This preview shows pages 1–2. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: 1 Radon: NSS and Non-conservative MFB Lecture#13 review reaction kinetics radioactive decay (1 st order kinetics) non steady state (NSS), non conservative (CMFR) ICP #11 Reading V: Ch 5 (pg. 98-100; 110-111); Handout DFE2; Radon Guide Posted on Website What you should learn today Why is radon a problem in homes? Can we fix the radon problem? How do we set up and solve non steady-state, non-conservative CMFR problems? Reaction kinetics R = rate of reaction (mass/volume-time g/L-d) m rxn = VR units of mass flow ( g/d); for decay; + generation R = kC n Where k is the rate constant, n is the order of reaction, and C is the contaminant concentration reaction order, n n=0; zero order n=1; first order n=2; second order unit of k depends on order such that kC n will give units of g/L-d n=0; k g/L-d n=1; k 1/d n=2; k L/g-d Batch with 1 st order reaction kinetics for no flow reaction: dm/dt = m rxn = VR R = kC n for 1 st order reaction, n=1, R = kC (k 1/d) dm/dt = VdC/dt = -VkC (for decay) dC/dt = -kC dC/C = -kt (integrate) C=C exp(-kt) dm/dt = VdC/dt = m in- m out + m rxn ICP#10 (review) C = C CO exp(-k Co t) + C Cr exp(-k Cr t) t = 0.693/k Co = (0.693/5.263 yr)(1yr/365d) k Co =3.6x10-4 d-1 t =0.693/k Cr = (0.693/26.5d) k Cr =2.6x10-2 d-1 C Co = 1x10-3 Ci/L; C Cr = 1 Ci/L C = 100 Ci/L when t = 17.5 yr (dictated by decay rate of 60 Co ( 51 Cr reaches 100 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...
View Full Document