05000483/LER-2019-002, Mode 4 Entry with Inoperable Auxiliary Building Pressure Boundary
| ML19191A232 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 07/10/2019 |
| From: | Kanuckel L Ameren Missouri, Union Electric Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| ULNRC-06522 LER 2019-002-00 | |
| Download: ML19191A232 (8) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability |
| 4832019002R00 - NRC Website | |
text
Aiii#ien Callaway Plant MISSOURI July 10, 2019 ULNRC-06522 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-000 1 10 CFR 50.73 Ladies and Gentlemen:
DOCKET NUMBER 50-483 CALLAWAY PLANT UNIT 1 UNION ELECTRIC COMPANY RENEWED FACILITY OPERATING LICENSE NPF-30 LICENSEE EVENT REPORT 2019-002-00 MODE 4 ENTRY WITH INOPERABLE AUXILIARY BUILDING PRESSURE BOUNDARY The enclosed license event report is submitted in accordance with 10 CFR 50.73(a)(2)(i)(B) to report an operation or condition prohibited by Technical Specifications, entry into Mode 4 from Mode 5 with an inoperable auxiliary building pressure boundary.
This letter does not contain any new commitments.
Sincerely, LQ Leslie H Kanuckel, Director, Nuclear Organizational Effectiveness Enclosure LER 20 19-002-00
.EEE
$3 15 County Road 459 Steedman, MO 65077 AmerenMissouri.com
ULNRC-06522 July 10, 2019 Page 2 of 3 cc:
Mr. Scott A. Morris Regional Administrator U. S. Nuclear Regulatory Commission Region IV 1 600 East Lamar Boulevard Arlington, TX 76011-4511 Senior Resident Inspector Callaway Resident Office U.S. Nuclear Regulatory Commission 8201 NRC Road Steedman, MO 65077 Mr. L. John Kios Project Manager, Callaway Plant Office ofNuclear Reactor Regulation U. S. Nuclear Regulatory Commission Mail Stop 09E3 Washington, DC 20555-0001
ULNRC-06522 July 10, 2019 Page 3 of 3 Index and send hardcopy to QA File A160.0761 Hardcopy:
Certrec Corporation 6100 Western Place, Suite 1050 FortWorth,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 Tech Spec ULNRC Distribution:
F. M. Diya T. E. Henniann B. L. Cox F. J. Bianco S. P. Banker L. H. Kanuckel R. C. Wink T. B. Elwood NSRB Secretary STARS Regulatory Affairs Mr. Jay Silberg (Pillsbury Winthrop Shaw Pittrnan LLP)
Missouri Public Service Commission Mr. Dru Buntin (DNR)
Mr. Steve Feeler (DNR)
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 0313112020 (04-2017)
Estimated burden per response to comply with this mandatory collection request:
80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />.
/*.*
Reported lessons learned are incorporated into the licensing process and led back to industry.
Send comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S.
\\
(See Page 2 for required number ofdigits/characters for each block)
Nuclear Regulatory Commission, Washington, DC 20555-0001,
or by e-mail to Infocollects.
?*... 4 Resource©nrc.gov, and to the Desk
- Officer, Office of Information and Regulatory
- Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means (See NUREG-1 022, R.3 for instruction and guidance for completing this form used to impose an information collection does not display a currently valid 0MB control number, http://www.nrc.gov/reading-rm/doc-collections/nurecis/staff/srl0221r31) the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. PAGE Callaway Plant Unit I 05000483 of 5
- 4. TITLE dinPrsurBnunarv
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED I
1 1
1--
FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR SEQUENTIAL1 REV MONTH DAY YEAR NUMBER NO.
