Lecture 13

# Lecture 13 - 1 Radon NSS and Non-conservative MFB ย...

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Unformatted text preview: 1 Radon: NSS and Non-conservative MFB ยก Lecture#13 ยก review reaction kinetics ยก radioactive decay (1 st order kinetics) ยก non steady state (NSS), non conservative (CMFR) ยก ICP #11 ยก Reading V: Ch 5 (pg. 98-100; 110-111); Handout DFE2; Radon Guide Posted on Website What you should learn today ยก Why is radon a problem in homes? ยก Can we fix the radon problem? ยก How do we set up and solve non steady-state, non-conservative CMFR problems? Reaction kinetics ยก R = rate of reaction (mass/volume-time โก g/L-d) ยก m โ rxn = ยฑ VR โ units of mass flow ( โก g/d); โ for decay; + generation ยก R = kC n Where k is the rate constant, n is the order of reaction, and C is the contaminant concentration ยก reaction order, n n=0; zero order n=1; first order n=2; second order ยก unit of k โ depends on order such that kC n will give units of g/L-d n=0; k โก g/L-d n=1; k โก 1/d n=2; k โก L/g-d Batch with 1 st order reaction kinetics ยก for no flow reaction: dm/dt = m โ rxn = ยฑ VR ยก R = kC n ยก for 1 st order reaction, n=1, R = kC (k โก 1/d) ยก dm/dt = VdC/dt = -VkC (for decay) ยก dC/dt = -kC โ dC/C = -kt (integrate) ยก C=C exp(-kt) dm/dt = VdC/dt = m โ in- m โ out + m โ rxn ICP#10 (review) ยก C = C CO exp(-k Co t) + C Cr exp(-k Cr t) ยก t ยฝ = 0.693/k Co = (0.693/5.263 yr)(1yr/365d) k Co =3.6x10-4 d-1 ยก t ยฝ =0.693/k Cr = (0.693/26.5d) k Cr =2.6x10-2 d-1 ยก C Co = 1x10-3 Ci/L; C Cr = 1 Ci/L C = 100 ฮผ Ci/L when t = 17.5 yr (dictated by decay rate of 60 Co ( 51 Cr reaches 100 ฮผ Ci after 1 yr) ICP#10 (cont.) Radioactive Decay 0.0002 0.0004 0.0006 0.0008 0.001 0.0012 5 10 15 20 Time, years C u r i e s Total Cobalt Chromium...
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## This note was uploaded on 04/17/2008 for the course CEE 260 taught by Professor Kimf.hayes during the Fall '06 term at University of Michigan.

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Lecture 13 - 1 Radon NSS and Non-conservative MFB ย...

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