ML17319A573
| ML17319A573 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 08/18/1980 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17319A572 | List: |
| References | |
| NUDOCS 8009110584 | |
| Download: ML17319A573 (4) | |
Text
0 UNITEDsTATEs NUCLEAR REGULATORY'COMMISSION WASHINGTON, D. C. 20555 Docket Nos.
50-315 and 50-316 August. 18, 1 980 Mr. John
- Dolan, Vice President Indiana and Michigan Electric Company Post Office Box 18 Bowling Green Station New York, New York 10004
Dear Mr. Dolan:
We have completed our review of the Technical Specification requirements for the Rod Position Indication (RPI).
Our review was based on the information provided by Indiana and Michigan Electric Company in letters dated October 17,
- 1979, January 16, 1980 and June 17, 1980.
We'ave determined that you are in compliance with our requirements with regard to Control Rod Position Indication Systems at W stinghouse PWRs.
A copy of our evaluation is enclosed for your information.
i cerely,
Enclosure:
Safety Evaluation Report cN ~
even A+ Ver, Chf f
/Operating Reactors nch
- 1 Division of Licensing cc
w/enclosure See next page
.8
2
'!r.
',ohn Dol an Indiana and Michigan Elec.ric Company August 18,'980 cc:
i4ir. Robert ll. Jurgensen Chief Huclear Engineer American Electric Power Service Corporation 2 Broadway New York, Hew York 10004 Gerald Charnoff, Esquire Shaw, Pittman, Potts and Trowbridge 1800 H Street, H.V.
Mashington, D.
C.
20036 Citizens for a Better Environment 59 East Van Buren Street Chicago, Illinois 60605 fiaude Preston Palenske flemorial Library 500 l1arket Street St.
- Joseph, Nichigan 49085 l",r. D. Shaller, Plant ~lanager Donald C.
Cook Nuclear Plant P. 0.
Box 458 Bridgman, f)ichigan 49106 U.
S. Huclear Regulatory Corrmission Resident Inspectors Office 770 Red Arrow Highway Stevensvi lie, Michigan 49127 Milliam J. Scanlon, Esquire 2034 Pauline Boulevard Ann Arbor, Nichigan 48103
Encl osure SAFETY EVALUATION REPORT BY THE OFFICE OF NUCI EAR REACTOR REGULATION WESTINGHOUSE ROD POSITION INDICATION
~Back round The 'staff recently completed a review of the LER's and Technical Specification requirements related to the Control Rod Position Indication Systems (RPI} at Westinghouse PWRs and determined that a wide variation exists in the nurrber of LER's received and the Technical Specification requirements.
Discussion and Evaluation Westinghouse has performed safety analyses for control rod misalignment up to 15 inches or 24 steps (one step equals 5/8 inch).
Since analysis of misalign-ments in excess of this amount have not been submitted, we have imposed an LCO restricting continued operation with a misalignment in excess of 15 inches.
Because the analog control rod position indication system has an uncertainty of 7.5 inches (12 steps),
when an indicated deviation of 12 steps exists, the actual misalignment may be 15 inches.
This is because one of the coils, spaced at 3.75 inches, may be failed without the operator's knowledge.
The Stcndard Technical Specifications were written to eliminate any confusion about t:iis, and restrict deviations to 12 indicated steps.
Surveillance requirements, on the indication accuracy of 12 steps, were also prepared to ensure that t'~
15 inch LCO is met.
Since there is no difference intended in requirements issure for any Westinghouse
- reactor, plants with Technical Specifications written in different terms of misalignment should consider the 12 step instrument in-accuracy when monitoring rod position..
A related problem is that the installed analog control rod position indication system equipment may not, in some areas, be adequate to maintain, the control rod misalignment specification requirement because of drift problems in the calibration curves.
This is evidenced by numerous LER'sconcerning rod position indication accuracy.
In these
- cases, the uncertainty may be more than 12 steps.
Indiana and Michigan Electric Company was requested by letter dated October 29, 1979 to review the Technical Specifications for the D.C. Cook-Unit No, 1
8 2
'.o ensure that the control rods are required to be maintained with 12 stes indicated position and that the rod position indication system is accurate to within + 12 steps.
. The D.C.
Cook Unit Nos.
182 Technical Specifications require that the control rods are maintained within + 12 steps indicated position.
By letter dated March 19, 1979, the licensee requested a Technical Specification change that would explicitly allow for measurement of the LVDT coil stack voltages to verify rod position and eliminate the need for LER submittal due to faulty RPI readings.
In our October 29, 1979 letter we stated that the indicated (ROD) position requi rement of the current Technical Specifications can be fulfilled by the LVDT voltage measurements provided that a sufficient data base has been established.
In response to our October 29, 1979 by'etter the licensee in its letter dated January 16, 1980 stated that they agreed with our determination, however they still believe that their proposed Technical Specifications more clearly defined the action to be taken in the event the, RPI system should indicate a rod misalignment of greater than
+ 12 steps.
They further stated that measurements will be taken, as requi red during refueling outages for both units to obtain the necessary correlation between LVDT coil voltages and rod position.
By letter dated June 17, 1980 the licensee stated that the required measurements have been taken on both units of the Cook Plants to obtain the necessary correlation between LVDT coil voltages and rod position.
In addition the licensee stated that through discussion with members of the NRC staff they were informed that the proposed Technical Specification changes proposed in the March 19, 1979 letter were unnecessary, and therefore they were withdrawn.
Based on the licensees Technical Specification and the additional information submitted we find that the Technical Specifications are in compliance with our request and are 'therefore acceptable.