05000
1---;i-i -;-
- 1J1 O71O 2019
- 9. OPERA11NG MODE
- 11. ThIS REPORT IS SUBMITTED PURSUANTTO ThE REQUIREMENTS OF 10 CFR: (Check all that apply) 4 0 20.2201(b) i: 202203(a)(3)(i) cj 50.73(a)(2)(ii)(A)
Q 50.73(a)(2)(viii)(A)
D 20.2201(d)
- - D 20.2203(a)(3)(ii)
Q 50.73(a)(2)(ii)(B)
Q 50.73(a)(2)(viii)(B)
D 20.2203(a)(1)
Q 202203(a)(4)
Q 50.73(a)(2)(iii)
C 50.73(a)(2)(ix)(A)
D 20.2203(a)(2)(i)
D 5036(c)(1 )(i)(A)
Q 50.73(a)(2)(iv)(A) 0 5073(a)(2)(x)
- 10. POWER LEVEL D 20.2203(a)(2)(ii)
Q 50.36(c)(1 )(ii)(A)
C 50.73(a)(2)(v)(A)
Q 73.Z1(a)(4)
D 20.2203(a)(2)(iii)
Q 50.36(c)(2)
Q 50.73(a)(2)(v)(B)
Q 73Z1(a)(5) 0%
D 20.2203(a)(2)(iv)
Q 50.46(a)(3)(ii)
Q 50.73(a)(2)(v)(C)
Q 73.77(a)(1) i: 20.2203(a)(2)(v)
D 50.73(a)(2)(i)(A)
Q 50.73(a)(2)(v)(D)
Q 73.77(a)(2)(i) ci 20.2203(a)(2)(vi) 50.73(a)(2)(i)(B)
Q 50.73(a)(2)(vii)
Q 73.77(a)(2)(ii) t: 5073(a)(2)(i)(C) i: OTHER Specify in Abstract below or in NRC Form 366A
- 12. LICENSEE CONTACT FOR THIS LER LICENSEE CONTACT rELEPHONE NUMBER (Include Area Code)
- 13. COMPLETE ONE UNE FOR EACH COMPONENT FIaJLURE DESCRIBED IN ThIS REPORT
CAUSE
SYSTEM ICOMPONENT FACTURER REPORTABLE
CAUSE
SYSTEM J COMPONENT f FACTURER REPORTABLE IZIZ
- zzzjijzz_z_:1jz_z:
- 14. SUPPLEMENTAL REPORT EXPECTED
- 15. EXPECTED MONTH 1 DAY YEAR El YES (lfyes, complete 15. EXPECTED SUBMISSION DATE)
NO SUBMISSION
BSTRACT (Limitto 1400 spaces, Ce., approximately 15 single-spaced typewritten lines) on May I I, 201 9, during mode ascension exiting from Refueling Outage 23, CaHaway Plant entered Mode 4 from Mode 5 vhile not in compliance with Technical Specification 3.7.13, Emergency Exhaust System (EES). Specifically, a door that is a part of the Auxiliary Building pressure boundary was not closed prior to Mode 4 entry. This mode transition was not in compliance with the requirements of LCO 3.0.4. This event was previously reported as an event or condition that could have prevented fulfillment of a safety function per ENS 54061
, but that notification is being retracted.
rhis event was caused by the failure to initiate equipment out of service tracking when a pressure boundary door was impaired. Callaway administrative procedures for control of hazard barriers will be revised to ensure that mode change restrictions associated with hazard barrier impairment are appropriately tracked.
1.
DESCRIPTION OF STRUCTURE(S), SYSTEM(S) AND COMPONENT(S):
The event reported in this LER involves the Emergency Exhaust System tEES) and the auxiliary building pressure boundary. The Emergency Exhaust System (EllS: VF) serves both the auxiliary building and the fuel building. Following a safety injection signal (515), safety related dampers isolate the auxiliary building, and the EES exhausts potentially contaminated air due to leakage from ECCS systems. The Emergency Exhaust System also can filter airborne radioactive particulates from the area of the fuel pool following a fuel handling accident. A design feature of the auxiliary building is a pressure boundary that ensures that post-accident releases of radioactivity into the auxiliary building are processed through the EES prior to release to the environment.
The EES consists of two independent and redundant trains. Each train consists of a heater, a prefilter, a high efficiency particulate air (HEPA) filter bank, an activated charcoal adsorber section for removal of gaseous activity (principally radioiodines), and a fan. Ductwork, dampers, and instrumentation also form part of the system. A second bank of HEPA lIters follows the adsorber section to collect carbon fines.
