ML20127G959
| ML20127G959 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 06/19/1985 |
| From: | Lundvall A BALTIMORE GAS & ELECTRIC CO. |
| To: | Butcher E Office of Nuclear Reactor Regulation |
| References | |
| RTR-REGGD-01.097, RTR-REGGD-1.097 NUDOCS 8506260148 | |
| Download: ML20127G959 (4) | |
Text
,
9 i
BALTIMORE GAS AND ELECTRIC.
j i
T CHARLES CENTER P.O. BOX 1476 BALTIMORE, MARYLAND 21203 ARTMum L LUNDVALL. JR.
vice Pats 1 DENT.
d SUPPLY Director of Nuclear Reactor Regulation Attention: Mr. E. 3. Butcher, 3r., Chief Operating Reactors Branch #3 Division of Licensing U.S. Nuclear Regulatory Commission Washington, D.C. 20555
Subject:
Calvert Cliffs Nuclear Power Plant Units Nos.1 & 2; Dockets Nos. 50-31;7 and 50-318 j
Confirmation of R.G.1.97 Implementation Schedule, Gentlemen:
1 On June 8,1985, you verbally requested confirmation of our planned schedule for completion of instrumenation upgrades to achieve conformance with the criteria of '
The results of our evaluation of accident monitoring instrumentation at Calvert Cliffs were submitted to you by letter dated December 1,o 1984. The enclosure to that letter included a schedule (Table 2), and a description)
(Attachment A) of all planned equipment modifications, with one exception. The plan' and schedule for the core exit thermocouple (CET) monitoring system was indicated as "under development."
Our schedule for implementation of the CET monitoring system is provided below. Clarification or confirmation of our schedules for other R.G.1.97 work items is also provided below. J CET Monitoring System y
AJdetailed design evaluatio'n 'of the CET monitoring system planned for installation 4t Calvert Cliffs will be submitted to you by July-1,1985, in response to your letter dated January 22,1985.
/
The scope. of modifications planned for this system include installation of safety-related control room displays and associated cabling and signal processing equipment outside containment, and replacement of all cabling inside containment. In addition, incore instrumentation (ICI) " strings" will be replaced on a schedule consistent with the ' depletion / failure of nuclear flux monitoring instrumentation associated with the ICI strings.
Our schedule calls for delivery of equipment and materials during 1986 in support of completion of system installation by the'end of the Fall 1986 Unit 1 (Cycle 9) refueling outage and the Spring 1987 Unit 2 (Cycle 8) ref_ueling outage.
System '
functional testing, calibration, and operator familiarization activities will proceed at 62gog 8 7
0 0
F I g.
i
Mr. E. 3. Butcher June 19,1985 each unit through one full refueling cycle.
Training, procedure revisions, and maintenance / calibration provisions will be finalized by the end of the Unit 1 Spring 1988 (Cycle 10) and Unit 2 Fall 1988 (Cycle 9) refueling outages, at which time the system will be formally declared operational.
Following installation during the Unit 1 Fall 1986 (Cycle 9) and Unit 2 Spring 1987 (Cycle 8) refueling outages, the system will satisfy all design requirements with two exceptions. First, when the system is installed, it will be served only by the safety-related control room backup display. The primary display will be implemented as part of the plant computer project, which is on a separate schedule.
Second, the cable-to-incore instrument connector on certain of the CET enannels will not satisfy environmental qualification requirements. This component is lucated on top of the ICI guide tube flange on the reactor vessel head and is integral to the existing ICI strings. The primary operational function of this incore instrumentation is to monitor core power distribution and peaking factors. Each instrument string consists of four rhodium self-powered neutron detectors (SPNDs) and one CET. The replacement schedule for the ICI strings is set by the failure or depletion of the SPNDs, or other j
situations which render a string unusable for nuclear monitoring. Replacements are l
planned and made such that the requisite number of SPND's will be available throughout the cycle, taking into account potential failures during the upcoming cycle. Typically, between 14 and 20 ICis are replaced each fuel cycle (there are a total of 45).
