Outdoor Tanks – Potential Release Issues

1. Outdoor Tanks – Potential Release Issues • Vent – for some sites vented to atmosphere • Overflow line – to a pit or sump (difference?) – where does it go? • Tank leaks – are they contained, how well?

2. Vent • If to atmosphere, is it accounted? How (empirical, measured)? • Accurately monitor releases from the RWST (outages, fuel failure) • Why? Routine airborne releases typically low, may be a significant contributor to total iodine and/or particulate releases

3. Problems/Issues • Source terms (makeup water) may contain significant amounts of activity (fuel failures, crud burst) • Makeup water – RCS, “cleaned RCS,” refuel cavity, VCT see OE24665 • Source terms - Noble Gas, H-3, Iodines, Particulates • Use of calculations has resulted in some issues (+5000 uCi of I-131 for 2R15, doubled MP2 releases, “model” uncertainty, important parameters?)

4. Release Quantification • Noble gas – easy, just assume it is all released (or you could be less conservative and do an activity balance, i.e.. what’s released = what goes in – what stays in the RWST) • H-3 – release = water lost due to evaporation (we assumed negligible based upon review of another site’s method – also think about comparison to SFP; where does it go may be important - GPI) • Iodines and Particulates – ???????

5. Quantification – I & Part. • Calculations based upon source term & assumed RF’s (EPRI project NP-1271- Nuclear Power Plant Related Iodine Partition Coefficients) – Rad Engineering gave us #’s ranging from 100 – 3000 • Measurements1. Activity Balance – problems with tank recirculation, potential plateout in RWST, small % released, significant error in calc. (subtraction of large # from large #)2. Actual “effluent sampling” – HOW (e.g., OE24665; LLD)? When to sample?

6. Temp Mod – Special Study – 2R17 & 2R18 “Capture” and analyze the RWST “venting” • Vent pipe mod • Hoses • Moisture separator • Charcoal with pre-HEPA • HEPA • Air sample pumps/filters & sample nozzles (both pre and post filtration)

7. RWST Tank Vent

9. Effluent Results • 2R17 discussed at last year’s workshop • 2R18 results to be briefly discussed • What did we learn?

10. Noble Gases Released – 2R18 • Waste Tank (CWMT) transfer to RWST- (< 2R17)1st tank (cancelled) – 0.12 Ci 2nd & 3rd tank - 0.004 Ci each • Cavity Water transfer to RWST – (< 2R17) 1st drain - 0.003 Ci 2nd drain - 0.02 Ci • Outage Purge – 2.1 Ci (< 2R17) • Outage Ventilation – 7.6 Ci (> 2R17)

11. I-131 Released • Aux. Bldg Ventilation – 1056 uCi (> 2R17) • Equipment hatch – 2.4 uCi (< 2R17) • RWST (prior to filtration) – 3 uCi (<2R17) • RWST (after filtration) – 0 uCi (<2R17) • Did not discharge 1 CWMT (reason: chloride issue; 219 uCi) and the 2 others I-131 LLD, but detectable I-132; 2nd cavity transfer: I-131 LLD • Ground level vs mixed release height and now it was monitored Note: Alloy 600 replacement during 2R18

12. I-131/I-132 - Released • Waste Tanks and Cavity transferred within 1 day (not like 2R17); not able to differentiate the Iodine releases from them • I-131 & I-132 exhibited different DF’s (present in different ratios in tanks and cavity, able to show differences in DF’s with source terms (tanks vs. cavity) • Tanks had significantly lower DF (similar to 2R17)

13. DFs - I-131 • Transfer of waste tanks (2 – 100 DF) and initial cavity drain-down (2000 – 10000 DF) can contribute to significant iodine releases

14. Effluent Results – 2R17 • Particulates1. Aux. Building Ventilation – 5 uCi2. Equipment hatch – 14 uCi3. RWST (prior to filtration) – 18 uCi4. RWST (after filtration) – 0 uCi (similar to 2R17) • Although RWST has a significant particulate component, iodine likely more limiting (for doses, dependent on fuel failure) (for sites with no Aux Building HEPA, will be a less significant component)

15. Results - Particulates • Reduction Factors 2R17 2R18Co-58 – 2.4 e+4 1e+6Co-60 – 4.3 e+4 2e+5Nb-95 – 2.0 e+4 2.5e+5Ag-110m 2e+4Sn-124&125 5e+4 Sb-125 – 1.3 e+6 1e+6

16. RWST Vent Releases - Conclusion RWST vent may be important for I-131 & particulate effluents: • Outages (could increase I-131 by factors of 1 to 4 or more & a ground level release – depends on several variables) • Other events (see OE24665) • LOCA analyses (pH from 7 to 4.6 may cause a significant fraction of the I-131 going over to the RWST to be released - leakage past isolation values and large pH difference, TSP in CTMT sump for LOCA) - existing LOCA assumptions – may be invalid – I-131 source term may be significantly higher than “expected”) • NRC Information Notices 86-60, 90-64 & 91-56 • Particulate releases – significant compared to other source terms - could explain why we had trace particulate contamination in the MP3 yard • Considering MP3 temp mod for 3R12 (next outage is this Fall)

17. Foundation Drain Sump 3 (ESF)

18. RWST Overflow Line • Found H-3 in MP3 foundation drain (great GPI sampling point(s); in a way, better than wells!) • Performed inspection of sump 3 – sampled 2 of the 3 inputs (third was “dry”) • Traced to RWST pit (diluted with rain, H-3: 4e-3 uCi/ml = 4e+6 pCi/liter; Cs-134, Cs-137, Ni-63 – supports RWST vent “carryover” of particulates) • RWST oveflow pipe – H-3, Co-60 and Cs-127 • Source – RWST overflow line (RWST H-3: 2e-1 uCi/ml) • Not first time – H-3, Cr-51, Co-58,60, Nb-95 and Cs-137 in 2002

22. Sump 3 Actions • Short term corrective actionsincreased sampling, find source & minimize impact, determine extent of plume • Long term corrective actionseliminate source, remediation? • OE26024, OE26571 • What about MP2?

25. MP3 Waste Test Tanks • Negative suction tank vents – adequate? • Tank leaks (tank, piping, instrumentation) • Berm

26. Conclusion • Outdoor tanks are a “challenge” • RWST Vents – airborne • RWST Overflow Lines – GPI • Tank leaks – GPI