ML20126E235

Application for Amend to License NPF-12,revising TS Bases 3/4.5.4 & 3/4.6.2.2 to Lower Value of Ph Range of Solution Circulated Through Sump Following Design Basis Loca,Based on More Rigorous Calculations to Update RB Spray Sys

ML20126E235
Person / Time
Site:	Summer
Issue date:	12/22/1992
From:	Skolds J SOUTH CAROLINA ELECTRIC & GAS CO.
To:	George Wunder NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20126E238	List: ML20126E235 ML20126E243
References
NUDOCS 9212290064
Download: ML20126E235 (2)

Text

_ _ - _ _ - _ _ _ _

5 South Carolins E12ctric & G:s Company John L. Skold) -

P.O Box 88 Vee President Junansvme. SC 29005 Nuclear operahons l ,

(B03) 345 4040 SCE&G December 22, 1992 Document Control Desk U. S. Nuclear Regulatory Commission Washington, DC 20555 Attention: Mr. G. F. Wunder

Subject:

VIRGIL C. SUMMER NUCLEAR STATION DOCKET NO. 50/395 OPERATING LICENSE NO. HPF-12 REVISION TO TECHNICAL SPECIFICATION BASES 3/4.5.4 AND 3/4.6.2.2 (TSP 900007-0)

The attached Technical Specification Bases change revises the lower value of the c4 range of the solution recirculated through the sump following a design be- loss of coolant accident (LOCA). The revision is a result of more rigorous calculations performea to update the Reactor Building (RB) Spray System / Chemical Drawdown pH Analysis. A 10CFR50.59 evaluation has been performed to demonstrate that the revision to the sump lower pH value from 7.8 to 7.5 does not pose an unreviewed safety question and is summarized below.

Bases Sections 3/4.5.4, " Refueling Water Storage Tank (RWST)," and 3/4.6.2.2,

" Spray Additive System (SAS)," provide the bases for the limits on required volume and concentrations of boron and sodiuia hydroxide (NaOH). In addition to ensuring that the core is maintained subcritical and that sufficient NaOH is added to the RB spray following a LOCA, the subject ?'mits ensure that the pH of the solution recirculated through containment is maintained within a band which minimizes the evolution of iodine and the effects of chloride and caustic stress corrosion.

South Carolina Electeic & Gas Company (SCE&G) has determined that the revised lower pH value supports the bases for the pH range delineated in Bases 3/4.5.4 and 3/4.6.2.2. Specifically, the results of the SCE&G evaluation show that the revised minimum value:

(a) Supports the spray cemoval coefficient assumed in the Final Safety Analysis Report (FSAR) dose analysis, (b) Supports the elemental iodine decontamination factor assumed in the FSAR dose analysis, (c) Minimizes the effect of chloride stress corrosion cracking of stainless steel, (d) Minimizes the effect of caustic stress corrosion, and -

(e) Maintains the rate of hydrogen generation (due to the corrosion of zinc and aluminum) below that specified in the FSAR.

2800SO 4 9212290064 921222 pp/ I PDR ADOCK 05000395 PDR p f

. , ~ . . . -

l '

Document Control Desk .

~ TSP 900007-0 Page 2 4

SCE&G requests that NRC provide revised. Technical Specifications Bases pages.

Requests of this nature do not require a No Significant Hazards Evaluation because-the revision is to the Bases, not the Technical Specifications.

Should you have any questions, please call Ms. April R. Rice at (803)'345-4232 at your convenience. ,

very trul yours,

~

' [4 , . . la

/JohnLl.Skolds ARR:JLS:nkk Attachments c: 0. W. Dixon, Jr. (w/o attachments)

R. R. Mahan (w/o attachments)

R. J. White S. D. Ebneter General Managers NRC Resident Inspector J. B. Knotts, Jr.

H. G. Shealy L. R. Cartin NSRC RTS (TSP 900007)

File (813.20) 1 NUCLEAR EXCELLENCE - A SUMMER' TRADITION!

. . ,