ML18052A235
| ML18052A235 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 01/14/1986 |
| From: | Berry K CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8601210395 | |
| Download: ML18052A235 (2) | |
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consumers Power company General Offices:
1945 West Parnall Road, Jackson, Ml 49201 * (517) 788-1636 January 14, 1986
- Director, Nuclear Reactor Regulation US Nuclear Regulatory Commission Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT -
-TECHNICAL SPECIFICATIONS CHANGE REQUEST -
SNUBBER DRAG FORCE ACCEPTANCE CRITERIA - ADDITIONAL INFORMATION Kenneth W Berry Director Nuclear Licensing Consumers Power Company submitted the subject Technical Specifications Change Request on January 10, 1986.
The following information is to support the issuance of a Palis.ades license amendment, in accordance with the emergency situation provisions in 10CFR50.9l(a)(5).
Failure to issue the Amendment in a timely manner will result in an extension of the. Palisades refueling outage beyond the predicted on-line date.*
The proposed Tec.hnical Specifications Change affects the acceptance criteria for the seven mechanical snubbers listed in Table 3.20.2.
One of the snubbers, SNB-68, located on a Safety Injection System line to Tank 82B, was removed in December and sent to Wyle Labs, Huntsville, Alabama, for functional testing in accordance with Technical Specification 4.16.1.e.l.
The specifi-cation requires:
"The force that initiates free movement of the snubber rod in either tension or compression is less than the specified maximum drag force (break away friction) which is equal to 1% of the rated load."
The results of the testing conducted on December 31, 1985 revealed that the 1%
value was exceeded in three of the six tests.
For the 6000 lb rated snubber, a drag force value of 60 lbs (1%) would have been acceptable.
The test results exceeding the 60 lb drag force limit were:
62.4 lbs in tension, and 66 ~bs an<l: 79_.2lb_i:i,in compression.
The basis.for the maximum drag*force value being 1% of rated load is found in the vendor, ITT Grinnell, Maintenance and Installation Manual and reiterated in a Bechtel Field Instruction.
The 1% value, however, was found to be overly conservative when compared to the manufacturer's, Pacific Scientific, design specification which stated the drag force should not exceed 2% of rated load.
Verbal confirmation of the 2% value from Pacific Scientific has been obtained.
All seven mechanical snubbers in the Technical Specification Table 3.20.2 are manufacturered by Pacific Scientific.
OC0186-0007-NL02.
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Director, Nuclear Reactor Regulation Palisades Plant Additional Information -
TSCR January 14, 1986 2
Following the functional test, when the snubber failed to meet the drag force acceptance criteria of 1% of rated load, Consumers Power Company made the decision to pursue relief from the overly restrictive 1% value, as it was known at that time that 2% was a widely accepted value and drag force is not a parameter used in the analytical models to determine the piping support system.
The snubber SNB-68 was returned to Palisades.
On January 2, 1986, plant management was notified of the problem and calls were made to both NRC Region III and NRR seeking guidance on the proper course of action.
On January 7, it was agreed with the NRC Palisades Project Manager that a Technical Specifications Change was necessary.
Consumers Power then proceeded to process the reviews and approvals for the change request which, again, was sent January 10, 1986.
The presently predicted day to begin plant heatup is January 27, 1986.
The snubber and the safety injection system will have to be operable prior to bringing the reactor critical on February 1, 1986.
The decision to pursue a Technical Specifications Amendment instead of modifying or replacing the snubber and conducting another functional test of it and another snubber (Technical Specification 4.16.lc requires an additional 10% sample if acceptance criteria is not met) was made due not only to the overly restrictive acceptance criteria, but also because the additional work would be required during the outage. Furthermore, because of the. nature of the mechanical snubber, refurbishment was determined to be difficult and a new snubber would have to be procured as a replacement.
This would have imposed additional and unnecessary work during the outage.
The Technical Specifications Change is therefore considered to be warranted, does not involve an unreviewed safety question, and involves no significant hazards consideration because it is based on a manufacturers recommended value for the acceptance criteria.
Consumers Power Company requests that action to issue a license amendment under the emergency situation provisions of 10CFR50.9l(a)(S) be done in a timely manner such that it will not affect plant startup.
Kenneth W Berry Director, Nuclear Licensing CC Administrator, Region III, USNRC NRC Resident Inspector - Palisades OC0186-0007-NL02