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Holtec Center, 555 Lincoln Drive West, Mariton, NJ 08053
Telephone (856) 797-0900
HOLTEC Fax (856) 797-0909
INTERNATIONAL
BY FAX AND OVERNIGHT MAIL
March 6, 2003
U.S. Nuclear Regulatory Commission
ATTN: Document Control Desk
Washington, DC 20555-0001
Subject: 10 CFR 21 Notification for Aalborg Flow Meters
Dear Sir:
Pursuant to Holtec Quality Procedure HQP 15.1, "Reporting of Defects and
Noncompliances per
10CFR21," Holtec International hereby notifies the Commission of a potential
defect in flow
measuring instruments provided by a U.S. supplier to verification the correct
amount of helium is
backfilled into dry spent fuel storage canisters. These instruments were never
used on a Holtec
cask system containing spent nuclear fuel because the problem was discovered
during the
preparatory phase before fuel loading. A summary of the issue is provided below.
Name and Address of Individual Informing the Commission:
Mr. Brian Gutherman
Manager, Licensing and Technical Services
Holtec International
Holtec Center
555 Lincoln Drive West
Marlton, NJ 08053
Identification of the Basic Component Supplied Which Contains a Defect:
Aalborg flow meter Model GFM67 15
Identification of the Firm Suppiving the Basic Component Which Contains a Defect:
Aalborg Instruments and Controls
Page 2 of 4
Nature of the Defect and the Safetv Hazard Which Could Be Created by the Defect:
Four Aalborg model GFM671S mass flow rate meters were purchased for use at the
Trojan nuclear
plant to measure the amount of helium gas injected into a loaded Holtec dry
spent fuel Multi-
purpose Canister (MPC). One flow rate meter was to be used as the measurement
device on the
MPC helium flow and a second meter was to be used to cross check the calibration
of the first meter
following completion of the helium backfill. Two additional flow rate meters
were purchased as
spares. The flow rate meters were procured as commercial items from a distributor.
All of the flow
rate meters were calibrated at the original manufacturer (Aalborg) using nitrogen
test gas and
correction factors published by Aalb org to indicate helium flow rate. Three
of the flow rate meters
were subsequently sent to Holtec's approved calibration facility (Laboratory
Testing Inc. (LTI)).
LTI subcontracted the calibration work to its approved supplier (Edison). After
calibration, the
three flow rate meters were sent to Trojan and used during dry runs and demonstrations.
The fourth
flow rate meter was not calibrated or used.
During pre-loading activities, the helium volumes indicated by flow totalizers
were confirmed to be
consistently lower than the actual volumes depleted from the helium cylinders.
The flow totalizers
calculate total helium volume using input from the flow rate meters. It was
determined that
erroneous data was coming from the flow rate meters and that the flow totalizers
were operating
correctly. Numerous tests were run using all three calibrated flow rate meters
and they consistently
indicated low values. Although the flow rate meters were within calibration
tolerances when tested
with nitrogen and corrected per the manufacturers directions, when helium was
actually run through
the meters, the indicated flow rate was lower than the actual flow rate. The
three calibrated flow
rate meters were returned to Aalborg for evaluation where it was determined
by Aalborg that the
published correction factors for helium/nitrogen were incorrect for this model
flow meter.
As received at the Trojan site, the flow rate meters indicated values approximately
40% lower than
the actual flow rate of helium through the meter based on the depletion of the
helium bottles. Use of the mis-calibrated could cause approximately 67% more
helium to be injected into the MPC than
permitted by the Trojan ISFSI Technical Specifications. The addition of excess
helium beyond the
range specified in the Technical Specifications would have placed the MPC in
an unanalyzed
condition. The maximum initial helium fill pressure inside the MPC is used in
the evaluation of off-
normal and accident overpressure events. Too high an initial fill pressure could
result in the
computed pressure in the MPC after certain accidents to be higher than previously
analyzed. For normal operations, higher MPC backfill pressure (indicative of
higher helium backfill mass) would
provide better heat transfer and would, therefore, provide better protection
of the fuel cladding
during storage of the ISFSI.
At the time the discrepant condition was identified, none of the flow meters
had been used on an
MPC loaded with spent fuel and they were subsequently rernoved from service
until they could be
correctly calibrated.
The Date on Which the Information of Such Defect was Obtained:
January 3, 2003
The Number and Location(s) of the Basic Component Which Contains the Defect
Four flow rate meters were procured and delivered to the Trojan nuclear power
plant. Three were
calibrated by a QA-qualified calibration facility and destined for use, but
were not used in actual
fuel loading activities due to the discovery of the mis-calibration during dry
run activities. The
fourth flow rate meter has been removed from the site.
Corrective Action Which Has Been Is Being, or Will Be Taken
The three affected flow rate meters were removed from service and sent back
to Aalborg for re-
calibration. Holtec witnessed the re-calibration and the flow meters were subsequently
placed
into service at Trojan plant. Aalborg is developing new helium correction factors.
In the interim,
they have committed to using helium to calibrate all flow meters destined for
use in measuring
helium.
Any Advice Related to the Defect about the Basic Component That Has Been, Is
Being, or Will
Be Given to Purchasers or Licensees:
Trojan plant was the first plant where flow rate meters and flow totalizers
were to be used to
confirm adequate helium backfill in Holtec MPCs loaded with spent fuel. Therefore,
no other
Holtec client is affected for past loading operations. For future MPC loading
operations, Holtec's
users, as well as other purchasers and licensees are being notified via this
report that Aalborg
flow meters procured for use in important-to-safety activities may not be calibrated
correctly and that certain catalogue correction factors have been determined
to be incorrect. The calibration of
Aalborg flow meters should be confirmed prior to use in important-to-safety
activities.
If you have any questions or require additional information, please contact
the undersigned at
(856) 797-0900, extension 668.
Sincerely,
Brian Gutherman, P.E.
Manager, Licensing and Technical Senvices
emcc: Mr. Mark Soler, Holtec
Mr. Joel Westvold, PGE
Mr. David Larkin, HUG Chairman
Mr. Chris Regan, USNRC
Document I.D.: 5014481