ML20211G487
| ML20211G487 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 02/18/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20211G484 | List: |
| References | |
| GL-83-28, NUDOCS 8702250401 | |
| Download: ML20211G487 (2) | |
Text
p ?.Et
'o UNITED STATES 4,
8 k
NUCLEAR REGULATORY COMMISSION E
WASHINGTON, D. C. 20555
\\*****/
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION CONCERNING REACTOR TRIP SYSTEM RELIABILITY GENERIC LETTER 83-28, ITEM 4.5.2 CONNECTICUT YANKEE ATOMIC POWER COMPANY DOCKET NO. 50-213 HADDAM NECK PLANT
1.0 INTRODUCTION
Generic Letter 83-28 was issued by NRC on July 8, 1983, indicating actions to be taken by applicants and licensees based on the generic implications of the Salem ATWS events.
Item 4.5 states a staff m sition which requires on-line functional testing of the reactor trip system, including independent testing of the diverse trip features of the reactor trip breakers, for all plants.
Item 4.5.2 requires applicants and licensees with plants not cur-rently designed to permit this periodic on-line testing to justify not making modifications to permit such testing. By letters dated November 3, 1983 and October 18, 1985, the licensee, Connecticut Yankee Atomic Power Company, responded to the staff position regarding Item 4.5.2 of Generic Letter 83-28, 2.0 EVALUATION The licensee states that the Haddam Neck Plant is not designed to allow
!l on-line testing of the reactor trip system (RTS). The Haddam Neck design does not include bypass breakers, which are necessary to permit on-line tripping of the reactor trip breakers without tripping the reactor. The licensee states that installation of the equipment required to modify the plant would be very difficult to accomplish because of the lack of space in the switchgear ronm, and that the Haddam Neck design provides simul-taneous operation of both shunt and undervoltage trip attachments. The licensee also states that maintainance and inspection of the reactor trip breakers revealed no indications of failure to trip during the past 19 years of operation, and that the RTS breakers are fail-safe since their control power is derived from the same 125 volt DC bus that supplies the control rod stationary grippers.
0702250401 870210 PDR ADOCK 05000213 P
~
3.0 CONCLUSION
The staff finds that the licensee's justification for not installing the modifications necessary to permit on-line testing of the reactor trip system at Haddam Neck is acceptable in view of (1) the cost and difficulty of installing the necessary equipment; (2) the fact that both the under-voltage and shunt trip attachments are actuated upon demand for reactor trips; (3) the fact that the reactor trip system breakers are fail-safe since their control power is derived from the same 125 volt D.C. bus that supplies the control rod drive stationary grippers; and (4) the satisfactory history of reactor trip reliability at the plant.
4.0 ACKNOWLEDGMENTS This Safety Evaluation was prepared by F. Farmer, INEL and A. Toalston, PAEI, DPWRL-A.
Dated: February 18, 1987 I
l I
I I
L