ML19246B048
| ML19246B048 | |
| Person / Time | |
|---|---|
| Issue date: | 03/21/1973 |
| From: | NRC OFFICE OF STANDARDS DEVELOPMENT |
| To: | |
| References | |
| REGGD-03.007, REGGD-3.007, NUDOCS 7907110260 | |
| Download: ML19246B048 (2) | |
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3/21/73
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U.S. ATOMIC ENERGY COMMISSION REGU XORY GUBJE i
DIRECTORATE OF REQULATORY STANDARDS REGULATORY 'IUL)E 3.7 MONITORING OF COMBUSTIBLE GASES AND VAPORS IN PLUTONIUM PROCESSING AND FUEL FABRICATION PLANTS A. INTROOUCTION Combustible pses and vapors and their hmits of flammabihiy in vanous oxidizing atmospheres have been Each applicant for a hcense to possess and use studied by the Bureau of Mmes.' 2 Flamnubthty has special nuclear material in a plutonium processing and been found to be a function of the type of combustible fuel fabrication plant as defined in Q 70.4(r) of 10 CFR ps, oxidant concentration, temperat ure, humidity.
Part 70, "Special Nuclear Material," must fulfill the vessel c h a ra c t e r istics, and direction of flame provisions of 70.23,"Reruirements for the Approval propagation, a m ong other t hmgs. Withm the of Applications." Subparat sphs 70.23(a)(3) and (4) confinement barners of a p'utomum processing and fuel require that the applicant's proposed equipment and fabrication plan t, flammable mix tures m ust be facihties and poposed procedures be adequate to precluded, and therefore the maximum allowable protect health and to minimize danger to life or correntration of any combustible ps or vapor m a property. Where combustible gases and solvents are used mtxture should always be below the lower hmit of withm the confinement barriers of a plutonium flammabihty as given for that particular mixture.
processing and fuel fabrication plant, measures are needed to protect against the possibility of the Some common sources of combustible gases and formation of flammable mixtures with these gases and vapors that have led to fires and explosions withm vapors. The presence of such a flammable mixture confinement barners hne been (1) solvents or coolar.s withm the multiple confinement barners of the plant used in chemical processtng, surface finishmg. or could result in a fire or explo: ion which might breach equipment maintenance. (2) reducing atmospheres used one or more of the confinement barners and allow in c o n version and <mtenng furnaces. and (3) radioactive matenal to be dispersed within regions of the demmposition p ro d u cts formed dunng waste plant aad possibly the environs. This regulatory guide inemeration and chemical processing Measures have describes an acceptable program ior complying with the been d eveloped to prevent the cecurrence of Commissioa's regulations with reprd to protecting flammabihty conditwn :nd hase been based on one or more of the following concepts. (1) prohibitmg or apinst the possibibty of the formation of flammable
.mxtures with combustible pses and vapors.
restncttng the use of the combustible matenal.C) mert gas purgmg withm the confinement barners where B. OlSCUSSION combustible gases or vapors are expected, thus reducmg or ehmmatmg the ciudant content, or increasing the air Within a plutonium processing and fuel fabrication flow within these confinement barners. thus diluting the plant, a postulated fire or explosion is an accident that combustible coricentration below the lower hmit for can furmth sufficient energy for the release and dispersal flammabihty, and f3) estabhshing other procedural of radioactive matenal from the confinement barners to changes based upon the resuits of the accident the regions occupied by worlang personnel and, investigation.
depending upon the sev:rity of the accident, to the environs. Therefore, conditions that can lead to these
' Bureau of Mtnes Rulletin 503, "l2mits of Flammability of hatardous events must be precluded. One such event is Gase,s and Vapon." H. F. Coward and G. W. Jones the uncontrolled or undetected formation of a Bureau of Mines B u lle t in 627 Fla mm ability flammable mixture of a combustible gas nr vapor and an Charnt enstics of Com bu stible Ga ses and Vapors.'
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oxidant followed by its deflagration or detonation.
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USAEC REGULATORY OUIDES Comes of pahehad wises nov tw acts.asd tiv reouset ind>=tm the d've. ore deeute a> the US. Atomac E aeryv Commiso on. wesh.netoa. DC. 2tX>46 Roguastory Guedes are resued to esecribe end nwhe e=eeletNo to the putg e A rtent ica Director of Repletory sterwierde Commente eruf suggesteoas for not hode
__ to the AEC Replenery etett of inwemmeatg spec #f e parts of inorownware in etwee pedes are encoureyed and should to esat to the secre'ery the Commeosa's repent.one, to doeiassee tecesasauen used try the in of the Comraiemen. Us. Atomic E ne yv Commes.on w on.ngt oa D C. 2o64s e=e*ustM apeshe prat >aeme or postuteted eacneman. or to povede p to Atteatica Chet. Putd.c Proceedage sis" essWeesafe Regunstory Guedse ere act eutusfitutes for regutettone endl compitence aut*h thorn e act WW3eered. MetM and enduthoes gef9ergag from those set out en The p, des are usued in the fosto q tea tFomj dew.saone the paedse speel be aosoptgees of they prgweres e tese for the firepeny rogueeste to et e sosnaease or sene. nuance of a permn er Ecease try the Comneesson.
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- 3. Fuese arid Meter *ete IeCs..t.ee B Oe6 epe..cas:Hoo.tr; Patened peadne edit to rereced permeceny. es appropwee. so accommodsee e E aviroamsates and sit,ag 9
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While tha arrangement has for the most part been abnormal conditions, the formation of a flammable or e f fective in preventing the recurrence of fires and explosive mixture within the confinement barrien explosions for specific processes within an individual should be precluded by estabitshing suitable process facihty, such procedures usualty have been initiated paisir.eters and plant operating procedures.
and/or err.phasized only after an accident and may suffer 3.
Assurance ' hat the established processmh and with ture from relaxation of vigilance, process modifications, and the formation of unexpected
>Perating procedures are maintaining safe conditions combustible products. The monitor:ng and alarm system should be provided by suitaL4e contmuous momtcting for combustible cases and vapors discuned in this systems appropriately placed wittun those confinement tmrriers that were identified in C.I. above. These systems regulatory guide i, expected to contribute to the safe operation of the plant in many ways, especially in the should give an audible and visual local alarm indication follow ing aspects: (1) an initial fire or explosion to operating personnel when the presenbed safe hmits a ccident ts unlikely to happen since an alarm wdl for combustible gas and vapor mixtures have been indicate when the flammable hmit is bemg approadied, adueved or exceeded.
(2) the need for admmistrative involvement should be mmamal since the system can provide continuous 4 The procedure for remedial action to be taken automatic survedlance, and (3) unexpected combustibie tn the event of an alarm signal should be established.
products will have a high probability of bemg detected.
5.
The absence of an evident igmtion source C. REGULATORY POSITION within those confinement barriers postulated to contain combustible gases, solvents, or vapors does not relieve 1.
All proceues and plant operations carried out the requirement for a monitoring and alarm system.
in or associated with the confinement 4 barriers of a plutomum processtng and fuel fabrication plant should 6.
The monitoring and alarm system itself should potential sources of combustible not introduce an ignition source and should not affect be evaluated as solvents, gases, or vapors.
the mnfinement integrity.
2.
Where sources of combustible solvents, gases, or 7.
The morii'oring and alarm system should be vapors can be identified or postulated under normal or designed for in-place calibration and testing.
O 3.72