ML19207B260
| ML19207B260 | |
| Person / Time | |
|---|---|
| Site: | Atlantic Nuclear Power Plant  |
| Issue date: | 07/06/1979 |
| From: | Haupt C Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7908230685 | |
| Download: ML19207B260 (3) | |
Text
{{#Wiki_filter: ~ ^ r):C -. L ms J .~ m w... Ps -< l 'J DISTRIBUTION i q i i.[ See attached distribution sheet + e f .s JUL 0 61979 t 1 .a Docket Ho.. ST:t 50-437 l Applicant: Offshore Power Systems (OPS) Facility: Floating Nuclear Power Plants (FMP) . s] SUCJECT: "EETIMG SU:"iARY OF JUNE 0,1979 0,i June a,1979 a recting was held in Pethesda, "aryland between representa-tives of OPS and staff n:emLers of the dRC. A list of attendees is attached. i The purnose of the c:eeting was to discuss the core-debris particle size j distribution, the nachanisns for particle dispersion outside of the FMP breakuater and related radiological dose calculations as related to a possible core-nelt accident at an FMP. In its assessnent of the core-nelt scenario at an FMP the staff nade several assunptions regarding the distribution of core-nelt debris external i to the breakuater: 1. all but the very finest particles cf core-riebris unuld Le essentially confined to the breakuater; and 2. only dissolveJ radioactivity would escape the breakwater. The
- i particles of core-debris would leach their radioactivity to the overlying uater.
The stated c' asis for concludino that particles would be largely confined uithin the breakvater was that the rechanical energy inside would te lou. Met transport of ? ~1 sedicents into the breakwater would be expected. The subject .i was only qualitatively treated in the FES, Part III and the ( Liquid Pathway Generic Study Report. The staff indicated it now considers that there is a snall l'ut finite probability for a significant portion of the core-debris to escape the breakwater as particles, both as core-debris (fuel, cladding, steel hull, concrete and i'g3) an.! naturally occuring sefinants and organic material contaninated within the breakuater. Mechanisms which could nobilize these particles could include the following: 7953W 79082 8 a. stean explosions; 0Q b. circulation due to waves; I c. circulation due to therral convet on fren hot core-debris; c i ;wk4,im4,.*-t%ww-i on-e f--th -send . i '., 0 current flowing @rcuchbreakutor opening; c,,,c.
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The radiological inpact of these insoluble particles upon ocean biota - w and to man through the food chain pathway night be different from that .j-analyzed for the soluble fraction of the core-debris. . j Discussions during the neeting centered about the following principal topics: i 1. Cor_c; debris particle formation and distribution j Ed The prine nochanism for forcation of micron sized particles would be a steam explosion. Although a stean explosion beneath the FNP -i following a core-melt accident is considered unlikely, such 1 an event cannot be precluded. Particle sizes following the stean . :j explosion could range between 10 - 250 microns. 2. Particle transoort :ithin the FMP breakwater Thermcl convection, turbulence, uave action, current flow, tidal -l action and flotation nay all be nechanisns that act singly or jointly in causing circulation of core-debris particles within the breakuater. Coth the staff cnd OPS estinaMd that thermal j convection alone could cause particles of up to 300 nicrons in dianeter to rise to the surfaca. } 3. Local area def_o,s_ition of particles _ 1 Particles large enough to settle would rove nainly during storns ~, as suspended load and perhaps as bedload during calner periods. The path and speed of their dispersion would likely be different ,i from that of dissolved radioactivity. Some particles would be H fine enough to remain suspended indefinitely and would probably
- i disperse in a way sinilar to dissolved radioactivity.
It is 4 -2 believed that nost of the particles could rer.;ain on the continental shelf and it is possible that a small fraction night enter into il estuaries alono the coastal zone. 5. Radiolo ncal conseouerces fron core-dcbris particles Core-debris particles may be nore persistent sources of radio-activity than the soluble fraction of core debris due to the likelihood of slower dispersion. Such levels of radiation in the vicinity of the FNP night lea to increased 'ortalities to dersrsal organisns and/or their w 7s. OPS estiriates that spproxinately the sana surface area of ocean could be contaninated indepenJent of whether the radioactivity was in the dissolved or insoluble phase, but the dose to biota could be higher in some cases for the insoluble case. Uith respect to dose to nan, i the biological accumulation factors (CAF) for soluble conponents -{ apoears to be greater than the CAFs for the insoluble forn for a i J 4
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/ ' ~~ ~... N, i - 4 4) a:3 - :q 1 najority of the isotopes. The calculations presented -11 in the FES, Part III and the Liquid Pathway Generic .d Study Report regarding dose to man fron the.oluble phase nay ] indeed bound the values for the insoluble. phase. The potentially ?d_.y higher activity of tne particles and their associated longer half-life should be considered in'any conparison of effects of insoluble and solubic fractions of radioactivity. OPS Leleives '1 that the actinides arid transuranics in the core vould not be ^'i najor factors in deternining the dose resultant from the particles. E-. 6. Mitiaation and interdiction of the core debris _ particles OPS estinates that approxinately the top 10 cra of the ocean l floce could be dredged to remove the principal radioactive contauinants. This would amount to about 4 nillion cubic yards of dredge spoils. The efforts associated with interdicticn and nitigation of the particles would be sinilar to that anticipated j for soluble radioactivity except for the aspect of dredginq a region or regions of contaninated ocean totton. i l As a result of this reeting it was concluded that the staff would ferr.: ally request OPS to respond to a series of questions concerning the nechanisms for dispersion and transport of core-debris particles as well as an assess:nent of the impacts to biota and nan froa such radioactive In preparing its resconse GPS uould conpare the results developed fcr the insoluble core-debris fraction with those previously deternined in the 3 FES, Part III and Liquid Pathway Generic Study Poport related to the soluble core-debris fraction. ~~ ,i Clifford A. !!aupt, Project 11anager Environuental Projects Eranch 1 Division of Site Safety l and Environmental /nalysis 1 i 'j $ f) 3 W t 4 1 f/ J2 (_.
- For concurrence see previous yellow.
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