ML20071E489
| ML20071E489 | |
| Person / Time | |
|---|---|
| Site: | Midland |
| Issue date: | 02/25/1983 |
| From: | Jackie Cook CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, 20713, 78-05-12, 78-5-12, MCAR-22, NUDOCS 8303100263 | |
| Download: ML20071E489 (6) | |
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Consumers Power Company f;"*L'* 'l _ ~j,,,o.,,,,~,,,
and Construction General offices: 1945 West Parnall Road, Jackson, MI 49201 e (517) 78&O453 February 25, 1983 78-05 #12 Mr J G Keppler, Regional Administrator US Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn, IL 60137 MIDLAND NUCLEAR C0 GENERATION PLANT DOCKET NOS 50-329 AND 50-330 REACTOR BUILDING SPRAY PIPING SUPPORTS FILE:
0.4.9.17 SERIAL: 20713
Reference:
(1) CPCo (S H Howell) letter to NRC (J G Keppler), Same Subject, Serial Howe-320-79, Dated December 21, 1979 Referen e 1 had provided Consumers Power's final report on the subject of Reactor Building Spray Piping Supports. On 1/25/83, W R Bird informed R Gardner of your staff that we were going to reopen the 50.55(e) report because of possible unconservative water hammer loads being used in the original design analysis. Mr Gardner had confirmed that NRC had not as yet closed out 78-05.
Attached is Interim Report 1 to MCAR-22 Addendum which provides a complete description of the concern and the status of the actions being taken to resolve the concern.
Another report, either interim or final, will be sent on or before July 11, 1983.
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Attachment:
MCAR-22 Addendum, Interim Report 1, dated February 16, 1983 CC: Document Control Desk, NRC Washington, DC RJCook, NRC Resident Inspector Midland Nuclear Plant 8303100263 830225
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PDR ADOCK 05000329 S
PDR OC0283-0019A-MP0 MAR 71983
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Serial 20713 78-05 #12 L
CC: CBechhoefer,-ASLB Panel FPCowan, ASLB Panel JHarbour, ASLB Panel AS&L: Appeal Panel MMCherry, Esq MSinclair BStamiris CRStephens, USNRC WDPaton, Esq. USNRC FJKelley, Esq, Attorney General SHFreeman, Esq, Asst Attorney General WHMarshall
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Attachment to 1053*4 seria1 20713 Bechtel Associates ProfessionalCorporation Ta_e na
SUBJECT:
MCAR 22 (Addendum issued 1/26/83)
Reactor Building spray Anchors INTERIM REPORT 1 DATE:
February 16, 1983 PROJECT:
Consumers Power Company Widland Plant Units 1 and 2 Bechtel Job 7220 Description of Deficiency A modeling assumption was discovered in the original reactor building spray
"' system water hammer analysis', which resulted in less conservative results.
Some_of the recalculated water hammer pressures are higher than those calculated in the original analysis.
Summary of Investiaation Bechtel has recalculated the pressure time histories for the reactor building spray system header usi,ng revised modeling assumptions. The maximum differential pressures in each spray header piping branch have changed in magnitude from -30 to +275% from the values originally calculated (see Table 1).
The pressure time histories are currently being converted to force time histories for input to the piping stress analysis.
Analysis of Safety Implication The primary safety-related functions of the reactor building spray system are
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to remove sensible heat and subsequent decay heat from the reactor building and to remove fission' products from the reactor building atmosphere following loss of coolant or main steam.line break accidents. The piping stress
' analysis and associated hanger and anchor design provides assurance that the j
reactor building spray header will remain intact to parform these safety l
' functions. The calculation of the water hammer forces in the reactor building spray header'.is one input' to the stress analysis. The final disposition of MCAR 22. Reactor Building Spray Anchor Discrepancy, was based on the original reactor building spray header stress analysis completed in 1979. The increased water hammer loads put the design of the spray header in question until the stress' analysis is completed and hanger design can be verified.
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Bechtel Associates Professional Corporation 4
105361 NCAR 22 Interim Report 1 Page 2 i
Probable Cause i
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'This discrepancy was caused by simplifying.modeling assumptions made in the original water hammer analysis that appeared reasonable at the time but were j
subsequently found to be less conservative in certain cases.
i Corrective Actions The following actions have been initiated.
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1.
Verification of the Installed Plaint. Hanmer. and Anchor Desian i
Bechtel has recalculated new water hammer pressure time histories for the i
spray header and is currently converting these pressure time histories into force time histaries. The fo~rce time histories will be input into j
the piping stress shalysis to develop loading forces on piping hangers and
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i anchors. The installed design of the piping, piping hanger, and anchors will then be evaluated by Bechtel for compliance with ASME Code allowables.
2.
Determination that the Modelina Assumptions In Ouestion Were Not Used in j
Other Water Hammer Analyses on the Midland Proiect A summary of the modeling assumptions and their use has been distributed I
to other Bechtel AAO project and staff entities performing' water hammer analyses for assessaient of' applicability to their work.
The basis for the probable cause. involves engineering judgment and decisions and is not associated with a deficiency in engineering procedures or practices. Therefore, no process corrective action is required.
A schedule for completion of the above corrective actions will be provided in the next interia report.
j Reportability Because of the indeterminate nature of the impact on plant safety, this item i
has been conservatively considered to be pot'entially reportable considet ng criteria. contained in 10 CFR 50.55(e). Consumers Power Company reported this condition to the NRC on January 25, 1983.
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105361 NCAR 22 3
Interim Report 1 Page 3 W & g* & a Submitted by:
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J.K. Clements Nuclear Systems Group Super-visor O
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Approved by.
ILw it.dd E'M. Hughes ProjectEngineer(
Concurrence by:
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R.B. Fallgrengf Geotechnical Services Manager Concurrence b d4 (.
4 f t. Loos Chief Nuclear Engineer Concurrence by:
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E.H. Smith "
Engineering Manager Concurrenceby[:
M.A. Dietrich
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1.05334 Bechtel Associates Professional Corporation 10536l MCAR 22 Interim Report 1 Page 4 TABLE 1 REACTOR BUILDING SPRAY HEADER DIFFERENTIAL PRESSURES Reactor Building Spray Maximus Differential Header Pipe Number and Pressure (ft of water)
Percent Quadrant Orizinal Analysis Revised Analysis Chanted 1GCB-12. Quad 1 1,190 840
-30 1GCB-12. Quad 2 1.190 840
-30 1GCB-10, Quad 1 508 540
+6 1GCB-10, Quad 2 508 600
+18 1GCB-8, Quad 1 570 740
+30 1GCB-8, Quad 2 570 1,210
+112 1GCB-6, Quad 4 1,068 980
-8 1GCB-6, Quad 3 1,068 940
-12 1GCB-2, Quad 4 962 860
-11 1GCB-2, Quad 3 962 990
+3 1GCB-4, Quad 4 616 750
+22 1GCB-4, Quad 3 616 2,310
+275 i
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