05000483/LER-2018-004, Violation on TS 3.8.1 AC Sources - Operating

Violation on TS 3.8.1 AC Sources - Operating

ML18295A415
Person / Time
Site:	Callaway
Issue date:	10/22/2018
From:	Bianco F Ameren Missouri, Union Electric Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
ULNRC-06466 LER 2018-004-00
Download: ML18295A415 (8)

LER-2018-004, Violation on TS 3.8.1 AC Sources - Operating

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
4832018004R00 - NRC Website

text

Ameren MISSOURI Caliaway Plant October 22, 2018 U LNRC-06466 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington. DC 20555-0001 10 CFR 50.73 Ladies and Gentlemen:

DOCKET NUMBER 50-483 CALLAWAY PLANT UNIT 1 UNION ELECTRIC CO.

RENEWED FACILITY OPERATING LICENSE NPF-30 LICENSEE EVENT REPORT 2018-004-00 VIOLATION OF TS 3.8.1 AC SOURCES - OPERATING The enclosed Licensee Event Report is submitted in accordance with 10CFR5O.73(a)(2)(i)(B) to report instances where a violation of Technical Specification (TS) 3.8.1, AC Sources Operating. occwTed due to unrecognized inoperability of the train B emergency diesel generator (DG) during performance of a periodic maintenance activity.

If you have any questions concerning this LER, please contact Torn Elwood. Supervising Engineei-,

Regulatory Affairs and Licensing at (314) 225-1905.

Sinc ely F eden tanco Senior Director, Nuclear Operations

Enclosure:

LER 20 18-004-00 8315 County Road 459 Steedman, MO 65077 AmerenMissouri.com

ULNRC-06466 October 22, 2018 Page 2 of 3 cc:

Mr. Kriss M. Kennedy Regional Administrator U. S. Nuclear Regulatory Commission Region IV 1 600 East Lamar Boulevard Arlington. TX 76011-4511 Senior Resident Inspector Call away Resident Office U.S. Nuclear Regulatory Commission 8201 NRC Road Steedman, MO 65077 Mr. L. Joirn Kios Project Manager, Callaway Plant Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Mail Stop 09E3 Washington. DC 20555-0001

ULNRC-06466 October 22, 2018 Page 3 of 3 Index and send hardcopy to QA File A 160.0761 Hardcopy:

Certrec Corporation 6100 Western Place, Suite 1050 Fort Worth, TX 76107 (Certrec receives ALL attachments as long as they are non-safeguards and may be publicly disclosed.)

Electronic distribution for the following can be made via LER ULNRC Distribution:

F. M. Diya B. L. Cox F. J. Bianco T. F. Henmann S. P. Banker R. C. Wink T. B. Elwood K. A. Mills L. E. Eltel K. J. Tipton Corporate Oversight Corporate Communications NSRB Secretary Performance Improvement Coordinator Resident Inspectors (NRC)

STARS Regulatory Affairs Mr. Jay Silberg (Pillsbury Winthrop Shaw Pittman LLP)

Missouri Public Service Commission

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3. Page Callaway Plant Unit 1

, 05000483 1 OF 5

4. Title ViolationufTS 3.8.t.AC Sources Oneratiria

5. Event Date

6. LER Number

7. Report Date

8. Other FacUlties Involved

Sequential Rev I

Facility Name Docket Number Month Day Year YEAR Number No Month Day Year 05000 I

t

08 24 2078 2018

- 004

- 00 10 22 2018 Facility Name Docket Number

9. Operating Mode

kBSTRACT (Limit to 1400 spaces. i.e approximately 14 single-spaced typewritten )nes)

On 08/24/2018, during a scheduled periodic maintenance activity to filter stored diesel fuel oil for the train B emergency diesel generator, the Operability of the affected diesel generator was questioned. Subsequent evaluation concluded that due to (1) use of a non seismically-qualified filtration flowpath, and (2) exposure of diesel fuel oil transfer system components to postulated tornado missiles during the maintenance activity, the activity rendered the affected diesel generator inoperable. Two instances were identified within the previous 3 years where the maintenance activity had caused unrecognized past inoperability of the train B standby diesel generator for a duration that exceeded the 72-hour restoration Completion Time specified per Technical Specification (IS) 3.8.1 Required Action B.4. These instances are being reported as violations of TS 3.8.1 in accordance with 10 CFR 50.73(a)(2)(i)(B).

