ML20246G304
| ML20246G304 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 07/05/1989 |
| From: | Hukill H GENERAL PUBLIC UTILITIES CORP. |
| To: | Russell W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| C311-89-2064, NUDOCS 8907140227 | |
| Download: ML20246G304 (3) | |
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GPU Nuclear Corporation Nuclear
- ,omareo Middletown, Pennsylvania 17057 0191 717 944 7021 TELEX 84 2386 Writer's Direct Dial Number:
l July 5, 3S89 C311-89-2064 Mr. William T. Russell Region I,, Regional Administrator U.S. Nuclear Regul& tory Commission 475 Allendale Road King of Prussia, PA 19406
Dear Mr. Russell:
Three Mile Island Nuclear Station, Unit 1 (TMI-1)
Operating License No. DPR-50 Docket No. 50-289 Condenser Offgas Continuous Iodine Sampling System Status Letter On January 27, 1989, we provided a response to NRC Inspection Report 88-30 which addressed a concern about the ability of the Condenser Offgas Continuous Iodine Sampling System to provide a representative sample for iodines being released to the environment. We provided the results of a preliminary review of the operation of the system and stated that we expected to be able to determine the appropriate corrections for past effluent data by April 30. We have recently gathered sufficient data to determine the corrections required and are providing this letter to document the actions we have taken.
We identified the following items that potentially impact our ability to obtain a representative sample:
(1) moisture in the sample cartridge (2) type of iodine cartridge (charcoal vs. silver zeolite)
(3) sample flow rate (4) inleakage (5) internal leakage The actions taken to investigate these items were as follows:
(1) moisture in the sample cartridge To eliminate moisture in the cartridge, additional fiberglass insulation was installed. The amount of heat trace was also increased. This includes the flow meter so that it would not act as a heat sink. The heat trace is constantly energized to avoid large temperature fluctuations and maintain a sample flow stream temperature in the range of 130*F.
8907140227 890705 PDR ADOCK 05000289 Q
FDC 4
GPU Nuclear Corporation is a subsidiary of the General Public Utilities Corporation 1
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C3'11-89-2064 July 5, 1989 l
(2) type of iodine cartridge l
We have determined through field testing that charcoal cartridges are superior to silver zeolite cartridges for this system. This may be due to the organic loading in the sample stream. We will review other sampling systems where silver zeolite cartridges are used to assure the suitability of the use of silver zeolite. We have demonstrated through the use of activated charcoal cartridges in series, a filter efficiency of greater than 95%.
(3) sample flow rate The sample flow rate being used was determined to be too high. The flow was calculated, and a new flow meter was installed for measurement of the lower flow.
(4) inleakage To eliminate the possibility of sample cartridge inlcakage, we improved the internal seals of the sample holder by adding an internal flat gasket and applied pipe grease on the threaded portions and 0-rings of the sample holder.
(5) internal leakage To prevent internal leakage (leakage internally around the cartridge), the improvements described in item (4) were made.
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To determine the corrections required for past data, we calculated an iodine partitioning factor. This factor is based on RCS iodine concentration, primary to secondary leak rates and reliable samples of condenser offgas iodine concentrations. Using known values for leak rate and RCS iodine concentrations, a calculation of the amount of iodine reaching the secondary plant compared to the amount of iodine actually rs eased yields a conservative partitioning factor of 60.
1 Using historical plant datc and the iodine partitioning factor, we have determined the revised contribution of condenser offgas iodine to the total maximum individual dose for iodines and particulate for the fourth quarter of 1988, which we consider to be a typical quarter. The value used for the fourth quarter of 1988 input to the Semi-Annual Effluent Report, which was submitted February 28, 1989, w&s 3.7E-3 mrem thyroid. The revised value is 1.7E-2 mrem 1
thyroid. The revised value represents 0.23% of the Technical Specification quarterly limit.
We will complete the revision of past effluent data and submit revised reports by July 31, 1989.
Sincerely, i
D.
UT 1 '
Vice President & Director, TMI-1 HDH/SM0/spb:2064 um m_ m mm m
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