ML20059N229
| ML20059N229 | |
| Person / Time | |
|---|---|
| Issue date: | 09/24/1990 |
| From: | Trottier E Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| RTR-REGGD-01.033, RTR-REGGD-1.033 NUDOCS 9010110049 | |
| Download: ML20059N229 (5) | |
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k UNITED STATES g
g NUCLEAR REGULATORY COMMISSION L
j WASHINGTON, D. C. 20555 September 24, 1990 MEETING
SUMMARY
DATE:
August 21, 1990 l
SUBJECY:
INTERNAL MEETING ON RADIOLOGICAL METHODOLOGY TO BE USED AS BASIS FOR BWROG LCS EXEMPTION FROM PART 100 REQUIREMENTS l
LOCATIONS:
One White Flint North Room 14-B-9 PURPOSE:
Discuss impact (if any) of SAIC (Jim Cline) review of literature i
on deposition and resuspension.
(In particular, GE references.)
===1.
Background===
l There has been considerable discussion between the NRC and BWROG regarding the appropriateness of the radiological assumptions found in Reg Guide 1.3..
It has been, and continues to be, GE's position that the accident scurce tern for i
organic iodine (rethyl iodide, CH3-1) is conservative beyond reasonableness.
This has lead to GE's reluctance to address any pnenomenon that has the potential for increasing the organic iodine source term above its 4% value' leaking past the MSIVs.
(5tX of iodine inventory escapes core, 50% of that (25% of core l
iodine inventory,' reaches MSIVs, and 4% of that 25% is organic (methyl iodide) i iodine). This 4% 1rgsnic iodine and the balance (96% of the 25% is elemental snd other forms of iodine) enter the main steam lines. The 4%. organic iodine I
slowly makes its way toward the main conde: er, decaying as it travels. The remaining 96% is subject to several transformation mechanisms as it travels down the lines. Chief among these transformation mechanisms is deposition and-resuspension. These phenomena are scientifically well established and documented
[
in current literature.
The interesting (and in this case significant) thing about the deposition and resuspension phenomena is that no matter what form of iodine gets deposited (elemental or other forms), the iodine specie that resuspends is always methyl l
iodide. Thus, while the original 4% methyl iodide travels down the main steam pipe, neither depositing nor resuspending, the remaining 96% undergoes deposition and resuspension, with the resuspension product being more methyl iodice, t
The result of these phenomen is that the original 4% organic iodine is subject to increase. The magnitude of increase is affecttd by many variables. Chief among these is surface to volume ratio, but others such as temperature (decreases deposition and increases resuspension), flow velocity, and pipe surface conditions affect deposition and resuspension. Any resuspension above a negligible amount i
increases the percent of methyl iod Me that enters the main condenser. Current i
calculations by NRC consultant (Dr. J1., Cline of SAIC, Inc.) yielu approximately 8 to 10% methyl iodide entering the main condenser when deposition and resuspension t
are accounted for. This represents an approximate factor of 2 increase over j.
N NRC FRE CENTER COPY g
g3 9010110049 900924' h3 PDR ORG NRRD h
~
Meeting Summary September 24, 1990 the original 4% methyl iodide entering the main steam li?!*..
(Thesecalculations are based on best available data, typical BWR main steam piping runs and plant postaccidentconditions.)
Because of the dose consequences at the exclusion area boundary (25 rem whole body and 300 rem thyroid--see 10 CFR Part 100.11).. and because of the.above-referenced conservatisms of Reg Guide 1.3, the BWROG is reluctant to subscribe to any increase to the 4% organic iodine content.
II. Highlights Kudrick asked the PRPB staff for assurance that all Reg Guide 1.3 radioisotopes (e.g., noble gasses) would appear and be accounted for in the NRC's methodology.
PRPB responded that they will address the noble gas concentration in their Safety Evaluation of the Topical Report and that individual plants will deal with noble gasses and other Reg Guide 1.3 species in their submittals. The question of how to accurately account for radiciodine given the current understanding' of its behavior is really the only major consideration at this time.