Corrective actions are being taken to establish appropriate administrative controls for removal of affected missile barriers, and to assure that the TS implications of temporary system modifications (such as stored fuel oil filtration) are properly evaluated.

Until permanent corrective actions are implemented, remedial actions have been taken to prohibit filtration of stored fuel oil for an Operable DG.

NRC FORM 366 (04-2018)

1.

DESCRIPTION OF STRUCTURE(S), SYSTEM(S) AND COMPONENT(S):

The Callaway Plant emergency diesel generator (DG) fuel oil storage and transfer system (EDEFSTS) [EIIS Code: DE]

provides onsite storage and transfer of fuel oil to the DG engines [EflS Code: ED]. For each of the two DGs, a transfer pump [EIIS Code PJ transfers fuel oil from the DGs fuel oil storage tank [EIIS Code: 1K] to its associated day tank [EIIS Code: TKJ.

The design of the EDEFSTS is subject to 10 CFR 50 Appendix A, General Design Criterion (GDC) 2, which states in part that structures, systems, and components important to safety shall be designed to withstand the effects of natural phenomena such as earthquakes, tornadoes, hurricanes, floods, tsunami, and seiches without loss of capability to perform their safety functions. The design bases listed in Final Safety Evaluation Report (FSAR) section 9.5.4.1.1, which describes Callaways compliance with GDC 2, states in part, The EDEFSTS is protected from the effects of natural phenomena, such as earthquakes, tornadoes, hurricanes, floods, and external missiles.

Regarding equipment that is credited in safety analyses for mitigation of a design-basis, large break loss-of-coolant accident (LBLOCA), in addition to the requirements of GDC 2, the single failure assumptions in FSAR 3.1.2 state in part, For a LBLOCA, for additional safety no credit is taken for the functioning of non-seismic Category components.

2.

INITIAL PLANT CONDITIONS

At the time of the initial identification of an issue with Operability of DGs during performance of a scheduled preventive maintenance activity (beginning on August 24, 201 8), the plant was in Mode 1 at 100% power. No inoperability of other structures, systems or components (SSCs) contributed to the condition.

3.

EVENT DESCRIPTION

On August 24, 2018, the site NRC Senior Resident Inspector observed a scheduled preventive maintenance activity for filtration of fuel oil for the train B DG, and questioned whether the DG should be considered Operable during the filtration activity.

In Modes 1,2,3 and 4, Technical Specifications (IS) Limiting Condition for Operation (LCO) 3.8.1, AC Sources Operating, requires two (i.e., both) redundant DG trains to be Operable. Regarding the EDEFSTS, TS LCO 3.8.3, Diesel Fuel Oil, Lube Oil, and Starting Air, states in part that the diesel fuel oil storage subsystem shall be within limits for each required DG when the associated DG is required to be Operable. These limits include a minimum required volume of stored diesel fuel oil.

The filtration activity had begun at 0753 CDT on 08/20/2018, and was finished at 1755 CDT on 08/24/201 8. During this period, stored fuel oil for the train B DG was dewatered and sampled between 0607 CDT and 1145 CDT on 08/22/2018, in order to satisfy Technical Specifications (IS) Surveillance Requirement (SR) 3.8.3.5 (which requires checking for and removing accumulated water from each fuel oil storage tank at a periodic frequency).

In response to the Senior Resident Inspectors question, plant staff evaluated the filtration activity and also the dewatering/sampling activity.

In consideration of the following, it was determined that Operability of the affected DG could not be supported during the performance of either activity.

1.

Performance of either the filtration or the dewatering/sampling activity involves the use of a sampling line, which is accessed by removing a small steel hatch in the vault cover for the underground fuel oil storage tank for the affected DG. The steel hatch serves as a barrier to tornado missiles. The plants hazard barrier control procedure incorrectly allowed the steel hatches to be removed without imposing administrative controls. When a hatch is removed, the electrical power conduits that supply the affected DGs EDEFSTS transfer pump are(04-2018)

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sponsor, and a person is not required to respond to the information collection

1. FACILITY NANIE

2. DOCKET NUMBER

3. LER NUMBER YEAR SEQUENTIAL REV Callaway Plant Unit 1 05000-483 NUMBER NO 2018

- 004

- 00 exposed to potential damage from postulated tornado missiles. Such damage would have the potential to preven the transfer pump from performing its safety-related support function, thereby preventing the affected DG from performing its safety-related function 2.