Replacements must be ordered approximately nine months prior to shutdown for refueling.
Concurrent with installation of the CET monitoring system, replacement ICI strings will incorporate an environmentally qualified connector assembly.
Prior to startup from the refueling outage following installation (Cycles 10 and 9 for Units 1 and 2, respectively) sufficient additional ICI strings will be replaced to provide for four completely qualified CET channels per core quadrant. Future replacement ICI strings will incorporate the qualified connector.
This will ultimately result in all 45 CET channels being qualified.
This implementation schedule is justified for the following reasons:
- 1. Initial installation is outage-related and is constrained by the scheduled delivery of equipment in 1986;
- 2. BG&E's experience with new instrumentation systems indicates that a functional checkout and familiarization period of approximately one refueling cycle is typically required to resolve technical problems and complete adminstrative work (procedures, manuals and training); and
- 3. This schedule is consistent with the results of a BG&E management prioritization of NRC-required modifications and BG&E plant betterment initiatives. This prioritization was conducted under the new Calvert Cliffs Integrated Management System, which is currently under development.
The phased replacement schedule for the ICIs is justified on the basis that:
- 1. The ICI replacement schedule is established by fuel management needs;
- 2. Discarding functioning ICI strings is wasteful of resources (each ICI string costs approximately $25,000 with an additional $5,000 required to ship and dispose of each string as nuclear waste);
i
Mr. E. 3. Butcher June 19,1985
- 3. Replacement of ICis is time consuming and thus is a dose intensive activity.
Unnecessarily increasing the number of ICis replaced during a refueling outage will result in an increase in man-rem expended, will create additional highly radioactive waste, and may increase overall planned outage duration; and
- 4. Finally, the CET monitoring (system will meet all other design requirements prior to the Unit 1 Spring 1988 Cycle 10) and Unit 2 Fall 1988 (Cycle 9) outages.
Thus, during the period in which certain CET channels will contain unqualified connectors at the ICI-to-cable interface, displays of all 45 CETs will be available on the safety-related control room displays.
Heated Junction Thermocouole (H3TC)
The H3TC system will be installed during the Unit 1 Fall 1986 (Cycle 9) and Unit 2 Fall 1985 (Cycle 7) refueling outages. As with the CET monitoring system, the H3TC system will be declared operable following one fuel cycle.
Thus, the final implementation dates correspond to the Spring 1988 (Cycle 10) and Spring 1987 (Cycle 8) refueling outages for Units 1 and 2, respectively. The safety-related backup control room displays will be available at the time of H3TC installation; however, the primary diplays are part of the plant computer replacement project, which is on a separate schedule.
Wide Range Ex-Core Neutron Detector We are currently studying instrumentation systems which may be capable of satisfying the operational criteria of this post-accident parameter. Whereas no design has yet been identified as suitable, we are evaluating a few options which may support implementation during the Fall 1986 and Spring 1987 refueling outages of Units 1 and 2, respectively.
Boronmeter Modification The schedule for completion of this upgrade is December 31,1985.
Boric Acid Charging Flow Indication Due to the system operating environment, we have had difficulty identifying an instrument capable of satisfying this function. We are investigating an instrument that employs a design which is more suitable to the operating environment than existing instrumentation.
If this investigation concludes favorably, we will install the new instrumentation by March 31,1986.
Mr. E. 3. Butch;r Juna 19,1985 Miscellaneous Upgrades for R.G.1.97 All other modifications identified in our letter of December 1,1984 will be completed during the Fall 1986 and Spring 1987 refueling outages for Units I and 2, respectively.
If you should have any questions, please do not hesitate to contact us.
Very truly yours, 3
C. H. Poindexter for A. E. Lundvall AEL/BSM/vf cc: D. A. Brune, Esq.
G. F. Trowbridge, Esq.
Mr. D. H. Jaffe, NRC Mr. T. Foley, NRC