ML20062F886
| ML20062F886 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 11/20/1990 |
| From: | Beckman W CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9011280243 | |
| Download: ML20062F886 (2) | |
Text
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b Oe*0WERING i
Consumers POWB[
William L Deckman Plant Manager MKNeGAN'S PROGRES%
Big Rock Point Nuclear Plant,10269 US 31 North, Charlevoix, MI 49720 November 20, 1990 i
Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 DOCKET 50-155 - LICENSE DPR BIG ROCK POINT PLANT -
INTEGRATED PLAN ISSUE BN-014A, RESOLUTION OF SEISMIC ISSUES, SCHEDULE CHANGE This letter provides notification of a schedule change to Big Rock Point Integrated Plan Issue BN-014A, Resolution of Seismic Weak Links.
Issue BN-014A was scheduled for completion during the 1990 Refueling Outage, this schedule will not be met. A revised schedule for Issue BN-014A will be reported in the next Integrated Plan Semi-Annual Update. An Issue BN-014A status update is provided below.
Factors that have contributed to not meeting the reheduled completion date (1) Delays in consultant cupport, (2) Reallocation of corporate engineer-are:
i ing resources to support the Palisades Plant IE Bulletin 79-14 Project and_the Palisades Steam Generator Replacement Projact, and (3) Consideration of expansion to the project scope to include unanticipated minor modifications.
If the changes in project scope described below become necessary, they will be submitted to the Technical Review Group (TRG) for ranking and scheduling.
The scope of Issue BN-014A is to perform an evaluation to determine the seismic capacity of the emergency condenser slell supports.to comply with a seismic demand of up to 0.12g at the established safe shutdown earthquake (SSE). The evaluation is also to 1: lude three masonry blockwalls, M10020, M10021, and M10023.
By upgrading the identified weak links the already low probability of seismic induced core damage is further reduced.
The current status of Issue BN-014A is as follows:
ENGINEERING ANALYSIS OF BLOCKWALLS M10020. M10021, M10023 The 3-D non-linear analysis of the blockwall seismic capacity is nearing completion.
Preliminary results indicate that the current blockwall boundary condition assumptions are not sufficient to qualify the wall :to 0.12g.
New boundary conditions (i.e., new support anchoring for the to;-
~ the walls) are the likely recoumended resolution in the wall qualification prc.ess.
These modifications to the walls were not anticipated nor estimate:d in the scope for BN-014A resolution.
The modifications should be minor in nature and would OC1190-0008A-QA02 9011280243 901120
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Big Rock Point Plant Integrated Plan Issue BN-014A November 20, 1990 k
j primarily consist of angle iron along the upper boundary, and clips or-through-i bolts to the existing structural steel framework in the vicinity of each wall.
These modificat$ons, should they be necessary, would not require an outage and would be submitted to the TRG for ranking and scheduling.. Completion of the 3-D analysis is anticipated shortly after the.1990 Refueling Outage.
As an additional note, a recent review of Consumers Power Company-letter' dated i
August 29, 1988, entitled, Integrated Plan Issue BN-014A Update, revealed a-typographical error in Table VIII-5.
Blockwall M10018 was listed as 0.12g and blockwall M10020 was listed as 0.13g.
These two wa.11s should be switched.
EMERGENCY CONDENSER SHELL SUPPORTS The proposed upgrade for the Emergency Condenser has been submitted toL a consultant for seismic capacity analysis and a modification necessity determination. The analysis is not yet complete, however, the preliminary indication is that the Emergency Condenser may already have adequate capacity to resist seismic loads up to 0.12g and that-if any modifications are-necessary, they will be minor in nature. The analysis is estimated to be complete shortly after the 1990 Refueling Outage. A schedule-for completion for any Emergency Condenser modifications will be developed upon receipt of the consultants final report.
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Wil-li L Beckman Plant Manager l
CC Administrator, Region III, USNRC NRC Resident Inspector - Big Rock Point r
OC1190-0008A-QA02-
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