ML19220B165
| ML19220B165 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 02/16/1977 |
| From: | Vollmer R Office of Nuclear Reactor Regulation |
| To: | Vassallo D Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7904250489 | |
| Download: ML19220B165 (6) | |
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Oi 1 6 1577 Cockek. !'o. 50-320 ME!' ORA!iDU!i FOR: Doreqic B. Vassallo, Assistant Director for Liet Nater Reactors, CP!'
FROM:
Richard H. Vollmer, Assistant Director for Site Analysis, DSE SUN ECT:
THREE MILE ISLAND Ut!IT tl0. 2 SER SUPPLE!'c':TAL !!!cVT PLANT NAME: Three File Island Unit ?!o. 2 LICENSI?!G STAGE: CL 00CKET NtMER: 50-320 f tILESTOP!E HUPSER: N/A RESP 0!iSIBLE SRANCH: LW1 No. 2; H. Silver, LP" RE00ESTED C0f'PLETIGH DATE: N/A REVIEW STATUS: AAB Review Conclete Attached is the revised Accident Analysis Branch SER Suncleental incut for the Three Mile Island Nuclear Unit No. 2 facility. The LOCA ccses are based on the modified containment spray system which new uses 'laOH for iodine reroval.
The LCCA dosu were ccmouted using our standard assumntions, with values of meteorologic;l dispersion provided by H"B (see NU9EG-0107 ';ection 2.3. A).
As pointed out in Section 2.3.4, the HMS calculated at-osrh eic dispersion factors (X/0) were increased by 20% to include a narqin to ecccmocate uncertainties resulting from less than 80'i, data recnvery.
t...oed cn our discussions with HM8 staff, we believe that certain other conservatisms are included (the use of a ER distance in one sector that is less than that which actually exists, the lack of credit given to the increased ciscersion tnat could be expected for plu'.e trajectcries towards the cooling towers - which are in the direction of the shortest site bcundary distance).
However, since the effect of these factors has not been cuantified, we have used the Section 2.3.4 value of 1.1 x 10-4 seconds per cubic meter.
Based on this value, and cur other standard asst. stions, we conclude that a containnent leak rate of 0.14". per day is recuired to reduce doses to confom to the dose guidelines of 10 CFR 100.
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P,1 chard H. Vollmer, Assistant Director for Site Analysis Division of Site Safety and L.nvironmental Anaissis inclosure:
Three flile Island L' nit ho. 2 SER Supplemental In;;ut cc:
S. nanauer Distribution
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/A8 Reading F. Miraglia riRR Reading R. Vollmer DSE Reading J. Miller AAB Reading (Tiiree Mile Island)
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. We conclude *. hat, with a containment design leak rate of 0.14", ::er day, tr.e cal-culated two-hour thyroid dose at the nearest exclusion Ecundary is 300 rem anc that this is in conformance with the guideline values of 10 CFR Part 100, and is acceptable.
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TAELE 15.3 Doses calculated using Table 15.2 assum::tions:
Thyroid Whole Body
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TABLE 15.2 Pcwer 2772 MWt Fission Product Release (as per R. G.1.4)
- Containment Design Leak Rate 0.!4%/ day (0-24 hrs.)
0.07",/ day (24-720 brs.)
0
- Scrayed Containment 'lolume 1.764 x 10 ft 3
3 "Unscrayed Containment '/olume 3.950 x 1C ft
- Mixing Rate Eetween Sprayed and 2.0 turncvers of un-Unsprayed Regions s;: rayed volumes /hr +
18,0C0 cfm Icdine Removal Coefficients Elemental 10.0 hrs-Crganic 0
-I Particulate 0.4 hrs
. mental Iodine CF 100 X/Q '/alues 610 meters (0-2 hrs. )
1.1 x 10-3 3218 meters (0-8 hrs.)
1.1 x 10-3218 n ers (8-24 hrs.)
6.7x10f 3218 met rs (24-96 hrs.)
2.5x10[
3218 meters (96-720 hrs.)
6.0 x 10-
./ d t_3 3,,
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6.3 Ccntainment Air Purification and Cleanuo System In the SER we reportec that the proposed spray additive system was not expected to ::e able to acnieve its de:ign criteria, and : hat, consequently, we required redesign of this system. The appl',; ant has proposed in an amendment to redesign the system to use sodium hydroxide as the only spray additive, instead of a mixture of sodium hydroxide and thiosulfate. We have reviewed the revised spray additive system and conclude that the new system, although slightly less effective for iodine washout in that it does not remove the organic form of iodine, results in a sufficiently rapid absorpticn of the dcminant elemental form to provide a sufficient degree of thyroid dose mitigation required to meet 10 CFR P;rt 1C0 guidelines.
The revised design includes injection of sodium hydroxide into the ECCS flow as well as the containment spray. This provisien results in a rapid increase in the aikalinity of the concainment sump solution following a loss-of-coolant acci-dent, and, therefore, meets the post-accident spray and sump pH rcquirements #or NaOH spray systems, as specifieu in Standard Review Plan 6.5.2.
Cur evaluation of the icdine removal effectiveness of the system results in
-I calculated removal rate coefficients O.3) of 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> and 0.4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />s-I for the elemental and particulate forms of iodine, respectively, in an e:timated 6
3 effective volume of 1.764 x 10 ft, which c:merises 825 of the total free volume of the contair. ment. A long-term containment sump solution pH above of 8.5 assures ecuilibrium partitioning of elemental iodine such that a CF of 100 is maintained in the containment.
15.3.2 Loss-of-Coolant Accident We have calculated the radiological consecuences of a postulated LCCA using cur evaluation of tne redesigned scray additive system (see Section 6.31. Our assumo-tions in calculating the doses are shown in Table 15.2, wnile the doses are shown in Tacle 15.3.
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