ML20009D522

Deficiency Rept Re Design Deficiency in Hydrogen Recombiner Sys,Initially Reported 810616.Discharge Lines Will Be Rerouted & Connected to Penetrations M-104 & M-106.Design Documents Have Been Revised & Issued for Const

ML20009D522
Person / Time
Site:	LaSalle
Issue date:	07/16/1981
From:	Swartz E COMMONWEALTH EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
10CFR-050.55E, 10CFR-50.55E, 2305N, NUDOCS 8107240142
Download: ML20009D522 (2)

Text

/"X Commonwealth Edison [//Jd 8718

/ ) On3 First Nttional Plata. Chictgo, Illinois

. $ 7 h Address Reply to: Post Office Box 767

/ Chicago, Illinois 60690 July 16, 1981

. -601Wl,g fF s p Mr. James G. Keppler, Director /' 8 d) p*\

Directorate of Inspection and Enforcement - Region III /Z Al 2 3 798t n :l U.S. Nuclear Regulatory Commission u.ai ammaa mmwo , i 799 Roosevelt Road -

• • • "" * ,"/

Glen Ellyn, IL 60137 M7 6

Subject:

LaSalle County Station Units 1 Design Deficiency in the Hydrogen and k i h ,

Recombiner System NRC Docket Nos. 373/374

Dear Mr. Keppler:

On June 16, 1981, Commonwealth Edison Company LSCS Project Engineering notified Mr. Frank Reimann of your office that the Hydrogen Recombiner System at LaSalle County Station appeared to have a desigr deficiency reportable pursuant to 10CFR50.55(e). This letter fulfills the thirty (30) day reporting requirements of 50.55(e) regarding this item.

DESCRIPTION OF DEFICIENCY During preoperational testing at LaSalle County Station, a test engineer discovered that the water level in the suppression pool was above the hydrogen recombiner return line. Since this is contrary to the system design, this problem was reviewed to determine if the suppression pool level could rise above the recombiner discharge line after an accident or transient. The water level was calculated to potentially increase to elevation 706'-11".

The recombiner discharge lines are currently attached to primary containment penetrations M-95 and M-102 which are located at elevation 701'-0". The normal suppression pool water level is 699'-11".

T s

ANALYSIS OF SAFETY IMPLICATIONS / p The design flow rate for the hydrogen recombiner is 150 scfm, and the minimum flow rate needed to prevent the formation of a combustible gas mixture in the containment is 127.5 scfm. If the suppression pool level is allowed to rise above the discharge line, the discharge pressure head will increase thus decreasing the flow rate. According to the blower performance curve supplied by the vendor, an increase in the discharge pressure head of only 9 inches of H2 O will drop the flow rate about 25 scfm. Therefore, at the suppression pool water levels postulates to occur after an incident, the hydrogen recombiners would not be able to perform their intended safety related function.

8107240142 810716 PDR ADOCK 05000373 00r 22 0 1981 S PDR

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J. G. Keppler July 16, 1981 CORRECTIVE-ACTION The discharge lines will be rerouted and connected to penetrations M-104 and M-106 which are located at elevaticr 725'6" and;;re above-the maximum suppression pool water level postulated to occurfaiter a LOCA or transient. The applicable design documents have been revised-and issued for construction, which is currently in

progress. Construction will be completed by fuel load.

. .Please address any further questions that you may have concerning this matter to this office.

Very truly yours,

./ -

ysW'"

E. Douglas Swartz Nuclear Licensing Administrator

.cc: Director of Inspection and Enforcement im 2305N-i