ML20210K798
| ML20210K798 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 04/24/1986 |
| From: | Hukill H GENERAL PUBLIC UTILITIES CORP. |
| To: | Stolz J Office of Nuclear Reactor Regulation |
| References | |
| 5211-86-2065, NUDOCS 8604290062 | |
| Download: ML20210K798 (2) | |
Text
GPU Nuclear Corporation Nuclear
=;,orps=8o Middletown, Pennsylvania 17057 0191 717 944 7621 TELEX 84 2388 Writer's Direct Dial Number:
April 24,1986 5211-86-2065 Office of Nuclear Reactor Regulation ATTN: Mr. J. F. Stolz, Director PWR Projects Directorate No. 6 Division of Licensing U.S. Nuclear Regulatory Commission Washington, DC 20555
Dear Mr. Stolz:
Three Mile Island Nuclear Station Unit 1 (TMI-1)
Operating License No. DPR-50 Docket No. 50-289 Decay Heat Removal (TSCR 142)
This is to provide the confirmation requested in response to your letter of January 9,1986 regarding Decay Heat Removal, Technical S r -ification Change Request (TSCR) No. 142. Your concern was based on Westingnouse plants where analyses show that DNB criteria specified in GDC-10 may be violated for a rod withdrawal event during their Mode 3 operation (Hot Shutdown) with less than two reactor coolant loops in operation. Specifically, your question relates to TMI-l plant conditions between 200-250*F with less than two reactor coolant loops in cperation and whether TSCR 142 might allow cperation which poses a problem similar to that of the Westinghouse plant.
TSCR 142 does not allow TMI-l to operate in any condition less restrictive than the present Technical Specifications.
Rather, TSCR 142 places additional restrictions on which systems rmst be operational when reactor coolant temperature is between 200 and 750*F.
When TMI-l is in the temperature range between 200 and 250*F, the reactor coolant system is at least 1% A k/k subcritical and the pressure must be below 1720 psig in order to meet the pressure / temperature limits in TS 3.1.2.1.
The reactor protection system will be in the shutdown bypass mode with the nuclear over-power trip setpoint reduced to a value < 5% of rated power and the over-pressure trip setpoint automatically reWuced to 1720 psig (TS 2.3.1).
TMI-l Technical Specification (TS) 3.1.3.1 requires that reactor coolant temperature be above 525'r before going critical. The only exception to this requirement is during low power physics testing.
During this condition aJditional safety margin is maintained per TS 3.1.9.
The additional safety margin is obtained by setting the nuclear over-power trip setpoint 5 5% of rated power and maintaining a shutdown margin > 1% A k/k.
8604290062 860424 POR ADOCK 05000289 P
PDR uru nuuom vv.ev.m.v...., a subsidiary of the General Put;;lc Utilities Corporation gdol t\\ 0
<g 5211-86-2065 2-April 24, 1986
. Therefore, in light of the above discussion, the changes proposed in TSCR 142 i-do not allow operation in a manner which violates 10 CFR 50.36, or GDC-10, or allow operation not bounded by the TMI-l FSAR accident analysis.
In addition, the changes proposed in TSCR 142 will increase the margin of safety for the operation of TMI-l in the temperature range between 200 and 250*F.
If you have any further concerns regarding DNB under low temperature conditfor.s at 1
TMI we believe these should be addressed independently of TSCR 142.
Sincerely,
/ )
. D. I ill Director, TMI-l HDH/MRK/ew cc:
J. Thoma R. Conte 0563A T
---,c c.-
n.-,---,,-,---w,-ec,,
---,,----,n-w-e a<
-,