during the sieving operation prior to loading the catalyst in the reformer tubes). Uranium is of a similar toxicity to nickel. Therefore the same son of precautions with NUA21 as with conventional nickel catalysts are required. It will also be necessary to satisfy local regulations regarding the use of radioactive materials. Our technical staff will be pleased to assist customers in meeting the regulations. A separate Assessment Report entitled 'Precautions to be taken when storing, handling and using Nickel-Urania Steam Reforming Catalysts' prepared for Pickford Holland by the National Radiological Protection Board in the UK is available. Catalyst loading and start-up instructions are also available. 1. Manufactured by Pickford. Holland & Co. Ltd., a company with almost a century of manufacturing experience in the field of high technology refractories. 2. Backed by the engineering, chemical engineering and gas manufacturing expertise of British Gas Corporation. 3. Manufactured only from carefully selected raw materials of the highest quality. 4. Manufactured to British Gas specifications to ensure consistent physical, mechanical and chemical properties. 5. NUA21 has a high initial activity, the approach to methane equilibrium usually being less than 10 *C 6. NUA21 maintains its high activity throughout its long working life. 7. NUA21 will reform a variety of hydrocarbon feed stocksfrom methane to hexane or, in certain cases, light naphthas without carbon deposition. 8. Feedstock composition may be altered on the run with no deviation from equilibrium product gas composition. 9. NUA21 will reform hydrocarbon feedstocks over a wide range of steam carbon ratios. 10. In the event of accidental carbon or sulphur deposition, NUA21 may be regenerated with no disintegration of the catalyst. The regenerated NUA21 wiil be capable of producing equilibrium gas at full design output. 11. NUA21 contains no sulphur. 12. NUA21 contains no volatile silica or alkalis and therefore will not produce problems downstream from the reformer. 13. The customer does not pay a process royalty. _______7.. . AP00026880 t-ri/ inui\2i cdtdlysf typical properties Chemical composition Ni U 69 - Alpha ai303 % % % % 11 7 1.6 substantially balance Physical and mechanical properties Density Ibs/cu. ft. kg/litre no vibration 84 1-34 full vibration 90 1-44 Crushing strength (side) k9 100 Permanent linear change % 24hrs at 1300'C <0:1 Abrasion loss < 2-5 British Gas Test (done on the support) TypicalSiies (Raschig ring form) height. mm (inches) .15(f) dia. mm (inches) 15(f) central hole dia, mm (inches) 6 (J) 15(5) 10(f) 6(i) Other sires can be manufactured to customers' specifications. AP00026881 i i,V>VV H i catalyst work? Typical properties of NUA21 are shown on page 11. An essential feature of NUA21 steam reforming catalyst is the presence of the nickel uranate compound NiU3010. On reduction of this compound with hydrogen or in some instances with feedstock, nickel crystallites and the uranium oxide U,0, are formed. The nickel crystallites measured along the 111 plane typically have a size of 220 to 270 A; this may be compared with 330 to 370 A also measured along the 111 plane of nickel crystallites produced from the reduction of nickel oxide (the compound present in conventional nickel catalysts before reduction) under similar conditions. The nickel crystallites produced from nickel uranate thus have a higher surface area than those produced from nickel oxide, hence the nickel urania catalyst has a higher activity than the conventional nickel catalyst. The uranium oxide U.0,separates the nickel crystallites from each other and thus prevents them from sintering. In this way the high activity of the catalyst is maintained. Becausethe high surface area of the nickel crystallites is independent of the surface area of the support material, a low surface area support of very high strength may be used. Thesupport used in the production of NUA21 is pure alpha alumina with a surface area controlled between 1.5 and 2.0 sq. metres/gram. The pore volume and pore size distribution are also carefully controlled. The result is a finished catalyst with a side crushing strength of 2 to 4 times that of conventional nickel catalysts. The very high strength enables the catalyst to withstand plant upsets that would cause conventional nickel catalysts to disintegrate. Uranium oxide. U,0,. being a non-stoichiometric oxide, favours the dissociation of steam; laboratory studies have indicated that in service the surface of NU A21 is fully saturated with adsorbed water. Thus carbon deposition, whether from catalytic and thermal cracking of the hydrocarbon feedstock or from the Bauduard reaction 2CO*COt 4- C, is much less likely to occur with NUA21 than with conventional nickel catalysts. Uranium oxide U,0, therefore performs 4 majorfunctions. 1. Its presence ensures that the nickel crystallites are smaller and therefore are of greater activity. 2. It prevents the nickel crystallites from sintering thus maintaining the high activity of the catalyst. 3. It permits the use of a very strong pure support material which enables the catalyst to withstand severe plant upsets. 4. It strongly inhibits carbon deposition thus enabling feedstocks uo to hexane or, in certain cases, higher hydrocarbons to be reformed. In addition NUA21 contains 1.6% barium in the form of barium carbonate. This compound also inhibits carbon deposition, the suggested reactions being:BaCO,+C=BaO -i- 2C0 BaO 4-CO,=BaCOj Barium carbonate and barium oxide are both solids of fow vapour pressure and do not therefore migrate down stream from the reformer. As a result N UA21 does not g ive rise to corrosion problems. AP00026882