ML19294C131
| ML19294C131 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 01/23/1980 |
| From: | Hoffman D CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| Shared Package | |
| ML19294C124 | List: |
| References | |
| NUDOCS 8003060763 | |
| Download: ML19294C131 (4) | |
Text
..
J COnSumBIS Power Company Generet CWilces: 212 West Michtgen Avenue. Jackson, Michleen 49201 + (517) 7884550 January 23, 1980 Mr James G Keppler Office of Inspection and Enforcement Region III US Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, IL 60137 DOCKET 50-155 - LICENSE DPR BIG ROCK POINT PLANT - CONSUMERS POWER COMPANY COMMENTS ON IE INSPECTION REPORT #79-14 DATED DECDiBER 20, 1979
Reference:
Letter Dated December 20, 1979 From G Fiorelli of the hegion III Reactor Construction and Engineering Support Branch to D P Hoffman Enclosed please find Consumers Power Company's reponse to concerns raised by Mr I T Yin during his inspection conducted November 6-7, 1979 at Big Rock Point Plant and November 15-16, 1979 at the Bechtel Associates Professional Corporation. Mr Yin's concerns were brought out in his inspection report dated December 18, 1979 (see reference). However, in hi. Inspection Summary he states, "No items of noncompliance or deviations were identified."
Consumers Power Company was requested to address Mr Yin's concerns. The enclos.re does this and Consumers Power Company considers the issue closed.
David P Hoffman Nuclear Licensing Administrator CC Director, Office of Nuclear Reactor Regulation Director, Office of Inspection and Enforcement
Attachment:
BRP Response for December 20, 1979 Region III Inspection Report (3 Pages)
- Rh gW' 8cesoGo762
4 BIG ROCK POINT PLANT RESPONSE FOR DECEMBER 20, 1979 REGION III INSPECTION REPORT The following responses are made in reference to Big Rock Point December 20, 1979 Region III Inspection Report regarding IE Bulletin 79-14.
Our responses address only the specific concerns of your inspector as shown in Paragraph 3, IE Bulletin 79-14 Inspection (b) Design Review at Bechtel Associates Professional Corporation (BAPC).
The specific concerns are addressed as follows:
1.
The Santac Nuclear Corporation (SNC) seismic analysis for the Reactor Depressurization System (RDS) was considered invalid because the one 12" main steam to turbine and the two 6" steam to emergency condenser lines that connect to the 12" RDS line were ignored in the analysis.
Response
The SNC seismic analysis for the RDS was limited to only that system.
RDS was conservatively designed to criteria then applicable to new plants. The design earthquake and the analysis method (dynamic rather than static) were considerably more conservative than the original plant design. The RDS was raodeled showing the RDS rigidly supported at the point where it connects to the main steam piping (which contains the 12" main steam and two 6" emergency condenser piping connections).
The technical judgment used in design and seismic analysis was that the RDS piping should not load the main steam piping.
In effect, the RDS and main steam piping act together as a flexible system. The assumed anchor point provides conservative stresses in the RDS piping and served to divorce the old piping (and criterie) from the new piping (and criteria).
Based on the above, there is no doubt that the entire system (RDS plus main header) meets the old criteria.
Recently, CP Co has had the primary coolant system modeled by D'Appolonia for the purpose of performing SEP seismic analysis. Their conclusion was also that the main steam header and connecting RDS piping are a flexibile system which moves independently, although probably partially driven by the primary system (heavy drum).
At this time, CP Co judges that the RDS analysis is valid and conservative both with respect to the model and the assumed seismic input.
In any event, this piping is being analyzed as a part of the SEP seismic topic which will provide a consistent analysis for the entire system to a common approved criteria.
2.
The SNC valve analysis was considered invalid because of the lack of justification for using the formula:
F = (K + 0.2) AP.
Response
The SNC relief valve analysis which uses an equation published in an article, " Piping of Pressure Relieving Devices" by L R Driskell was compared by our architect engineer (Bechtel) to an equivalent equation used in Bechtel's Topical Report BN-TOP-2 Rev 2.
The comparison of the
2 i
two equations shows the equation published in an article, " Piping of Pressure Relieving Devices" by L R Driskell will generate higher steady state reaction forces than the forces generated using the BN-TOP-2 Rev 2 equation.
Consequently, C!
-o concludes the equation published in an article, " Piping of Pressure Relieving Devices" by L R Driskell is conservative for our purpose.
2a.
The load components associated with the blowdown event were judged by I T Yin to be improper because the horizontal force component perpendicular to the steam drum enclosure wall was ignored, whereas the vertical and the horizontal component parallel to the steam drum enclosure wall was considered.
Response: Recent discussions with Catalytic /Suntac revealed the following: The blo down leads were generated from a 1365 psi transient initiated at valve opening. At the target rock valves (SV4984, SV4985, SV4986, SV4987), three forces exist due to the blowdown event. Two of these forces (vertical and parallel to the steam drum enclosure wall) are unbalanced. The north-south (perpendicular to the steam drum enclosure wall) is balanced in that a similar force opposite in direction exists at the three tee runs and at the 6" elbow. This balanced force is comparable to a static pressure which at 1365 psi is less than the 1700 psi used in deadweight calculations.
The balanced force is thus ignored as noncontrolling and defers to the design pressure in application to equations of NB3653 - NB3655.
The unbalanced forces are added as a separate loading.
2b.
The geometry of the downcomer piping as it enters the steam drum enclosure is not in a north-south plane.
It does have three directional components with respect to the global coordinate system.
Therefore, the two-directional reaction forces used in the analysis are not a proper characterization of the field as-built conditions.
Response: Recent discussions with Catalytic /Suntac revealed the following: The analysis is consistent with the drawings.
The field as-built conditions implies that they are both wrong.
The east-west pipe direction component implies the existence of an east-west blowdown force component. The force component is very small and is reacted by the pipe supports above the bends; consequently, no problem exists.
Blowdown stresses in the pipe are very small as well.
3.
The design loadings for seismic and relief valve lift restraints on the RDS were not shown in the SNC calculations and the valves were not included on the hardware installation drawings. The validity of the restraint setting and the adequacy of the supporting structures could not be verified or evaluated.
Response
It is CP Co's conclusion that the design loadings for seismic and relief valve lift restraints do not have to be shown on the hardware installation drawings. The validity of the restraint setting and the adequacy of the supporting structures can be verified or evaluated in the Pipe Support Calculation Report RDS-PS-36 dated 3/5/75 which is a part of
3 s
the RDS package for Big Rock Point Plant.
CP Co feels no further action is necessary.
It is concluded that the above responses will resolve the specific concerns of Mr'I T Yin, Region III Inspector, and satisfy the intent of IE Bulletin 79-14 for Big Rock Point.
It is further reiterated that CP Co has already committed to a seismic evaluation program under SEP for Big Rock Point Plant, whereby piping systems including the RDS will be reviewed again.