B12197, Forwards Reviews of Isap Topic 2.01, Secondary Side Chemistry Monitoring, Isap Topic 2.04, Modernize Reactor Protection & Control Sys & Isap Topic 2.05, Process Computer Replacement

Forwards Reviews of Isap Topic 2.01, Secondary Side Chemistry Monitoring, Isap Topic 2.04, Modernize Reactor Protection & Control Sys & Isap Topic 2.05, Process Computer Replacement

ML20214V806
Person / Time
Site:	Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	09/18/1986
From:	Opeka J, Sears C CONNECTICUT YANKEE ATOMIC POWER CO.
To:	Charemagne Grimes Office of Nuclear Reactor Regulation
References
B12197, NUDOCS 8610020415
Download: ML20214V806 (7)

Text

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CONNECTICUT YANKEE ATOMIC POWER COMPANY B E R L I N. CONNECTICUT P o BOX 270 HARTFORD CONNECTICUT 06141-0270 TELEPHONE September 18,1986 Docket No. 50-213 B12197 Office of Nuclear Reactor Regulation Attn: Mr. Christopher I. Grimes, Director Integrated Safety Assessment Project Directorate Division of PWR Licensing - B U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Gentlemen:

Haddam Neck Plant Integrated Safety Assessment Program In a letter dated July 31, 1985,(1) Connecticut Yankee Atomic Power Company (CYAPCO) was requested to provide the Staff with reviews of the planned CYAPCO plant improvement projects.

In response to this request, and in accordance with our understanding of the ISAP process, we are providing the Staff with reviews of the following projects:

1) ISAP Topic No. 2.01 " Secondary Side Chemistry Monitoring"

2) ISAP Topic No. 2.04 " Modernize Reactor Protection & Control Systems"

3) ISAP Topic No. 2.05 " Process Computer Replacement" As further reviews are completed, we will promptly forward them to the Staff for review.

If you have any questions on this material, please feel free to contact my staff.

Very truly yours, CONNECTICUT YANKEE ATOMIC POWER COMPANY

.hi F.A

3. F. Opeka '

Senior Vice President 8610020415 860918 13 DR ADOCK 0500 MQ By: C. F. Sears Vice President 00

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(1) H. L. Thompson letter to 3. F. Opeka, " Integrated Safety Assessment Program," July 31,1985.

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Docket No. 50-213 B12197 Haddam Neck ISAP Topic No. 2.01 Secondary Side Chemistry Monitoring September 1986

Haddam Neck ISAP Topic No. 2.01 Secondary Side Chemistry Monitoring

Background

The assessment of safety-related issues for internally-initiated events for nuclear power plants includes consideration of steam generator tube ruptures (SGTR). A SGTR event results in a loss of primary coolant inventory flowing out of the faulted steam generator (SG) and containment bypass. Without event mitigation, the potential for a direct. radiation release path to the environment exists. To help minimize the potential of such an occurrence, secondary side water chemistry is monitored and controlled to help prevent corrosion and tube degradation. Additional SG blowdown line instrumentation exists to assess the radiation level of the water, and is utilized in conjunction with the subject instruments.

CYAPCO's commitment to corrosion control is demonstrated through the usage of a corporate procedure for secondary water chemistry control whose implementation minimizes or eliminates corrosion phenomena that threaten the long-term lifetime of affected plant equipment.

Project Description Recommendations and guidelines have been established for chemistry programs designed to reduce the potential for corrosion and in turn, the probability of SGTR events. The proposed project is a three phase program to provide improved secondary side water chemistry monitoring in accordance with such guidelines. Phase I of the program involves the installation of new SG chemistry monitoring panels (1 panel per SG). This work has been completed. The panels provide continuous information on the sodium and chloride concentrations, and also the pH and conductivity of the SG blowdown water. The panels are located in the Primary Auxiliary Building and utilize the existing SG blowdown lines.

Phase 11 activity regards the routing of the four SG panel multiple signal outputs to the Chemistry Laboratory. Phase Ill will involve replacement of the Feed and Condensate rack instrumentation in a newly procured panel rack assembly. The Feed and Condensate panel assembly will be positioned where the existing rack is now and is virtually identical to the SG panels. The Chemistry Laboratory will contain a recorder and annunciator rack assembly for the new SG instrumentation panel signals as well as for instrumentation signals associated with the Feed and Condensate panels. The Phase ill effort will also involve dismantling the existing feed and condensate chemistry monitoring rack assembly and related instrumentation af ter satisfactory performance of the new panels is demonstrated. Minor piping changes may be required for the sample or drain lines for both the SG and Feed and Condensate panels. Phase 11 and Phase 111 activities will result in a more convenient methed of monitoring secondary water chemistry.

CYAPCO Evaluation Though this modification may reduce the probability of a SGTR scenario, it is expected that this project will not significantly decrease risk to the health and safety of the public. However, Phase 11 and Phase 111 will be evaluated further in the integrated assessment.

Docket No. 50-213 B12197 Haddam Neck ISAP Topic No.- 2.04 Modernize Reactor Protection & Control Systems September 1986

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Haddam Neck ISAP Topic No. 2.04 Modernize Reactor Protection and Control Systems

Background

A number of components in _ the reactor protection and control systems are approaching the end of their useful life. Although still highly reliable, the failure probability of these components is increasing. Thus, for many of these components the question of repair or replacement is surfacing. This question is compounded by the fact that some of the instrumentation from the reactor protection and control systems are of outdated design and spare parts are more difficult to obtain. Failure of components in these systems could reduce the reliability of the reactor protection system (RPS), or lead to spurious reactor trips.

Project Description A study to address overall aging and life limiting effects of instrumentation in the reactor protection and control systems has been completed. This study recommended a phased approach for possible hardware / systems replacement.

The main areas of concentration will be replacement of transmitters and main control board mounted equipment during the 1987 outage, and replacement of relay logic with solid state instrumentation in the 1989 outage.

CYAPCO Evaluation Modernizing the reactor protection and control system's instrumentation could increase the level of public safety by decreasing the frequency of spurious reactar trips and by increasing the reliability of the RPS. Further evaluation will be provided in the integrated assessment.

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Docket No. 50-213 B12197 Haddam Neck ISAP Topic No. 2.05 Process Computer Replacement September 1986

Haddam Neck ISAP Topic No. 2.05 Process Computer Replacement

Background

The Haddam Neck Plant process computer system has been a reliable aid to operators in the operation of the plant. It is, however, a system operating at its design limits. During peak loads, such as during a plant trip, it is common for data such as sequence of events information or equipment status changes to be lost because the system cannot handle the number of data changes or .their.

frequency. This information is useful in analyzing plant trips, and mitigating plant transients. Also, the present process computer system does not have the capability to support the installation of the safety parameter display system (SPDS).

Project Description The proposed project includes providing and installing a new Modcomp process computer complete with hardware and software to replace the existing IBM 1800 process computer at Haddam Neck. This new computer system .will be able to perform and enhance all current system functions by using state-of-the-art techniques (e.g., improved man-machine interface, use of CRT displays, increased scan rates, improved alarm processing, improved logging / trending capability, improved hardware /sof tware documentation, increased historical data retention). The new computer system will also be able to accommodate the SPDS.

CYAPCO Evaluation As the present computer is Operating at its design limits, CYAPCO plans to install the new process computer during the 1987 refueling outage, to improve upon the conditions discussed above as well as to support the installation of the safety parameter display system. However, further evaluation will be undertaken in the integrated assessment.

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