Problem Accurately monitor releases from

the RWST (for fuel failure conditions)

Why?

RA-RA-RA

Record All Releases As Reasonably Achievable

Problems/Issues

RWST (at MP) is vented to atmosphere

Source terms (makeup water) may contain significant amounts of activity (fuel failures)

Use of calculations has resulted in some issues (+5000 uCi of I-131 for 2R15, uncertainty)

RWST Vent Contaminated sources

(unprocessed pressurizer water, waste water, refuel cavity water, VCT see OE24665)

Source terms (Noble Gas, H-3, Iodines, Particulates)

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)

Iodines and Particulates – ???????

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 RWST2. Actual “effluent sampling” – HOW (e.g., OE24665; LLD)?

Temp Mod – Special Study

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)

RWST Tank Vent

Effluent Results – 2R17

Noble Gases Iodines Particulates

Noble Gases

Waste Tank (CWMT) transfer to RWST1st tank - 1.4 Ci 2nd tank - 0.7 Ci

Cavity Water transfer to RWST1st drain - 0.07 Ci2nd drain - 0 Ci

Outage Purge – 13 Ci Outage Ventilation – 3 Ci

I-131

Aux. Bldg Ventilation – 621 uCi (2e-2 mrem) Equipment hatch – 29 uCi (7e-4 mrem) RWST (prior to filt.) – 116 uCi (3e-3 mrem) RWST (after filtration) – 5.8 uCi (1e-4 mrem) Only saved 15% of total by filtration, but

this extra would have been ground level and now it was monitored

Note: Pressurizer replacement during 2R17

I-131 - Details

Waste Tank (CWMT) transfer to RWST1st - 74.6 uCi (2.3 uCi after filtration) 2nd - 9.8 uCi (0.77 uCi after filtration)

Cavity Water transfer to RWST1st - 29.9 uCi (2.18 uCi after filtration)2nd - 2.1 uCi (0.56 uCi after filtration)

Charcoal filtration varied in effectiveness – moisture issue

Results - Discovery

Iodine Reduction Factor (RF) “across tank”

1.6 for 1st CWMT - pH of 5.69 to 4.31 23 for 2nd CWMT - pH of 5.43 to 4.66 2770 for 1st Cavity drain – much

lesser pH change 9610 for 2nd Cavity drain - even

lesser pH change

Implications- I-131

Approximate 18% increase in 2R17 effluents (if unfiltered, but at ground level; of which 1/3 was due to cavity water)

Approximate 100% increase in 2R15 effluents (+5000 uCi, for RF = 100; this very likely unconservative based upon this “test”)

Unit 2 has HEPA on Auxiliary Building ventilation (no charcoal) – for plants with charcoal, the % will be significantly higher (factor of 4 increase for ventilation RF of 100, if equipment hatch releases same as ours)

LOCA assumptions – may be invalid – I-131 source term may be significantly higher than “expected” (leakage past isolation values and large pH difference, TSP in CTMT sump for LOCA)

Implications- I-131 (cont’d)

Effluent Results – 2R17

Particulates1. Aux. Building Ventilation – 0.3 uCi2. Equipment hatch – 3.6 uCi3. RWST (prior to filtration) – 7 uCi4. RWST (after filtration) – 0 uCi

Although RWST a significant component, iodine is much more limiting (for sites with no Aux Building HEPA, will be an insignificant component)

Results - Particulates

Reduction FactorsCo-58 – 2.4 e+4Co-60 – 4.3 e+4Nb-95 – 2.0 e+4Sb-125 – 1.3 e+6

Conclusion

RWST vent may be important for I-131 effluents:

Outages (could increase I-131 by factors of 1.2 to 4 or more & a ground level release)

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)

NRC Information Notices 86-60, 90-64 & 91-56

REMEMBER Think football/cheerleading –

summer football camp is almost here

RA – RA – RA