ML19341B221
| ML19341B221 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 01/11/1981 |
| From: | Scott D COMMONWEALTH EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 81-24, NUDOCS 8101300470 | |
| Download: ML19341B221 (3) | |
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s NW Mr. James G. Keppler, Regional Director Directorate of Regulatory Operations - Region III U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137 Ref: (a) Nov 14, 1980 letter from J. Keppler to C. Reed We have reviewed the concerns noted in Reference (a) pertaining to the alle;;ed water J oss f rom Dresden. We believe the following response will resolve those questions.
Our report of October 30, 1980, noted two storm sewer sample locations which contained between 191 and 355 pCi/t.
The sewer located near the Unit 2/3 bunker "C" oil storage tank is the final sewer prior to storm water discharge to the canal leading to our cooling lake.
This location was resampled on October 30, November 19, and December 16, with results of 83 pC1/t, <LLD, and 60 pCi/t respectively.
Also, through-out our investigation during August, samples of sewer locations upstream of this final discharge location were less than 100 pCi/1, indicating that no contaminated water was being discharged from this sewer system.
The storm sewer located near Unit 1 "B" Condensate Storate Tank con-tained stagnant water for the sampling and analysis results that were reported. We do not believe these sample results are representa-tive of water that would flow through the storm sewer. Additional samples at a downstream location near the discharge of this storm sewer were collected during August and subsequently on October 24, November 19, and December 16, and indicated < LLD, 96 pCi/1, 72 pCi/t, and
< LLD respectively.
The recent routine sample results further indicate that we are not releasing contaminated water from the site via this potential pathway..
We agree with your observation that there must be a correlation between Condensate Storage Tank inventory depletion and ventilation system evaporative losses due to minor in-plant steam leaks.
- But, in addition to supplying maku-up water to the steam cycle, these tanks supply water for many unmetered uses in the plant.
Since all the sources of water into these tanks and use from them are not measured, we are unable to quantify any correlation between tank inventory and evapora-tion losses.
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The following is our latest data on evaporative losses from Turbine and Reactor Building Ventilation Systems:
Unit 2*
Unit 3*
Unit 2 Unit 3 Turbine Turbine Reactor Reactor Period Bldg. gpm Bldg. Epm Bldg. gpm Bldg. gpm 9/30-10/07 11.2 8.1 1.2 0.8 10/07-10/15 5.3 8.5 1.3 1.1 10/15-10/23 9.5 8.0 1.3 1.2 10/23-10/31 11.0 8.7 1.4 2.5 10/31-11/07 9.9 8.6 1.2 1.4 11/07-01/14 11.5 8.1 1.2 1.3 11/14-11/21 9.8 10.4 0.9 1.7 11/21-12/01 7.3 7.8 1.6 1.8 12/01-12/08 4.8
- 9. 0 2.4 2.8
- As reported by our consultant, these results may be 20%
high due to the use of design ventilation flow in the calculations.
During the period 12-1 to 12-18, Dresden Unit 2 was shutdown for three days which resulted in decreased evaporative losses. We have concluded that steam leaks are a significant contributor to evaporative losses, and the depletion of the Condensate Storage Tank inventory results from makeup to the steam cycle.
If any subsequent sampics change our conclusion, we will inform your office.
We do not believe that there is or has been a direct unmonitored release of water from the station.
This has been repeatedly confirmed by our effluent monitoring program. The apparent water loss was de-tected by use of a very basic water inventory system that was designed to assist in making liquid radwaste system processing decisions, but not to determine leakage from or to the system.
It did not take into account evaporative losses. For the period of 9-30 to 12-08, our basic water inventory, with metered inputs from clean systems factored in, indicates losses of about 10 gpm.
In August, this type of data became the basis for our concern about unmonitored water losses which was reported in the news media. Ilowever, the independent survey of evaporative losses for the same period indicate about 17 gpm.
Thus, from this data, we have unmetered inputs to our plant radwaste and condensate system of 7 gpm. These inputs occur when cican non-contaminated water enters our radwaste system via leakage from our
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heating boilers, laundry washing water, storm and ground water seepage and uses of cican water in the plant for cicaning and decontamination efforts. We feel that investigative efforts have subsequently proved that there has not been an unmonitored loss of water from Dresden Station.
Sincero y,
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D! J. Scott Station Superintendent Dresden Nuclear Power Station DJS/DA/lg cc:
C. Reed F. Palmcr D. Farrar D. Adam File /NRC