ML20084F734
| ML20084F734 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 04/30/1984 |
| From: | Dixon O SOUTH CAROLINA ELECTRIC & GAS CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-2.F.2, TASK-TM GL-82-28, NUDOCS 8405040298 | |
| Download: ML20084F734 (4) | |
Text
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SOUTH CAROLINA ELECTRIC & GAS COMPANY POST OFFIC. 764 COLuualA. SOUTH CAROUNA 29218 O. W OlXON, JR, April 30, 1984 vice p...io ~r Nuctean OrspatioNS Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Comission Washington, DC 20555
Subject:
Virgil C. Sumer Nuclear Station Docket No. 50/395 Operating License No. NPF-12 Inadequate Core Cooling, NURE-0737, II.F.2
Dear Mr. Denton:
In Mr. T. M. Novak's "05000395/LER-1983-141-03, /03L-0:on 831215,while in Mode 2,snubbers MSH-324 & MSH-325 Declared Inoperable.Caused by Transient in 32-inch [[system" contains a listed "[" character as part of the property label and has therefore been classified as invalid. Which Induced 850 Lb Load in 4-inch Line. Snubbers Replaced|letter dated January 12, 1984]], on Generic Letter 82-28 Response, NURm -0737, Item II.F.2, the NRC requested additional information on the Reactor Coolant Inventory Tracking System, Core Exit Thernoccuple System and Subcooling Margin Monitor System utilized at the Virgil C. Sumer Nuclear Station. Responses to itens 1 and 2 of enclosure 2 of the referenced letter were provided in our letter to you dated February 17, 1984; the additional information requested in enclosure 2, item 3 and in enclosure 3 is provided below., Item 3 The staff requested that South Carolina Electric and Gas Cmpany (SCEEG) justify that the caution alarm setpoints on the subcooling margin monitor will provide sufficient margin for operator action.
Response
The subcooling margin nonitor does not provide an alarm which requires the operator to take imediate action to prevent core damage. The subcooling caution alarm setpoints (15* for T/C input, 25' for RID input) are selected based on normal operating parameters and not operator time response. During normal operations, the margin of subcooling is approximately 20*F based on T/C inputs and 29' F based on RID inputs. The caution alarm nust be set below the normal operating tenperatures to preclude spurious alarms. During normal operation, protection against departure from nucleate boiling is provided by the low pressurizer pressure and overtenperature AT reactor trips, not by operator action. During accident conditions, core protection is provided by inplementation of appropriate emergency operating procedures. These procedures direct operator response to prevent the core from reaching a point of inadequate cooling. The inmediate action for a caution alarm on the sub e ling monitor is to verify that-inadequate core cooling conditions exist by observing indimtions on the l
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Mr. Harold R. Denton Inadequate Core (boling NURB3-0737, II.F.2 April 30, 1984 Page #2 Core Subcooling Manitor Panel and RCS tenperature and pressure. If inadequate core cooling is confirmed, then the operator is directed to take further supplemental actions to correct the condition., Inplanentation Ietter Report Content, Items 1-4 (1) Provide notification that the systen installation, functional testing, and calibration is couplete and test results are available for 4
inspection.
Response
te Reactor Vessel Ievel Instrumentation Systen (RVLIS) was installed prior to Novenber 15,.1981. %e initial calibration was conpleted and is docunented in phase one startup test procedures. We functional testing was conpleted satisfactorily and is docunented in another phase one startup test procedure. his docunentation is available for inspection at the Virgil C. Summer Nuclear Station.
(2) Provide a sunnary of licensee conclusions based on test results, e.g:
(a) the systen performs in accordance with design expectations and with design error tolerances, or (b) description of deviations from design performance specifications and basis for concluding that the deviations are acceptable.
Response
~
During testing, the RVLIS has performed in accordance'with design expectations and within design error tolerances. %erefore, no. changes were required to be made to the performance ~ specification.
(3) Provide a description of any deviations of the as-built system '
from previous design descriptions with any appropriate explanation.
Response
here are no major deviations in the RVLIS as-built systen from that:
described to the NRC in the letter from T. C. Nichols, Jr. to H. 'R.
Denton dated December 30, 1980.- However, there are scxne minor changes in the ranges of the level. indicators from those listed in FSAR
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Mr. Harold R. Denton Inadequate Core Cooling NIREG-0737, II.F.2 April 30, 1984 Page #3
,r Table 7.5.1.
%is table lists the Reactor Vessel Ievel indicators with ranges of 0-100%. %e ranges listed in this table were based on l
preliminary design information and the indicators as actually installed have labels and ranges as follows:
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Upper Plenura Ievel 60-110%
NR Ievel 0-110%
WR Ievel 0-110%
4 Based on additional experience with the' system, Westinghouse has recomended that we modify our systs to include refinments in indicator titles and ranges as follows:
~
Upper Range.
64-120%
Full Range
- 0-120%
j Dynamic Head **
0-120%
No RCP running i
One or more RCP running Please note that what is now titled Upper Plentat Ievel will be titled '
Upper Range; what is now titled Narrow Range (NR) will be titled Full'.
Range; and what is now titled Wide Range (WR) will.be titled Dynamic l
Head.
% is modification and the corresponding reaalibration of the associated j
transmitters are scheduled for inplementation during the first refueling outage currently planned for October,1984.- t e FSAR and the appropriate procedures will be revised at.that time to reflect the I
revised titles and ranges.
I he extension of the Dynamic Head indicator to 120%-is based on A
1 analytical results that show full power readings of.approximately 108-112%.- At zero power this indicator will read approximately 100%.
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%e Upper Range and Full Range indicators are. extended to match the Dynamic Head indicator for human factors reasons.-
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(4)- Confirm that the EDPs used for operator training conform to the.
technical content of NRC approved BOP guidelines-(generic or.. plant, specific).
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Response
Y he current:Bnergency Operating Procedures (EOPs)'are based on the'
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- Weatinghouse Energency Operating Instructions which were current-in
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1981/1982. %ese BOPS were reviewed and accepted bythe IWC in the
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4 Mr. Harold R. Denton Inadequate Core Cooling NOREG-0737, II.F.2 April 30, 1984 Page #4 following documents:
Supplanent 4 to the Virgil C. Sumer Nuclear Station Safety a.
Evaluation Report.
b.
Region II Inspection Report 50-395/82-28.
c.
NRC Menorandum from William G. Kennedy to lingh 'Ihonpson, Jr.,
" Reevaluation of the Virgil C. Sumer anergency Operating Procedures," dated 02/01/82.
The EDPs are currently being revised in accordance with the Westinghouse Owners Group Emergency Response Guidelines, Revision 1.
Operator training and inplementation of the revised EDPs will be cmpleted prior to startup after the first refueling.
Should there be any questions, please notify us at your convenience.
Very truly yours, q s/
)
O. W. D Jr.
JG:OWD:tdit/gj cc:
V. C. Sunmer T. C. Nichols, Jr./O. W. Dixon, Jr.
E. H. Crews, Jr.
E. C. Roberts W. A. Williams, Jr.
D. A. Nauman 4
J. P. O'Reilly Group Managers O. S. Bradham C. A. Price C. L. Ligon (NSRC)
K. E. Nodland R. A. Stough 1
C. W. Hehl J. B. Knotts, Jr.
NPCF File l
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