ML20063H309
| ML20063H309 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 02/09/1994 |
| From: | Denton R BALTIMORE GAS & ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9402170285 | |
| Download: ML20063H309 (3) | |
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' ELECTRIC '
GAS 'AND :
.j 1650 CALVERT CUFFS PARKWAY 4 LUSBY, MARYLAND' 20657N702.:
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ROBERT E. DENTON l
' Vict PRESCENT.
February 9,1994 s
[7 NUCLEAR ENCROY
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U. S. Nuclear Regulatory Commissioni Washington,DC 20555; ~
ATTENTION:
. Document Control Desk 1 s
SUBJECT:
Calvert Cliffs Nuclear' Pawer'Planti.......
's Unit Nos.1 & 2; Docket Nos; 50-317 & 50-3185 1
10 CFR 50.9 Notification Concerning Erroneous Inf6rmatiori Suhplied in'a License Amendraent Reauest i
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REFERENCES:
(a) letter fromiE. Denton (BGAE)1to Document Control Center; #
!(NRC), dated _. April 1,:1993, License: Amendment Request;;Onsite Power Distribution Systems,'A.C. Distribution - Operating :
'(b)
- Ietter from D. G. MEDonald (NRC) to RlE. Dentbn (BG&EI, dated) ~
October 29,1993, Issuance of Amendments for Calvert Cliffs Nuclear?
Power Plant, Unit No.1 and Unit No. 2;
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On February 3,1994 we discovered an'errolin a' Licdnse Amandment R'equest.iThis' error was notJ identified until after the Nuclear Regulatory Commissiori (NRC) issued a corresponding Ucense; l
Amendment and Safety Evaluation' Report (SER).f. Since this'information;wasLused by the NRC; l
during the technical review process in approWng the License Amendment, we have chosen to report l
this information under the requirements of 10 CFR 50.9(b);iWe verbally notified our NRC. Project 1
. Manager and Resident Inspectors office of the error.? Feedback from.our Regiona_1 Office indicated ;
L that a formal verbal notificatio' to the Regional Administrator was not warranted under 10 CFR 50.9 n
7 and submission of Attachment (1) was requested.
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Should you have any further questions regarding this matter, we will be pleased to discuss them withT l
you.
T Very truly yours, 1
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Document Control Desk
.. February 9,1994 Page 2 cc:
D. A. Bruac, Esquire l
J. E. Silber g, Esquire R. A. Capn, NRC D. G. Mc Donald, Jr., NRC T. T. Martin, NRC P. R. Wilson, NRC R. I. McLean, DNR J. H. Walter, PSC l
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l 4ITAClIMENT 0) 10 CFR 50.9 NOTIFICATION CONCERNING ERRONEOUS INFORMATION SUPPLIED IN A LICENSE AMENDMENT REOUEST We have discovered that an erroneous statement exists in a License Amendment Request and that error was reflected in the corresponding License Amendment and Safety Evaluation Report (SER) issued by the Nuclear Regulabry Commission (NRC). These documents indicate that our inverter backup bus is fed from a Class 1E transformer. In fact, the inverter backup bus receives power from -
a Class 1E source, but the transform:r itself is not a Class 1E component nor does.it supply Class 1E '
power to other components.
l In a License Amendment Request dated April 1,1993, Baltimore Gas and Electric Company requested a change to Technical SpecificWon 3.8.2.1, "Onsite Power Distribution Systems, A.C.
Distribution - Operating." The License Amendment. Request proposed extending the allowed l
outage time during Modes 1,2,3, and 4 with one 120 VAC vital bus powered by an inverter backup bus from 8 to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The request states, "The inverter backup bus is fed from a Class 1E 480/120 l
VAC regulated transformer (diesel backed). Therefore, the inverter backup bus is an interruptible l
source that is de-energized in a loss of offsite power (LOOP) and re-energized when the emergency diesel generator is connected to the 4 kv bus. Because the design of the 120 volt vital AC system is to i
provide continuous power to instrument and control circuits, the interruptible inverter backup bus is considered a backup power source, not an emergency power source, to the 120 Volt Vital'AC system." The submittal goes on to state that, "By using the backup bus, the RPS and ESFAS channel powered by the vital bus is able to perform its function for all analyzed design basis accidents except those involving a concurrent LOOP."
The requested change was approved by the NRC Staff on October 29,1993. The associated NRC -
SER states, "Although the inverter backup bus is fed from a Class 1E regulated transformer that, in turn, is backed by an emergency diesel generator, it is not capable of providing uninterruptible power to the vital busses during design basis events such as a loss of off-site power. Therefore it is not l
considered an emergency source of power. Currently when the backup bus is used, the vital bus it is powering is declared inoperable and an 8-hour action statement is entered."
A Design Engineer reviewing the SER noted the erroneous statement and notified Licensing of the discrepancy. Licensing reviewed the discrepancy and determined the erroneous information could have been relied on by the.NRC in reviewing the proposed change. _Upon reaching this conclusion Licensing contacted the NRC Project Manager and prepared an Issue Report to ensure the issue is addressed by our corrective action process.
We understand the need and requirement that allinformation provided to the NRC be accurate. We intend to provide a full and accurate description of the inverter backup bus and any additional information needed to permit a review of the Staff's conclusions in this matter. In the interim, we have administratively prohibited the use of the 24-hour action requirement until we receive the '
i results of this review.
We have utilized the 24-hour action statement only once since its approval. We were in the action statement for a 24-hour period between January 24 and 25,1994. The plant was in Mode 3 for the -
full 24-hour period. The maximum allowed outage time on the backup bus will be limited to the pre-amendment limit of eight hours.
We have initiated actions to address the generic implications of this event. A root cause analysis it underway to identify why the inaccurate information was not detected during our review and approval of the License Amendment Request. We willinform you of the results of this investigation and the corrective and preventative measures we intend to take.
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