ML20056F772
| ML20056F772 | |
| Person / Time | |
|---|---|
| Site: | Ohio State University |
| Issue date: | 08/23/1993 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20056F770 | List: |
| References | |
| NUDOCS 9308310038 | |
| Download: ML20056F772 (2) | |
Text
.
peatcy
- 'o UNITED STATES !
8' ),c'j NUCLEAR REGULATORY COMMISSION g .E WASHINGTON, D. C 20555 o ?
\.'...+/ k i
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 14 TO FACILITY OPERATING LICENSE N0. R-75 OHIO STATE UNIVERSITY I i
DOCKET N0, 50-150
1.0 INTRODUCTION
By letter dated May 5, 1993, Ohio State University (the licensee) requested that their Technical Specifications (TS) be revised to allow greater magnet holding currents in the control rod magnet circuits before rod drops are initiated. Rod drops are presently initiated when the magnet holding currents ,
equal or exceed 60 milliamperes (ma). The licensee has requested that rod i drops not be initiated until the magnet currents equal or exceed 100 ma. The '
licensee has requested this change in order to avoid dropping the adjacent control rod when performing rod drop tests. At the present setting of 60 ma, 1 the adjacent rod drops because it is mounted on a common beam support l structure, and the mechanical vibration is greater than the magnets holding power at 60 ma.
t 2.0 EVALUATION l The control rods are released above a certain magnet current setting because i of a possible short in the magnet circuit. The current setting at which the ;
rods are released, however, does not have any safety significance as long as the magnet circuit is rated for the current setting. The magnet circuit is capable of handling 100 ma.
i However, the higher the holding current before the rods are released results in an increase in the drop time of the rods, which is specified by TS to be 600 milliseconds (ms) (TS 3.2.1). The licensee conducted tests at various rod heights and at various holding currents for the three shim rods, which are ,
documented in the May 5, 1993 submittal.
1 The maximum insertion time occurred for shim safety rod #3 (SSR3) which for a 60 centimeter drop was 500.1 ms. This drop time provides a 99.9 ms margin from the required 600 ms drop time and is adequate. The maximum increase in -
drop time between the 60 ma and the 100 ma settings also occurred for SSR3 and was 10.7 ms, which amounts to a 2.2% increase over the 60 ma setting. The staff finds that the release currents for the shims safety rods can be increased to 100 ma.
l T
9308310038 930823 0-PDR ADOCK 0500 P
3.0 ENVIRONMENTAL CONSIDERATION
This amendment involves changes in the installation or use of facility '
components located within the restricted area as defined in 10 CFR Part 20.
The staff has determined that the amendment involves no significant increase i in the amounts, and no significant change in the types, of any effluents that l may be released offsite, and there is no significant increase in individual or cumulative occupational radiation exposure. Accordingly, this amendment meets ,
the eligibility criteria for categorical exclusion set forth in 10 CFR ,
51.22(c)(3). Pursuant to 10 CFR 51.22(b), no Environmental Impact Statement or Environmental Assessment need be prepared in connection with the issuance of this amendment.
4.0 CONCLUSION
i The staff has concluded, based on the considerations discussed above, that: !
(1) because the amendment does not involve a significant increase in the probability or consequences of accidents previously evaluated, or create the l possibility of a new or different kind of accident from any accident !
previously evaluated, and does not involve a significant reduction in a margin l of safety, the amendment does not involve a significant hazards consideration, (2) there is reasonable assurance that the health and safety of the public util not be endangered by the proposed activities, and (3) such activities I will be conducted in compliance with the Commission's regulations and the ;
issuance of this amendment will not be inimical to the common defense and ,
security or the health and safety of the public. !
Principal Contributor: Theodore S. Michaels i Date: August 23, 1993 [
t i ,
2 l
I i
l
}
,