ML20094A555
| ML20094A555 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 10/25/1984 |
| From: | Kober R ROCHESTER GAS & ELECTRIC CORP. |
| To: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| NUDOCS 8411060464 | |
| Download: ML20094A555 (2) | |
Text
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-4 ROCHESTER GAS AND ELECTRIC CORPORATION e 89 EAST AVENUE, ROCHESTER, N.Y.14645'b001 %
ROGER W. KOtsER wct mewar t e t t h o* E nzcTan: a strau secouctiore mara coor m 546-2700 October 25, 1984 Dr. Thomas E. Murley, Regional Administrator U.S.
Nuclear Regulatory Commission Office of Inspection and Enforcement Region I 631 Park Avenue King of Prussia, Pennsylvania 19406
Subject:
Error found in Calorimetric Calculations at R. E.
Ginna Docket No. 50-244
Dear Dr. Murley:
On September 20, 1984, a review was being performed of a 1977 design analysis dealing with the accuracy of the secondary system calorimetric calibration.
This review was part of a performance audit being conducted by the New York State Public Service Commission.
As a result of this review it was discovered that the number used in the calorimetric equation for non-reactor heat inputs was in error in the non-conservative directian by approximately two-tenths of one percent (.2%).
The non-reactor heat inputs are derived from the algebraic sum of various components and support systems that either add heat to the reactor coolant system or remove heat from it.
Examples of these components include the reactor coolant pumps, charging, letdown, seal injection,; seal return, reactor vessel support cooling, pressurizer heaters and ambient losses.
The 1977 design analysis established this number as 17.574 x 106 BTU /hr.
A further investigation revealed that a 1969 initial 6
plant heat rate test established this number at 22.241 x 10 BTU /hr.
The 1969 initial plant heat rate number was converted to a percent of licensed reactor power and subtracted for the calculated calorimetric power.
The percent of licensed power was based on the then licensed power lerel of 1300 thermal megawatts.
This number computed to be.50127 percent and for conservative measures
.5 percent was used in the calculation.
On March 1, 1972, licensed thermal power rating was increased to the present day 1520 thermal megawatts.
Since the change in thermal rating does not significantly affect the non-reactor heat inputs, a reduction in the percent of thermal power inputted from non-reactor heat inputs should have resulted.
Cont.rary to this, no reduction occurred and the calorimetric calculation has been in error ever since.
8411060464 841025 Q
PDR ADOCK 05000244 R
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ROCHESTER GAS AND ELECTRIC CORP.
SHEET NO.
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DATE October 25, 1984
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Dr. Thomas E.LMurley On September 21, 1984, the Plant Superintendent requested that the Technical-Manager and the corporate nuclear-engineer review these calculations'again before any action would be taken.
This re-review yielde'd the.same result; i.e.
that the calorimetric was.in error by approximately.2% in the non-conservative direction.
The results of the re-verification did not change.
-It was recommended that the power level be immediately reduced by.approximately.2%
and that the calorimetric procedure be-changed to. reflect a conservative number for the non-reactor heat innut.
This new conservative 4
'r. umber was gomputed from the 1977 design analysis assumption of 17.574 x 10 BTU /hr. with an additional 10% uncertainty factored in.
The net result was that.3% of 1520 megawatts should.lua used as a conservative-estim< ate of the non-reactor heat inputs.
This, event was then reviewed relative to the reporting.
criteria as set forth in 10CFR50.72 and 10CFR50.73.
It was determined by the Plant Operations Review Committee (PORC) with concurrence received from your Resident Inspector that this event was not reportable under either 10CFR50.72 or 10CFR50.73 criteria.
However, the PORC decided that because of the nature of this event a formal written report should be forwarded to your office.
1 Subsequent to this report a detailed analysis of the non-reactor heat inputs will be performed and adjustments made as necessary to the calorimetric procedure.
Very truly yours, FL Roger W.
Kober P
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