ML20215N668
| ML20215N668 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 10/29/1986 |
| From: | Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Muller D Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-2.F.2, TASK-TM GL-84-23, NUDOCS 8611070143 | |
| Download: ML20215N668 (3) | |
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PHILADELPHIA ELECTRIC COMPANY 2301 MARKET STREET P.O. BOX 8699 j
PHILADELPHIA. PA.19101 (285) 841 5020 wuc6.
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October 29, 1986 Docket Nos. 50-277-50-278 Mr. Daniel R. Muller BWR Project Directorate #2 Division of BWR Licensing U.S. Nuclear Regulatory Commission Washington, D.C.
20555
SUBJECT:
Peach Bottom Atomic Power Station Reactor Vessel Water Level Instrumentation In BWRs (Generic Letter No. 84-23)
REFERENCE:
(1)
Correspondence dated December 5, 1984, S. L. Daltroff, PECo, to D. G. Eisenhut, NRC (2)
Correspondence dated April 18, 1985, S. L. Daltroff, PECo, to H. L. Thompson, Jr., NRC
Dear Mr. Muller:
This letter identifies the plans for upgrading the reactor water level instrumentation at the Peach Bottom Atomic I
Power Station Units 2 and 3 as requested by Generic Letter No.
84-23, dated October 26, 1984.
The letter meets a commitment in the reference (2) correspondence to identify our plans on this issue ninety days prior to the next refueling outage.
The modifications will be implemented during the next refueling outages for each unit (Unit 2:
Spring 1987; Unit 3:
Fall 1987), barring unforeseen delays in the procurement of the compensation instruments.
The modifications will reduce level indication errors during periods of high drywell temperature by rerouting portions of the level transmitter reference leg outside the drywell.
The following planned modifications were described in reference (1) correspondence and are repeated for your convenience.
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Mr. Daniol R. Muller October 29, 1986 Page 2 The wide-range.(- 165" to + 50") and fuel-zone (- 325" to 0) reactor vessel water level instrumentation will be modified as follows:
1.
The two existing temperature-compensated reference columns will be removed and replaced with condensing chambers which are not temperature compensated; 2.
The associated reference leg piping will be rerouted to limit the vertical drop inside the drywell to no more than three feet; 3.
The instruments will be recalibrated for the revised elevation of the condensing chamber and the new reference leg ambient conditions; 4.
The restricting orifices in the reference leg piping will be relocated as close to the containment penetration as practical in order to minimize the effects of flashing in the reference leg under certain postulated conditions.
(See Appendix B in SIL-8211,
" Review of BWR Reactor Vessel Water Level Measurement Systems", by S. Levy, Inc., prepared for BWR Owners' Group and referenced in Generic Letter 84-23).
5.
The reference leg for the fuel-zone level instruments will be moved from the existing GEMAC condensing chambers to the new condensing chambers.
The modification package improving the level instrumentation has been recently expanded to provide compensation for variation in reactor pressure.
The compensation for level measurement signals use for indication, recording and trip inputs to the ECCS systems will be provided through microprocessor instruments.
Four independent compensation instruments will be installed to provide two ranges of level indication and recording, and to provide four channels of inputs to the ECCS systems.
Each compensation instrument w'.ll receive inputs from two level transmitters and one reactor pressure transmitter.
The transmitters will provide wide-range and fuel-zone range monitoring.
Procurement of the components associated with the compensation feature is currently in progress.
Implementation of these modifications on each unit will complete the TMI Lessons Learned requirement, NUREG-0737, item II.F.2.
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Mr. Daniel R. Muller October 29, 1986 Page 3 Should you have.any questions regarding this matter, please do not hesitate to contact us.
Ve truly yours,
/
cc:
T.
P. Johnson, Resident Site Inspector