View source for U-600187, Submits Addl Justification to Support 850416 & 0524 Requests for Exemption from Current Piping Design Criteria Re Arbitrary Intermediate Pipe Breaks

{{Adams
| number = ML20128F541
| issue date = 07/03/1985
| title = Submits Addl Justification to Support 850416 & 0524 Requests for Exemption from Current Piping Design Criteria Re Arbitrary Intermediate Pipe Breaks
| author name = Spangenberg F
| author affiliation = ILLINOIS POWER CO.
| addressee name = Butler W
| addressee affiliation = NRC OFFICE OF NUCLEAR REACTOR REGULATION (NRR)
| docket = 05000461
| license number = 
| contact person = 
| document report number = U-600187, NUDOCS 8507080267
| document type = CORRESPONDENCE-LETTERS, INCOMING CORRESPONDENCE, UTILITY TO NRC
| page count = 2
| project = 
| stage = Other
}}

=Text=
{{#Wiki_filter:U- 600187 L30-85(07-03)- L
     .                                                          1A.120 t /LLINDIS POWER 00MPANY IP   CLINTON POWER STATION, P.O. BOX 678. CLINTON. ILLINOIS 61727 July 3, 1985 Docket No. 50-461 Director of Nuclear Reactor Regulation Attention: Mr. W. R. Butler, Chief Licensing Branch No. 2 Division of Licensing US Nuclear Regulatory Commission Washington, DC 20555

==Subject:==
Clinton Power Station Unit 1 Elimination of Arbitrary Intermediate Pipe Breaks

==Dear Mr. Butler:==

In Letters U-0832 dated April 16, 1985 and U-600070 dated May 24, 1985, Illinois Power Company submitted requests for exemption from current piping design criteria with respect to arbitrary intermediate pipe breaks for Clinton Power Station. This letter provides additional justification to support the previous submittals regarding thermal cycling and thermal mixing at branch connections for the breaks under consideration.
The normal stress effects of rapid changes in temperatures c,f process piping are accounted for in the ASME Section III, Class 1 fatigue analyses. Thermal mixing and stratification usually occur where fluids of significantly higher or lower temperatures are injected at branch connections. The intermediate breaks specified in the original request consist of breaks where temperatures are uniform and no injections of fluid occur.
The reactor recirculation branch connections, as shown in Appendix A of the {{letter dated|date=April 16, 1985|text=April 16, 1985 letter}}, are examples of this. No thermal mixing and, hence, no resulting thermal fatigue is expected to occur in the branch connections to the ring header since there is no large source of cold water in the Clinton (BWR/6) design. Unlike earlier BWR designs, neither the Emergency Core Cooling Systems nor the Residual Heat Removal systems introduce cold water into the recirculation loop. Thus, no significant thermal cycling is expected due to mixing in this system.
l Illinois Power Company believes that this supplemental information l
should provide the necessary justification to support the original I        request. A prompt reply is requested to maximize the benefits of this proposed change to the pipe break criteria.
I*
  !WWewq

U- 600187 L30-85 (07- 03)- L 1A.120 Please contact us if you have any questions regarding this matter.
S neere             ours, eY l F. A Span             ber Dir tor              ucle             Licensing
,                                                                            and Configuration Nuclear Station Enginecring JLP/ lab cc:   B. L. Siegel, NRC Clinton Licensing Project Manager NRC Resident Office Illinois Department of Nuclear Safety Regional Administrator, Region III, USNRC t
                          -   ,n ,,- - - -,, -,, - ,--- .- - - - - - + - .                   -       - - - - - , , - - , ,}}