05000317/LER-1997-001, :on 970110,spent Fuel Moved W/Ventilation Sys Inoperable & Missed Surveillance Occurred.Cause Analysis Being Performed to Determined Casual Factors & Generic Implications for Event.Surveillance Performed

:on 970110,spent Fuel Moved W/Ventilation Sys Inoperable & Missed Surveillance Occurred.Cause Analysis Being Performed to Determined Casual Factors & Generic Implications for Event.Surveillance Performed

ML20134J938
Person / Time
Site:	Calvert Cliffs
Issue date:	02/10/1997
From:	Katz P, Muth D BALTIMORE GAS & ELECTRIC CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-97-001, LER-97-1, NUDOCS 9702130029
Download: ML20134J938 (7)

LER-1997-001, on 970110,spent Fuel Moved W/Ventilation Sys Inoperable & Missed Surveillance Occurred.Cause Analysis Being Performed to Determined Casual Factors & Generic Implications for Event.Surveillance Performed

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(1) 10 CFR 50.73(a)(2) 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition
3171997001R00 - NRC Website

text

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4 PETE:l: E. K.t'r::

Baltimom Gas and Electric Company Plant General Manager Calvert Cliffs Nuclear Power Plant Calvert Cliffs Nuclear Power Plant 1650 Calvert Cliffs Parkway Lusby, Maryland 20657 410 495-4101 February 10,1997 U.S. Nuclear Regulatory Commission Washington, DC 20555 ATTENTION:

Document Control Desk -

SUBJECT:

Calvert Cliffs Nuclear Power Plant Unit Nos. I and 2; Docket Nos. 50-317 and 50-318; License Nos. DPR 53 and DPR 69 Licensee Event Report 97-001 Soent Fuel Moved with Ventilation System Inoperable and Missed Surveillances The attached report is being sent to you as required under 10 CFR 50.73 guidelines. Should you have questions regarding this report, we will be pleased to discuss them with you.

Very truly yours,

\\

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oocueT Len Nummenies PAos (s) veAn l secuewTiAL meviesow wummen numeen Calvert Cliffs, Unit 1 05000 317 97

- 001 00 03 OF 06 Ttxi y oraw speco a,enwea. use., :.;

copnes of NRC Fome 306N 07) \\ l to the air still escaping under the door. At 1715 that evening, it was determined that this condition was outside the design basis of the plant. It was therefore reported to the Nuclear Regulatory Commission via the Emergency Notification System. l On Wednesday, January 15, 1997, the System Manager tested various vent paths in the Auxiliary Building and found that during non-outage conditions, the SFP area would maintain a negative pressure versus the Auxiliary Building in any configuration with two air supply fans operating, and could do so, depending on the configuration, with one supply fan operating. Appropriate procedures will be revised and personnel trained prior to fuel movement to ensure that two supply fans are operating or that the SFP area is maintained at a negative pressure whenever fuel is being handled. On Wedr.esday, January 22, 1997 at about 1105 hours0.0128 days <br />0.307 hours <br />0.00183 weeks <br />4.204525e-4 months <br />, Surveillance Test Coordination personnel were reviewing the records for STP-542, which, at 18 month intervals, verifies the ability of the SFP ventilation system to maintain negative pressure relative to the outside atmosphere and the Auxiliary Building, in accordance with Technical Specification Surveillance Requirement 4.9.12.d.2. They found that the full STP had not been run since September of 1994 and was due in March 1996. The test had been partially run on July 18, 1995 following replacement of the HEPA banks. The partial test verified exhaust fan operability, HEPA bank operability and air distribution. It did not verify negative pressure versus the outside or the Auxiliary Building. The Functional Surveillance Test Coordinator reviewed the test and, failing to recognize that the section verifying negative pressure had not been run, crroneously concluded that the test was complete. He reset the 18 month clock following the partial test. Failure to perform the STP within the required time limit constituted a condition prohibited by Technical Specifications. Both Units were in MODE 1 at 100 percent power and normal operating temperature and pressure at the time of discovery. II.

CAUSE OF EVENT

This event resulted from insufficient consideration of and inadequate barriers erected to ensure that the assumptions of the UFSAR fuel handling accident safety analysis were met.

Section 14.18.3.2.d of the UFSAR, " Fuel Handling Incident in the Spent Fuel Pool Area," states that, "All of the activity released to the air above the spent fuel pool is assumed to be discharged to the outside atmosphere through charcoal filters." Air leaking from the SFP area to the Auxiliary Building in the event of a fuel handling accident would not pass through charcoal filters.

Technical Specification Surveillance Requirement 4.3.12.d.2 requires verification that *each exhaust fan maintains I

the spent fuel pool area at a measurable negative pressure relative to the 1

NRC FORM $66A U.S. NUCLEAR RE4ULATORY COMMIS810N (4-95)

LICENSEE EVENT REPORT (LER) 4 TEXT CONTINUATION FAQUTY NAME W OOCKET LER NUMSER 18)

PAGE (3)

YEAR SEQUENTIAL REVISION NUNGER NUNDER I

Calvert Cliffs, Unit 1 05000 317 97

- 001 -

00 04 OF 06 ft.XT pt more space ss registed, uso soumones copes of NRC Form 3664 (I T) 1 i

outside atmosphere during system operation." Surveillance Test Procedure STP-M-542 tests for negative pressure versus outside air and surrounding areas, including the Auxiliary Building. However, this procedure does not i

account for possible bypass flow as a result of ventilation lineup changes in surrounding areas, including the Auxiliary Building.

