ML19256D294
| ML19256D294 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 03/31/1971 |
| From: | Ross D US ATOMIC ENERGY COMMISSION (AEC) |
| To: | Deyoung R US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| NUDOCS 7910170803 | |
| Download: ML19256D294 (5) | |
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/G March 31, 1971 R. C. De oung, Assistant Director for Pressurized Water Reactors, DRL v
THRU:
C. C. Long, Chief, PWR Project Branch No. 2, D?.L {, /{
MEETING WITH METROPOLITAN EDIS0N ON THREE MILE ISLA';D UNIT 1, DCCKET No.30-289
SUMMARY
We met with Met-Ed on March 23, 1971, to discuss onsite meteorolony, use of sodium thiosulfate, and Icng-term core cooling, in connection with the OL application for Unit 1.
As a result of the meteorology discussion, we are still unconvinced that Pasquill "F" and im/sec represents a 5% probability condition; we are continuing our study. We told Met-Ed that our calculation model for dose reduction for a sodium thiosulf ate plant was unchanged from that given them in a November 1970 meeting.
/. 2-hour dose proble.m still exists for this plant (D 2 328 Rem). We discussed long-ter.
cooling for a cold-leg break, with the potential for buildup of solids in the vessel.
B&W has two people working full time on a thermal-hydraulic code model, in an attempt to show adequate circulation of the vessel fluids.
Details of the meeting are in the enclosure.
A list of attendees is also enclosed.
M D. F. Ross PWR Project Branch No. 2 Division of Reactor Licensing Fnclosures:
l.
List of Attendees Compliance (2) 2.
Meeting Minutes DRL Branch Chiefs DRS Branch Chiefs Distribution:
D. F. Ross (3)
Docket file F. W. Karas DRL Reading R. W. Klecker PWR-2 Reading E. Markee P. A.
Morris W. Nischan F. Schroeder iA50 2 g T. R. Wilson R. S. Boyd R. C. DeYoung D. Skovholt E. G.
Case, DRS R. R. Maccary 7910170 03
E3:~.:. ::
1 L,IST OF ATTENDEES Met-Ed J. Bachofer, Jr.
GPU D. H. Reppert S. Bartnoff B&W D. Nitti J. F. Mallay M. M. Agen W. R. Smith W. S. Delicate J. M. Cutchin F. R. Ihommasson P-LA Keith Woodard NOAA I. VanderHoven AEC/DRL Earl Markee W. Nischan D. F. Ross C. G. Long
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__;tu;3J:.c 2 Pi.ETING WITH MET-ED ON ?! ARCH 23, 1971 RE THREE
} ELE ISLAND NUCLEAR UNIT 1 (50-289) 1.
Me teoroloev Keith Woodard of PLA discussed the new TMI-l meteorological station.
Trouble with the AT meter has been frequent; thermistor wires keep breaking.
As a result, little data are available.
About 2 menths of bivane data at 100' elevation have been accumulated.
He discussed six points that had been given to him as an agenda:
a.
Jalms Classification They now categorize calms as u = 0.5 m/see with the indicated Pasquill condition from the bivane.
b.
Calm Percentages Calm percentages are now being reevaluated.
They occur sligh)~ less than 4% of the time.
c.
Unsteadv Conditions Unsteady wind conditions are also being reevaluated.
If the horizontal range was > 125*, it was arbitrarily limited to 125' in the data reduction for daytime con-ditions (Pasquill "B"). At night, if a < 3 =ph and range
> 75*, the range was set at 30*.
Unsteady wind cor.ditiens are now being tagged in the data reuccion for retrieval purposes. They occurred 2.3% of the time, in 2 months of data. Most unsteady conditions occurred around d:wn.
di Woodted commented on the distribution of Pasquill con-di tions. He said errors in reducing range might have overproduced "A" conditions.
e.
Woodard discussed transition from 100' data to 30' data.
He said that some trees,75-100' tall, exist.cn the island and that the =cteorology tewer needed to be above that.
The tower is 300-40C' from the nearest trees.
He has estimated that going from 100' to 20' reduces wind speed by about a factor of two.
VanderHoven said that he though t the factor of two seemed reasonable.
Increased turbulence might mitigate the effect of reduced wind spped on X/Q, Woodard said.
1450 250'
m 2
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f.
Woodard discussed the procedure used in preparing Table 2-16; he said the WINDOW program was used.
VanderHoven asked about the 65% recovery f actor on meteorological data. He was concerned about the loss of blocks of data. Some dif ficulty in getting replacement parts for the tower has been experienced according to Woodard.
VanderHoven still wonders why 50-60% of categories are D or E:
he thinks it is too high.
For example, should 5% "F" frequency be adjacent to 30% "E"?
Woodard discussed the new data.
There has been difficulty with the temperature instrument, and no data are yet available. He has tried to set Pasquill categories with the bivane output, but he has only 2 months of data.
The average windspeed was 6.1 mph vs a 2-year average greater than 7 mph.
On the 5% proba-bility level the X/Q is close to "F", 1 m/sec.
For large horizontal ranges he saw significant vertical range.
About 3 more months will be required to obtain and reduce 2 months of AT data.
We caucused and decided that:
1.
N6 additional information was now needed from Met-Ed.
- 2. We foresee Safety Guide No. 4 as a lower limit on X/Q; Pasquill "F" and 1 m/see might be nonconservative.
3.
We are going to research the effect of using 100' tower data to get 30' values.
We communicated these points to Met-Ed.
2.
Sodium Thiosulfate Our previous discussion with Met-Ed in November 1970 on sodium thiosulfate disclostd to Met-Ed our dose calculational procedures.
We told Met-Ed that there would be no changes in that model on a time scale relevant to Unit 1.
As a result the 2-hour dose is 328 Rem thyroid.
(The current leak rate for the containment is 0.2%/ day.) We told Met-Ed that the meteorology is not going to improve, and may get worse.
Consequently, we said they must take action to modify their design so as to comply with Part 100.
1450 25i
~,
J 3.
Long-Term Core Coolin We presented our calculations on buildup of solids wherein heat transfer from tne core folleving a cold le; break is by evaporati:n only (thus causing a concentration of solids in the vessel).
Jim Mallay of B&W said that our input ass umotions we re reas on ab l/
correct.
Don Nitti of 3&'./ said that the buildup of solids should not proceed beyond the point when the original mass of solids,ecule be in solution in the vessel. We agreed that we had not taken that into consideration. We predicted that boric acid would reach saturation between 12-24 hours.
B&W stated that they were working on a computer analysis of the thermal-hydraulic aspects of the problem.
They hope to show that there is some circulation and purging of solids.
No time-table of resolution is available.
This concluded the meeting.
1450 2.52