ML20085H609
| ML20085H609 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 08/19/1983 |
| From: | Woolever E DUQUESNE LIGHT CO. |
| To: | Murley J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, 2NRC-3-063, 2NRC-3-63, 83-08, 83-8, NUDOCS 8309120165 | |
| Download: ML20085H609 (3) | |
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" Pap 2NRC-3-063 (412) 787 - 5141 Telecopy
-6 Nuclear Construction Division August 19, 1983 Robinson Plaza, Building 2, Suite 210 Pittsburgh, PA 1E205 United States Nuclear Regulatory Commission Region I 631 Park Avenue King of Prussia, PA 19406 ATTENTION:
Dr. Thomas E. Murley Administrator
SUBJECT:
Beaver Valley Power Station - Unit No. 2 Docket No. 50-412 Heavy Wall Thickness on Diesel Generator Exhaist System Significant Deficiency Report No. 83-08, Interim Report No. 2 Gentlemen:
This is the second Int e rim Report in reference to the pot ent ially repo rt ab le Significant Deficiency rela t ing to the use of nominal wall thickness of fittings to determine the weight used as design input to stres s calcula t ions. An evaluation is currently underway to determine the impact of the thick wall fittings on the diesel generato r exh au s t piping sys t em.
Pursuant to the requireme nt s of 10 CFR50.55(e), it is ant icipa ted that a s ubseque nt report on this matter will be submitted to Region I by October 28, 1983.
DUQUESNE LIGHT COMPANY s
By Nf
~ Elf J."Wooleve r Vice President c
JS/wjs At tachment cc:
Mr. R. DeYoung, Director Of fice of Inspection and Enforcement (3) (w/ attachment)
Mr. G. Walton, NRC Resident Inspector (w/ attachment) l Ms. L. Lazo, Project Managaer (w/ attachment)
NRC Document Control Desk (w/ attachment)
INPO Records Center (w/ attachment) i l
I t
8309120165 830819 PDR ADOCK 05000412
BEAVER VALLEY POWER STATION UNIT NO. 2 DUQUESNE LIGHT COMPANY Repo rt on Potential Significant Deficiency No. 83-08
" Heavy Wall Thickness on Diesel Generator Exhaust System" 1.
SUMMARY
During a routine safety ins pect ion by the NRC resident ins pe ct o r, the emergency diesel generator exhaust piping (spools EDG 3-1 and EDG 14-1) were found to have thicknes s reading s of 0.7 5",
which is twice their nominal value.
This was cited as an Item of Violation in Inspection No.
50-412/83-07.
Since that time, Interim Report No. 1 (2HRC-3-054, dated July 28, 1983) was issued by Duquesne Light.
2.
IMMEDIATE ACTION TAKEN Mr.
E.
F.
- Kurtz, Jr.,
Manage r of Duquesne Light Cm pany's Regula to ry Af fairs Department, notified Mr. Lowell Tripp of the NRC Region I of fice on June 27, 1983, on this pot ent ial ly repo rt ab le de fici ency.
An engi-neering evalua t ion is underway to determine the repo rt abili ty status of the exhaust piping system.
3.
DESCRIPTION OF DEFICIENCY (Ext ract ed from NRC Ins pe ct io n Repo rt 83-07 dated June 10, 1983)
In the diesel generator exhaust system, two spools EDG-3-1 and EDG-14-1, while being installed were found to have thickness measurement s of 0.75" which is twice the 0.375" nominal wall.
The system contains 1-90
- long radius Ell, 2-45* Ell's, 1-38 inch s t anda rd tee, 1-38 inch flange, and 2-38 inch standard pipes.
The fittings were ordered from Ladish Capany as 38 inch s t anda rd (0.375 nominal wall).
The actual wall thicknes s me asurement s pe rfo rmed by site quality control by req ue s t of the NRC, found the 90* elbow, the 2-45' elbows, and the one tee to have an average wall thic knes s of 0.750 inch.
The s tr es s calcula t ions fo r this sys tem were based on the nominal wall thickness.
4.
ANAL' SIS OF SAFETY IMPLICATIONS The specific problem of heavy wall fittings was ident ified prior to com-ple t ion of the final design of the sys tem and rela t ed su ppo rt s.
Pipe stress calcula t ion nn. 12241-NA(T)-XG0K-1 pr oduced piping react ions on the emergency diesel ge nera to r exhau s t silence r 38" nozzle wh ich were s ummarized in equipment nozzle loads, as req ui red bi 2 BVM-4 5.
This calculation was marked " confirmation required" and noted that "the manu-factures' allowab les were not ava ilab le" and that the calcula ted loads included are to be approved by the manufacture or are to be "adeq ua tely demonstrated that nozzle loadings will not adversely af feet the operation of the equipment thru calcula t ions, t es t ing,
etc."
Such noz zle load c alculations are tracked and ho ld a "c onfirmat ion req ui r ed" not at ion unt il nozzle loadings are reconciled.
This pa rt ic ula r sys t em had not been reconciled either thru the ve ndo r or by SWEC.
To reconcile the a finite element analysis of the nozzle loading s, SWEC is pe rfo rming
^
vessel and its associated supports.
The results of the analysis to date demonstrate a requirement for additional support primarily due to seismic reactions of the free, cantilevered, and on a relatively flexible nozzle on a thin shelled vessel.
A revised suppo rt configuration has be en established using heavy wall fittings that limits piping reactions within allowab le equipment nozzle loadings.
SWEC is now as ses sing the ef fect s of heavy wall fittings on this revised design fo r comparison with the standard approach of using nominal wall fitting for pipe stress modeling.
In keeping with the discussion held with the NRC (Region I and NRR) at the job site on July 27, 19 83, we plan to have fur the r details arvi a final disposition and assessment available October 28, 1983.
5.
CORRECTIVE ACTION TO REMEDY DEFICIENCIES The corrective act ion fo r the diesel generato r exh au s t system, if any, will be initiated af ter the engineering evaluation noted in Section 4 is c omple t e.
6.
ADDITIONAL REPORTS The subseque nt repo rt on the status of the diesel ge ne rato r exh au s t system will be issued by Duquesne Light Company by October 28, 1983.
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