ML20141N381
| ML20141N381 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 02/14/1986 |
| From: | Gridley R TENNESSEE VALLEY AUTHORITY |
| To: | Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| NUDOCS 8603060300 | |
| Download: ML20141N381 (2) | |
Text
- _ _ - -.
. _ ~ _ -.
-.~
C
1, February 14, 1986 r,
m BLRD-50-438/86-04
'F.
3 BLRD-50-439/86-03
^
'o i
N N
U.S. Nuclear Regulatory Conunission Region II Attention:
Dr. J. Nelson Grace Regional Administrator 101 Marietta Street, NW, Suite 2900 1
Atlanta, Georgia 30323 i
Dear Dr. Grace:
4 i
BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 - USE OF COMPUTER-ROUTED CABLE LENGTHS IN DESIGN CALCULATIONS - BLRD-50-438/86-04, BLRD-50-439/86 FINAL REPORT The subject deficiency was initially reported to NRC-01E Inspector Al Ignatonis on January 16, 1986 in accordance with 10 CFR 50.55(e) as SCR BLN EEB 8548. Enclosed is our final report.
j If there are any questions, please get in touch with R. H. Shell at FTS l
858-2688.
l Very truly yours, TENNESSEE VALLEY AUTHORITY
/
j R.
. Crid1 y Manager of icensing I
l Enclosure cc Mr. James Taylor, Director (Enclosure)
Office of Inspection and Enforcement sl U.3. Nuclear Regulatory Conunission j
Washington, D.C.
20555 l
Records Center (Enclosure)
Institute of Nuclear Power Operations j
1100 circle 75 Parkway, suite 1500 Atlanta, Georgia 30339
,g 1
0603060300 860214 DR ADOCK 05 1
/
(t An Equal Opportunity Employer yj;,;; y
T t
O ENCLOSURE BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 USE OF COMPUTER-ROUTED CABLE LENGTHS IN DESIGN CALCULATIONS BLRD-50-438/86-04 AND BLRD-50-439/86-03 SCR BLN EEB 8548 10 CFR 50.55(e)
FINAL REPORT Description of Deficiency Bellefonte Nuclear Project calculations may have a deficiency with the use of computer-generated electrical cable lengths--rather than actual installed lengths--in design calculations because, typically, actual installed lengths are longer. This creates a discrepancy in voltage drop calculations.
The root cause of this deficiency is a failure of designers to recognize that the computer-generated lengths and the actual lenrths are sufficiently different to modify the results; thus, it was not recognized that an unverified assumption was being made in the calcilations.
The problem also has been identified on other TVA nuclear plants as follows:
Sequoyah Nuclear Plant SCR SQN EEB 8602 Browns Ferry Nuclear Plant SCR BFN EEB 8601 Watts Bar Nuclear Plant PIR WDN EEB 8605 Safety Implications The use of computer-routed cable lengths in calculations could lead to the erroneous conclusion that safety components would operate satisfactorily under degraded voltage conditions; therefore, this condition could affect the safe operation of the plant.
Corrective Action Bellefonte Nuclear Plar.t will revise those affected calculations to use actual installed lengths or cut lengths that are greater to ensure that the voltage is adequate for component operation. Any circuits that are found to be inadequate will be corrected by appropriate measures, such as rerouting or i
resizing.
Any rework of deficient cables will be complete by six months before fuel load of the applicable unit.
1 l
l J
o
,s In order to prevent recurrence of this problem, BLUP-01, " Design projects Detailed Instructions for Design / Check of Cable Schedules," will be revised to require the use of either the cut cable length or actual installed cable length in voltage drop calculations. This procedure will be revised by June 30, 1986.
l l
l
.