Fuel handling procedures j

require verification that the SFP area exhaust fans work but give no a

consideration to prer.;ure differences between the SFP area and surrounding areas, including the Auxiliary Building.

Operations, Engineering, Maintenance, and Nuclear Fuel Management personnel were accustomed to thinking in these terms and did not give consideration to pressure differences between the SFP area and the Auxiliary Building.

A Root Cause Analysis is under way to review this item and its generic t

implications. The findings of this review will be included in a supplement to this report.

The missed surveillance was the result of personnel error on the part of the i

responsible Functional Surveillance Test Coordinator. He had erroneously counted partial performance of the STP on July 18, 1995 as complete performance and so had changed the schedule of the test from December 1995 to January 1997.

III.

ANALYSIS OF EVENT

a As noted above, the UFSAR analysis for a fuel handling accident assumes that all releases will pass through a charcoal filter.

Section 14.18.3.2.d of the UFSAR also states that, "The charcoal filters have an absorption efficiency of i

90 percent for inorganic iodine and 70 percent for organic iodine." The analysis calculates a thyroid dose at the site boundary of 3.39 Rem.

With the door ajar as found, the System Engineer estimated one percent air leakage from

]

the SFP area. This would raise the dose at the site boundary to approximately

)

3.58 Rem thyroid and 0.16 Rem whole body. While slightly higher than calculated in the UFSAR, this is still considerably lower than 10 CFR Part 100 limits and well below the UFSAR calculated site boundary thyroid dose of 14 06 Rem from a fuel handling accident in containment. The UFSAR analysis also assumes that the damaged fuel assembly has the highest activity in the core.

The fuel actually being moved at the time of discovery of this condition was considerably less active than assumed in the UFSAR analysis, Even if all the iodine released during a fuel handling accident bypassed the j

l charcoal filters, the site boundary dose would be no greater than 22.25 Rem j

thyroid and 0.72 Rem whole body, which is considerably less than 10 CFT Part 100 limits.

_~...

,U.S. NUCLEAR RE;ULATORY COMMISSION (4-95)

LICENdEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME (1)

DOCKET L.A NutsBER 14)

PAGE (3)

YEAR l SEQUENTIAL REVISION d

l NUMBER NUMBER Calvert Cliffs, Unit 1 05000 317 97

- 001 -

00 05 OF 06 TEXT (it more space se tuguroa une -i.e

.! copes of AIRC Form 3664 (17)

I This item was reportable under 10 CFR 50.73 (a) (2) (ii) (B) as a condition outside the plant's design basis and under 10 CFR 50.73 (a) (2) (1) (B) as a l

condition prohibited by the plants Technical Specifications, j

There were ne safety consequences resulting from the missed STP.

The partial test verified the operability of the fans and HEPA filters. The complete test was successfully performed on January 24, 1997. Apart from this event, there is no evidence that the SFP ventilation system was incapable of performing its i

safety function without being declared inoperable between the time the STP expired and was performed again.

Fuel movement is required by procedure to stop if the SFP exhaust fans are incapable of performing their safety function. This item was reportable under 10 CFR 50.73 (a) (2) (1) (B) a s.*.

condition prohibited by the plant's Technical Specifications.

IV.

CORRECTIVE ACTIONS

A, Upon notification of the air leakage from the SFP area, the Control Room immediately had the open door shut and, following review of SFP ventilation system flow requirements, suspended fuel movement in the SFP area.

B.

Appropriate procedures are being revised to require verification that two Auxiliary Building air supply fans are operating or that the SFP area is maintaining negative pressure relative to the Auxiliary Building whenever the SFP ventilation system is required to be operable.

Fuel movement will not resume until revision of the procedures and appropriate training of fuel handling personnel is completed.

Fuel movement will be suspended in the event of the loss of one of two operating air supply fans, or a change in Auxiliary Building ventilation lineup with a single fan operating.

C.

A Root Cause Analysis is under way to deteru.ine casual factors and generic implications for this event. The findings of this review will be included in a supplement to this report.

D.

The STP was performed on January 24, 1997.

E.

A review of all current STPs is underway to verify that additional STPs have not been missed. The results of this review will be reported in a supplement to this report.

I NRC FORM 366A

~

U.S. NUCLEAR RE ULATORY COMMISSION (4-95)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION F ACILITY NAlff (1)

DOCKET LER NutfGER (6)

PAGEp)

YEAR SEQUENTIAL REVISaON NutfGER Nutf9ER Calvert Cliffs, Unit 1 05000 317 97

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00 06 OF 06 Mmom nonce a renwers. uee m copes of NRC Form 366A)(17)

V.

ADDITIONAL INFORMATION

A.

Affected Component Identification:

IEEE 803 IEEE 805 f

Component or System EIIS Funct System ID SFP Ventilation Fan FAN VG SFP Ventilation Filter FLT VG 4

i Auxiliary Building Fan FAN VF l

Auxiliary Building Radiation Monitor RE VF B.

Previous Similar Events

4 Previous similar events will be discussed in a supplement to this report.

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