Performance of the filtration activity involves connecting a filtration skid between the sampling line and the fill line (used for fuel oil deliveries) for the underground fuel oil storage tank. A pump in the filtration skid takes a suction on the sampling line, and the flow of fuel oil is then directed through a bank of filtration vessels before being returned to the tank through the fill line. As neither the filtration skid nor its connecting hoses are seismically qualified, they cannot be credited to retain their integrity during a LBLOCA event.

A casualty affecting the filtration skid or connecting hoses downstream of the pump would have the potential to spill a large quantity of the stored fuel oil credited to meet the limits of TS 3.83.

It was thus determined that the procedure for performing the filtration activity did not provide adequate controls to ensure that actions would be taken in a timely manner to terminate such a spill before the remaining quantity of stored fuel oil would be below the limits oilS 3.83, which would in turn cause entry into TS 38.1 Required Action Fl. Consequently, the associated DG would have to be considered inoperable, as entry into TS 38.3 Required Action F.1 immediately requires declaring the associated DG inoperable.

In the three years prior to discovery of the condition, the filtering activities were performed on 3 occasions, and the dewatering/sampling activities were performed on 80 occasions, resulting in 41 periods of unrecognized inoperability for the train A DG and 42 periods of unrecognized inoperability for the train B DG. On 81 of the occasions, the affected DG was restored to Operable status in less than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, which satisfied the Completion Time for restoration of a single inoperable DG per TS 3.8.1 Required Action B.4. However, as shown below, there were two instances where the period o unrecognized inoperability for the train B DG exceeded 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

Activity Start End Duration, Hours Filtration 02/29/2016 1230 CDT 03/04/2016 1142 CDT 9520 Filtration 08/20/2018 0753 CDT 08/24/2018 1755 CDT 106.03 On these occasions, the unrecognized noperability of the B EDG resulted in a violation of TS 3.8.1 4.

ASSESSMENT OF SAFETY CONSEQUENCES

The unrecognized inoperability of the affected DG during performance of filtration and dewatering/sampling activities is of minor safety significance.

A review of past performances of the filtration and dewatering/sampling activities found that during the three years prior to discovery of the condition, the unrecognized inoperability of an affected DG did not occur when the redundant DG was inoperable. Based on the above, the condition did not cause a loss of safety function for the onsite AC power sources.

Additionally, during each occurrence of unrecognized DG inoperability, the turbine-driven auxiliary feedwater pump (a required redundant feature for the motor-driven auxiliary feedwater pumps) remained Operable, and two sources of offsite power were available to supply safety-related equipment. Furthermore, during the periods of unrecognized DG inoperability, no actual hazards occurred that would have prevented the affected DG from performing its required safety function.

5.

REPORTING REQUIREMENTS

This LER is submitted pursuant to 10 CFR 50.73(a)(2)(i)(B) to report a condition or operation in violation of Technical Specifications.

Page 3of5 6.

CAUSE OF THE EVENT

The failure to recognize that the affected DGs were inoperable during performance of the filtration and dewatering/sampling activities may be attributed to the following causes.

1.

An engineering evaluation that was performed in 1999 determined that the rain covers for the steel hatches in the vault lids for the underground fuel oil storage tanks could be removed without imposing administrative controls. During preparation of the plants hazard barrier control procedure, the engineering evaluation was incorrectly applied to exempt the removal of the steel hatches from administrative controls.

2.

The procedure for filtration of the stored fuel oil required that a continuous Security watch would be established in the vicinity of the filtration equipment. Although the procedure directed that Security contact the Control Room if the filtration unit were to develop a leak, the assigned Security personnel were not authorized or qualified to mitigate a leak that could result from a hazard adversely affecting the skid, and the required response time for an Operator to mitigate a leak was not specified.

7.

CORRECTIVE ACTIONS

To address the causes of the condition, the following remedial actions are being taken.

1.

The design information for the steel hatches is being revised to describe the credited function performed by the hatches as missile barriers, and the plants hazard barrier control procedure is being revised to require administrative controls for removal of the hatches. Written instructions for the periodic filtration and dewatering/sampling of the stored fuel oil are also being revised to clearly state that removal of the steel hatches is an impairment of a missile barrier that requires administrative controls to be in place in accordance with the hazard barrier procedure.

2.

The plant procedure for temporary system modifications (such as filtration of stored fuel oil) is being revised to assure that their TS implications are properly evaluated. Until permanent corrective actions are implemented, remedial actions have been taken to prohibit filtration of the stored fuel oil for an Operable DG.

8.

PREVIOUS SIMILAR EVENTS

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