ML19305C111
| ML19305C111 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 02/04/1980 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Pilant J NEBRASKA PUBLIC POWER DISTRICT |
| References | |
| NUDOCS 8003260008 | |
| Download: ML19305C111 (1) | |
Text
bec to DAC:ADM:
CENTRAL FILES w
UNITED STATES PDR:HQ
_f 4c NUCLEAR REGULATORY COMMISSION LPOR asanoN IV g.,-TT("
f g'(M, 7 ;:
611 RY AN Pt.AZA oRIVE, SulTE 1000 e
e gg{g
)
ARuNaToN, TEXAS 78012
%,.... /
February 4, 1980 States Docket No. 50-298 Nebraska Public Power District Al"IN:
J. M. P11 ant, Director Licensing & Quality Assuranca Post Offica Box 499 Columbus, Nebraska 68601 Gentleman:
This IE Information Notica is providad as an early notification of a possibly significant mattar.
It is expected that recipients will review the information for possible applicability to their facilities.
No specific action or response is raguasted at this etne.
If further NRC evaluations so indicata, an II Circular or Bulletin will be issued to recommand or request specific licensea actions.
If you hava questions regarding this matter, please contact the Director of the appropriate NRC Regional Offica.
Sincaraly,
&g y
J Karl V. Seyfri Director
Enclosures:
1.
IE Information Notica No. 80-04 2.
List of Racantly Issued IE Information Notices L. C. Lassor, Superintendent ec:
}
Cooper Nuclear Station i
Post Offica Box 98 Brownv111a, Nebraska 68321 l
l l
l l
8 0 032 60 O$h
cm y,
ng La
. c0 29 su UNITED STATES SSINS No.:
6870 NUCLEAR REGULATORY COMMISSION Accession No.:
OFFICE OF INSPECTION AND ENFORCEMENT 7912190655 WASHINGTON, D.C.
20555 IE Information Notice No. 80-04 Date:
February 4, 1980 Page 1 of 2 BWR FUEL EXPOSURE IN EXCESS OF LIMITS On November 1, 1979, and December 17, 1979, respectively, the licensees of the Quad Cities Unit No. I and Monticello Nuclear Power Plants informed the Nuclear Regulatory Commission that the actual peak average planar exposure of some -fuel assemblies in the core was beyond the maximum average planar exposure value of the Maximum Average Planar Linear Heat Generation Rate (MAPLHGR) Limits specified in the plant Technical Specifications.
In the case of Quad Cities, the licensee was aware that some luel assemblies would approach and exceed the exposures for which MAPLHGR limits had been analyzed.
In the interim, the station process computer was used to calculate higher exposure MAPLHGR limits via an extrapolation routine, while awaiting determination of the additional high exposure MAPLHGR _imits using standard licensing analysis methods. When the actual limits were made available for comparison with the extrapolated values, it was determined that the process computer had extrapolated values non-conservatively. Although the new MAPLHGR limits extensions were immediately entered into the computer, the new limits had not yet been submitted for review and approval by the NRC.
With regard to Monticello, the licensee became aware that the 30,000 MWD /T maximum exposure specified in the plant Technical Specifications were being exceeded after several months of operation had elapsed. Although the high burnup fuel assemblies had at no time exceeded the MAPLHGR value corresponding to 30,000 MWD /T, MAPLHGR limits calculated by standard licensing analysis methods showed that lower MAPLHGR values should have been utilized at the higher exposures. Again although the new MAPLHGR limits were promptly substituted, the new limits were not at the time formally approved by the NRC.
In-both cases, it was subsequently determined by the licensees that the actual operating MAPLHGR values had at no time exceeded the revised MAPLHGR limits at the higher exposures.
The licensees subseq ently requested amendments to their Technical Specifications, adding MAPIdGR limits for average planar exposures values beyond the actual peak average planar exposure projected for the present cycles.
These changes have been reviewed and approved by the staff.
Additionally, fuel rod thermal-mechanical design and safety analyses for the subject fuel are dependent on local-(peak pellet) exposure conditions. The peak pellet exposure basis for those analyses is 40,000 MWD /T.
Since the peak pellet exposure exceeds the fuel assembly maximum average planar exposure as fuel assembly average planar exposure increases, the concern is raised that the l
l
Information Notice No. 80-04 Date:
February 4, 1980 Page 2 of 2 40,000 MWD /T fuel thermal-mechanical analysis basis exposure could also be approached or exceeded.
Investigations conducted by the licensees showed that the peak pellet exposure had not nor would not exceed the fuel thermal-mechanical design maximum basis during the current operating cycles.
The potential for occurrence of the above events can be decreased by (a) surveillance procedures which require periodic comparison of actual peak average planar exposure and peak pellet exposure values to approved exposure limits, and (b) use of the computer to provide an alarm or flag as an aid to indicate when approved exposure limits are being approached.
This IE Information Notice is provided to inform licensees of a significant safety matter.
It is expected that recipients will review the information for possible applicability to their facilities. No specific action or response is requested at this time.
If you have any questions regarding this matter, please contact the Director of the appropriate NRC Regional Office.
l
o.
IE Information Notice No. 80-04 February 4,1980 LISTING OF RECENTLY ISSUED IE INFORMATION NOCCES Information Subject Date Issued To Notice No.
Issued 79-33 Improper Closure of 12/21/79 All power reactor Primary Containment facilities holding Access Hatches Operating Licenses (0L) and Construction Permits (cps) 79 Inadequate Design of 12/27/79 All holders of of Safety-Related Heat -
power reactor Exchangers Operating Licenses (OLs) and Con-struction Permits (cps) 79-35 Control of Maintenance 12/31/79 All power reactor facilities and Essential Equipment with an Operating Licenses (OLs) and Construction Permits (cps) 79-36 Computer Code Defect 12/31/79 All holders of power reactor 4
Stress Analysis of Piping Operating Licenses (OLs)
Elbow and Construction Permits (cps) 79-37 Cracking in Low Pressure 12/28/73 All holders of power reactor Turbine Discs Operating Licenses (OLs) and Construction Permits (cps) 80-01 Fuel Handling Events 1/4/80 All holders of power reactor Operating Licenses (OLs) and Construction Permits (cps) 80-02 8X8R Water Rod Lower 1/ 25/80 All BWR Facilities End Plug Wear holder of powtr reactor t
Operating Licenses (OLs) or Constructi# Permits (cps) 80-03 Main Turbine Electro-1/31/80 All holders of power Hydraulic Control System reactor Operating Licenses (OLs) and Construction Permits (cps)
Enclosure
-