The NRC's consaltant in this matter, Dr. Jim Cline, presented a report of his review and analysis of the literature on this subject.
His literature search included GE references. Dr. Cline noted that the BWROG methodology did consider deposition, but did not consider resuspension.
(The GE computer code contains a fairly sophisticated term to secount for resusper.sion, but it is not used).
III. Action 1+ ems 1
a.
Validate Dr. Cline's code and calculations using GE code. Determine difference (s) and significance.
(Cline) b.
Determine current status of GE methodology and what their answer is to the resuspension phenomenon.
(Kudrick, Trottier; completed 28 Aug.)
c.
Determine what it will take to convince GE to consider and calculate resuspension.
(Lee, Kudrick, Cline; completed 31 Aug) d.
Ensure Dr. Cline has funding thru end_of fiscal year and that funding picks up for at least the balance c(calandar 1990.
(Essig)
[h E. H. Trottier, Project Manager l
Project Directorate 1-3 Division of Reactor Projects - I/II
Enclosure:
Attendance List 1
Meeting Summary 2-September 24, 1990 the original 4% methyl iodide entering the main steam lines.
(Thesec61culai, ions are based on best available data, typical BWR main steam piping runs and plant post accident conditions.)
Because of the dose consequences at the excludon area boundary (25 rem whole body and 300 rem thyroid--see 10 CFR Part 100,11), and because of.the above-referenced conservatisms of Reg Guide 1.3, the BWROG is reluctant to subscribe to any increase to the 4% organic iodine content, i
II. Highlights Kudrick asked the PRPB staff for assurance that all Reg Guide 1.3 radioisotopes (e.g., nob 11 3 asses) would appear and be accounted for in the NRC's methodology.
PRPB responded that they will address the eloble gas concentration in their Safety Evaluation of the Topical Report and-that individual plants will deal with noble gasses and other Reg Guide 1.3 species in their submittals. The question of how to accurately account for radioiodine given the current understanding
.t of its behavior is really the only major consideration at this time.
The NRC's consultant in this matter, Dr. Jim Cline, presented a report of his i
review and analysis of the literature on this subject. His literature search included GE references. Dr. Cline noted that the BWROG methodology did consider deposition, but did not consider resuspension.
(TheGEcomputercodecontains a fairly sophisticated term to account for resuspension, but it is not used).
III. Action Items a.
Validate Dr. Cline's code and calculations using GE code. Determine difference (s) and significance.
(Cline) b.
Determine current status of GE methodology and what their answer is to the resuspension phenomenon.
(Kudrick, Trottier; completed 28 Aug.)
c.
Determine what it will take to convince GE to consider.and calculate l.
resuspension.
(Lee, Kudrick, Citne; completed 31 Aug) 1 d.
Ensure Dr. Cline has funding thru end of fiscal year and that funding l
picks up for at least the balance of calandar 1990.- (Essig)
/s/
E. H. Trottier, Project Manger Project Directorate I-3 Division of Reactor Projects - I/II
Enclosure:
Attendance List
[InterpalsMeeting-BWROG]
t 3
D:PDI-2 tA WButler op13t/90
/ /90
ENCLOSURE a
I ATTENDANCE August 31, 1990 Name Oiganieau; i
T. Essig NRR J. Lee NRR J. Kudrick NRR i
J. Cline SAIC E. Trottier NRR e
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September 24, 1990 l*
DISTRIBUTION:
M '.
l NRC & Local PDRs l
TMurley FMiraglia 12/G/18 JPartlow 14/G/18 PDI-2 Reading SVarga,14/E/4 00rutchfield CRos:1 JRichardson AThadani l
OGC(GHoller)
BGrimes FCongel JRoe RWessman Glainas JZwolisnki BBoger-WTravers WButler ETrottier TEssig JLee JCline JKudrick M0'Brien i
EJordan, MNBB-3302 ACRS(10)
JCaldwell 1
i