ML20091K391
| ML20091K391 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 01/15/1992 |
| From: | Broughton T GENERAL PUBLIC UTILITIES CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| C311-92-2010, NUDOCS 9201240169 | |
| Download: ML20091K391 (2) | |
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3 GPU Nuclear Corporation j
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%ddletown, Pennsyivania 17057 0191 717 944 7621 TELEX 202386 Writer's Direct Dial Nurnber (717) 948-8005 January 15, 1992 C311-92-2010 U. S. Nuclear Regulatory Commission Attn:
Document Control Desk i
Washington, D.C.
20555
Dear Sir:
Subject:
Three Mile Island Nuclear Station, Unit 1 (TMI-1)
Operating License Nct OPR-50 Docket No. 50-289 Inspection Report (!R) 91-15 Supplemental Response - Radiological Effluent Moni+ ors On November 21, 1991, representatives of GPU Nuclear and the NRC participated in a conference call to continue discussion of two open items identified in Inspection Report (IR) 91-15.
GPU Nuclear had previously responded to these open items in a letter dated Ceptember 30,1991(C311-91-2096).
The conference call on Hove'nber 21, 1991 was beneficial in that it permitted the exchange of views on the issues and facilitated a better understanding by GPU Nuclear of the NRC concer..s.
It was agreed in the call that GPU Nuclear would submit a supplemental response by January 15, 1992.
The IR identified two unresolved items:
- 1) calibration of efflu9nt process radiation monitor:; and 2) validation of sensitivities of effluent monitors listed in the Offsite Dose Calculation Manual (ODCM). The particular radiation monitors identif;ed in the Inspection Report are RM-L6, RM-L12, RM-A4 Gas, RM-A5 Gas, RM-A6 Gas, RM-A7 Gas, RM A8 Gas, RM-A9 Gas, RM-A14 Gas, and RM-AIS Gas.
The first item was in regad to the pr wess presently used to calibrate these effluent radiation monitors.
TM1 wil
- .aceduralize and implement the following calibration methodology in a ce, dance with THI-l Technical Specifications SS3.2.1 and 4.2.1 to address the NRC concerns expressed in IR 91-15
1..
An electronic alignment check will be conducted to verify the ratemeter's linear response over its range.
This is being accomplished now in the current procedure, however the procedure will be revised to obtain a more formal presentation of the test and data.
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V Document Control Desk l
C311-92-2010 Page Two 2.
The channel calibration procedure will be revised to a include a linearity check at the Technical Specification calibration frequency (each refueling or every eighteen (18) months, as the case may be) to verify acceptable stability of the monitor's sensitivity.
This check will be performed with at least three (3) varying strength solid sources, in the past this has been accomplished every four years or when a detector was replaced, but not as part of the Technical Specification required calibration.
The second item concerned the methodology used to assure the radiation monitor sensitivities correlate to those used in the 1M1 ODCH. To address this concern, an evaluation was conducted of the current radiation monitor's response to actual plant effluent releases. This evaluation used the sensitivities for isotopes contained in the ODCM and vendor manuals to develop an expected reading on the radiation monitors.
The actual readings recorded during the releases were then compared to the expected readings based on sample results. The comparison was performed for monitors RM-L6, L7, A7, AB, A9 ai.d A15. Only the data from RM-AIS and RM-A7 was meaningful from the standpoint of the level of activity of the release versus background activity.
These monitors correlated well and demcostrated that the programmatic controls of the TMl-1 calibration process are acctptable.
Furthermore, the linearity data for all monitors demonstrated good historical correlation. Due to some data point scatter on the linearity for RM-L6 and RM-A9, GPU Nuclear intends to perform an isotopic calibration for these monitors.
We believe these additional commitments as discussed above satisfy the NRC's concerns expressed in Inspection Report 415 based on our conference call with the NRC on November 21, 1991.
As a result of our review of the radiation monitor test program, GPU Nuclear intends to submit a Technical Specification Change Request and reduce the current Radiation Monitoring System (RMS) quarterly calibration frequency for non-effluent monitors to a refueling interval requirement as currently specified in the Standard Technical Specifications (STS).
Sincerely,
&&nAA%
T.G.Broubton Vice President and Director, TMI-l DVH/mkk cc: TMI-l Senior Project Manager Region I Administrator TMl Senior Resident Inspector l
._