ML20006E063
| ML20006E063 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 02/12/1990 |
| From: | Chandu Patel Office of Nuclear Reactor Regulation |
| To: | Kovach T COMMONWEALTH EDISON CO. |
| References | |
| TAC-72728, NUDOCS 9002160183 | |
| Download: ML20006E063 (5) | |
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Fcbruary 12, 1990-I
. Docket No. 50-304 j
L Thomas J. Kovach
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. Nuclear Licensing Manager
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Commonwealth Edison Company-Suite 300 OPUS West III 1400 OPUS Place Downers Grove, Illinois; 60515
Dear Mr. Kovach:
i
SUBJECT:
ZION UNIT 2 - REQUEST FOR ADDITIONAL INFORMATION ON DEGRADED TUBE R1055INSTEAMGENERATORA(TACNO.72728) i By letter dated March 2,1989, Commonwealth Edison Company submitted a detailed assessment of degraded tube RIC55 in Steam Generator A of. Zion Unit 2.
This assessment was requested by the staff to ensure that this tube, which is plugged due to a circumferential crack, will not cause damage to adjacent tubes. We have reviewed your submittal and determined that additional information, as' identified in the enclosure, is needed before we can complete our evaluation. Please provide this information within 30 days from the date of this letter.-
The reporting and/or recordkeeping requirements contained in this letter i
affect fewer than ten respondents; therefore, OMB clearance is not required j
under P.L.96-511.
Sincerely.
Original signed by Chandu P. Patel, Project Manager Project Directorate 111-2 Division.of Reactor Projects - III, i
IV, Y and Special Projects Office of Nuclear Reactor Regulation
Enclosure:
As stated-p cc:.See next page W
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t February 12, 1990 Decket No. 50-304 Thomas J. Kovich Nuclear Licsuing Manager Connonwealth Edison Company-Suite 300 t
OPUS West III 1400 OPUS Place Downers Grove, Illinois 60515
Dear Mr. Kovach:
l
SUBJECT:
ZION UNIT 2 - REQUEST FOR ADDITIONAL INFORMATION ON DEGRADED TUBE RIC55INSTEAMGENERATORA(TACNO.72728)
By letter dated March 2, 1989, Commonwealth Edison Company submitted a detailed assessment of degraded tube RIC55 in Steam Generator A of Zion Unit 2.
This assessment was requested by the staff to ensure that this tube, which v
is plugged due to a circumferential crack, will not cause damage to adjacent tubes. We have reviewed your submittal and determined that additional information, as identified in the enclosure, is needed before we can complete our evaluation. Please provide this information within 30 days from the date of this letter.
The reporting and/or recordkeeping requirements contained in this letter affect fewer than ten respondents; therefore, OMB clearance is not required under P.L.96-511.
Sincerely.
hm/A O Chandu P. Patel, Project Manager Project Directorate 111-2 Division of Reactor Projects - 111 IV, V and Special Projects Office of Nuclear Reactor Regulation
Enclosure:
As stated cc: See next page t
- ~
Mr. Thomas J. Kovach Zion Nuclear Power Station Cosmonwealth Edison Company Units 1 ano 2 cc:
Robert J. Vollen. Esquire Mr. Michael C. Parker, Chief 109 North Dearborn Street Division of Engineering Chicago, Illinois 60602 1111pois Department of Nuclear Safety Dr. Cecil Lue-Hing 1035 Outer Park Drive. 5th Floor Director of Research and Development Springfield Illinois 62704 Metropolitan Sanitary District of Greater Chicago 100 East Erie Street Chicago, Illinois 60611 Phillip Steptoe, Esq.
Sidley and Austin One First National. Plaza Chicago, Illinois 60603 Mayor of Zion Zion, Illinois 60099 Illinois Department of Nuclear Safety ATTN: Nana'er, Nuclear Facility Safety 1035 Outer l ark Drive. 5th Floor Springfield. Illinois 62704 U.S. Nuclear Regulatory Cosmission Resident Inspectors Office 105 Shiloh Blvd.
Zion, Illinois 60099 Regional Administrator, Region III l
U.S. Nuclear Regulatory Commission 799 Roosevelt Road, Bldg. f4 Glen Ellyn, Illinois 60137 l
l
1 ENCLOSURE I
REQUEST FOR ADDITIONAL INFORMATION COMMONWEALTH EDISON COMPANY ZION UNIT 2 DEGRADED TUBE R1055 IN STEAM GENERATOR A
Reference:
Connonwealth Edison letter dated March 2,1989, to Director of Nuclear Reactor Regulation, NRC, with enclosed Westinghouse Report WCAP-12175.
j 1.
Section 5.2 of WCAP-12175 briefly describes the qualification of the analytical turbulence excitation model using a prototypical two-phase test. PleasedescribehowFASTVIB(seeSection6.1)wasqualifiedto calculatefluidelvticstabilityratiosforprototypicaltwo-ghase What is the expected accuracy (in terms of +/
"x percent) conditions.
of the turbulent response model and the FASTVIB model for prototypical conditions?
2.
Provide an assessment of the uncertainty associated with the stability ratio results in Table 6-1 which is introduced by uncertainties in the assunied damping coefficient and stability constant and by the uncertain-ties in the ATHOS flow velocity, density, and void fraction distribution results.
3.
Considering the scenario of a severed tube discussed in Section 6.4, confirm that the Westinghouse model considered the u-bend segment extending (from the severed location to the top support on the hot leg side rather than sim)1y the shorter u-bend segment extending from the severed location to tie top support on the cold leg side).
I 4.
The staff notes that, dependent on the actual crossflow velocity distri-bution, a tube may initially undergo instability in a mode other than the lowest frequency mode. Has Westinghouse calculated the modal effective velocity (MEYEL) and associated stability ratio for several of the lowest modes, or only the lowest mode? Do the results given in Table 6-1 corres-pond to the lowest mode?
5.
Clarification of note (3) of Table 6-1 is requested.
For example, when the authors state " Actual U-bend values would be lower than the values listed for this case", are they referring to all the values or only the values for stability ratio and turbulent displacement?
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6.
"The linearly supported tube" (p. 35) was used for the fluidelastic in-l stability analysis, while " nonlinear, finite element, dynamic methods" (p. 37) were used for the turbulence response of U-bends. Why were two different models used?
l 7.
On page 38, the equation for the response to turbulence excitation is independent of damping.
Is the effect of damping included in the para-meter C 7 3
8.
There are errors in Eq. (1) [d is missing in the numerator of the right-hand-side) Eq. (2) [the slash (/) symbol in the denominator of the right-hand-side should be deleted), and the equation on page 38 [should be subscript o on P rather then superscript og should be A2 in denominator 4
i ofright-hand-side].
In the nomenclature given on page $6, n is omitted, j
9.
The staff believes it would be prudent to inspect the tubes adjacent to RICSS as part of each inservice steam generator tube inspection in or6er to confirm the analysis prediction that damage to these tubes is not occurring.
Please discuss your plans in this regard.
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