ML19211C537
| ML19211C537 | |
| Person / Time | |
|---|---|
| Issue date: | 08/13/1979 |
| From: | Thadani A Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| REF-GTECI-A-09, REF-GTECI-SY, TASK-A-09, TASK-A-9, TASK-OR NUDOCS 8001110650 | |
| Download: ML19211C537 (2) | |
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wAsmwaroy. p.p.,aosss AUG 131979 Task Action Plan A-9 NOTE TO:
Files FROM:
Ashok Thadani This note records telephone conversation that Fuat Odar and I had with General Electric on 8/7/79. The subject matter was specific questions on radiological assessment and ATWS analysis code. The total list of questions was sent to GE on 8/6/79 and to the ATWS task group on 8/9/79.
Radiological Q.63 See Question list for question description Item 3g. GE: Alt. f4 not yet evaluated Alt. f3 - No degradation of seals expected and therefore none assumed.
NRC: Difficulties at THI-2 suggest that leakage can and does occur and that GE should review lessons learned report on this item and coment to us.
Item 31. j, k: Alt. d4 Item 31: Lc3kage pathways considered are containment and condenser and the leakage assumptions are conservative.
Item 3m: Part a: Release thru condenser considered Part b: Alt. f4 Q.64: GE did essentially what e s asked in 2/15/77 Mattson letter.
i.e. Tech Spec activity (TSA) x 250 = 1/2 TSA x 500
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1736 2/4 8001110 g
Note to Files AUG 131979 Q.65: GE analysis results in 3
1.2 x 10 Curies airborne in 1 minute 9.6 x 10 Curies airborne in 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> 3
Staff ass mptions yield 3.7 x 10 Curies airborne in 30 minutes GE feels cheir method is more appropriate.
Q.66: 0 x 8 assembly on all BWR 5/6 All operating BWRs are expected to have 8 x 8 assemblies by 111d'81-i.e. prior to ATWS fix is implemented.
Q.67: GE recommnds that the staff review Section 5.2.1, Q.30: GE was told that the staff had recomended use of 90% efficiency of SGTS filter and not 95%.
GE stated that in the worst case this assump-tion would result in a factor of five increase in radiological dose values.
However, GE believes the final radiological dose would still be far below 10 CFR 100 guideline value.
Computer Code We described our concerns with the use of REDY code for ATWS analyses, (These concerns are documented in nty note to M, Aycock dated 8/8/79),
GE stated the following concerns with using ODYN code for ATWS calculations, a) No film boiling heat transfer model - minor problem b) ATWS long term core flow less than 20% - ODYN hydraulic model may be inadequate and the code may be susceptible to numerical uncertainties.
This raises the concern of accuracy after about 30 seconds in the transient, c) The reactivity model in the ODYN code does not have provision for Boron injection, Staff asked GE to comp ^re ODYN/REDY calculations for all overpressure transients for all classes of plants for s 60 seconds and if the results are not significantly different, REDY could be used for long term calculations. The staff also gathered from GE comments that the short term limitations of REDY (v60 sec, calculation) were not major and could be corrected in a reasonably short time period, (c) A kO M'
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Ashok Thadani 1736 275