The Emergency Exhaust System is on standby for an automatic start following receipt of a fuel building ventilation isolation signal (FBVIS) or a safety injection signal (515). Initiation of the 515 mode of operation takes precedence over any other mode of operation. In the 515 mode, the system is aligned to exhaust the auxiliary building.
technical Specification 3.7.13, Emergency Exhaust System (EES), provides the Limiting Condition for Operations, Required Actions and Surveillance Requirements for the EES.
2.
INITIAL PLANT CONDITIONS
At the time of the event, Callaway was being taken from Mode 5 to Mode 4 during mode ascension from Refuel Outage 23.
3.
EVENT DESCRIPTION
Door DSKI 5041, which separates the auxiliary building from the radioactive materials (RAM) storage building (RSB), is identified by APA-ZZ-00750, Hazard Barrier Program, as a fire, pressure, security, missile, and radiation barrier. The pressure boundary function of the door is required to be Operable (or open under Administrative Controls) in Modes I -4 per Technical Specification 3.7.1 3 to maintain Operability of both trains of the Emergency Exhaust System (EES).
DSKI 5041 serves as a part of the Auxiliary Building pressure boundary. There is no Technical Specification requirement or the Auxiliary Building pressure boundary including DSKI 5041 in Modes 5, 6, or with the core offloaded (in No Mode.)
During refueling outages DSKI5O4I is typically blocked open with a ramp installed over its threshold during refueling outages to allow convenient transportation of various tools and equipment from the Radioactive Material (RAM) Storage Building (RSB) to the Reactor Building.
In 2018, as part of preparations for Refuel Outage 23, Fire Protection Impairment Permit (FPIP) 28523 was written solely to track DSKI5O41 being open during Modes 5, 6, and No Mode. The FPIP included Mode 4 restraint in the Description portion of the permit. Preparation of Equipment Out of Service Logs (EOSLs) for the Refuel did not generate an EOSL to track Auxiliary Building pressure boundary inoperabilites, even though an EOSL request was generated for the job task.
EOSL requests are automatically generated based on job location.
\\t 01 57 on April 2, 201 9, Callaway entered Mode 5 from Mode 4 as part of a planned cool down for Refuel 23.
pproximately 30 minutes after entering Mode 5, the Control Room activated FPIP 28523 to authorize the opening of DSKI 5041
. Job I 751 411 9.51 0 was then taken to InProgress which opened DSKI 5041 and installed a ramp weighing Page 2 of 5
approximately 250 pounds over its threshold. The Job included a task which would remove the ramp and close the door.
\\t the time that FPIP 28523 was activated, the ramp removal and door closure task was scheduled as a Mode 4 predecessor to be worked on May 2, 201 9, prior to Mode 4 entry.
\\s Refuel 23 progressed, emergent work required additional tool support in the Reactor Building and caused delays for entering Mode 4. DSKI 5041 remained open to support tool movement for this work. On May I I, 201 9, Callaway transitioned the plant from Mode 5 to Mode 4. Earlier in the day, the scheduling tie between the ramp removal/door Dlosure task and Mode 4 was broken. This break was made because there was no EOSL attached to the Job and no mode restraint on the task.
Prior to the mode change, the on-shift operations crew had completed the Mode 5 to Mode 4 checklist contained in Drocedure ODP-ZZ-00014, Operational Mode Change Requirements. As part of the checklist, a review of EOSLs and EDP-ZZ-041 07, HVAC Pressure Boundary Control, were performed. An operations supervisor also performed a walk iown of Auxiliary Building pressure boundary doors, but excluded doors located in Contaminated Areas.
\\ review of FPIPs was not required by ODP-ZZ-00014 but was performed by the crew prior to entering Mode 4.
It was not dentified during the review that FPIP 28523 for DSKI 5041 was a Mode 4 restraint.
Following the Mode change, a fire protection engineer identified during an FPIP review that door DSKI 5041 was blocked pen. The issue was brought to the attention of the control room staff, who dispatched the primary operator to investigate.
DSK15041 was confirmed to be open with a ramp installed across its threshold. Atthis time, the control room entered echnical Specification 3.7.13 Required Action B.1 for both trains of EES being inoperable due to an inoperable Auxiliary 3uilding pressure boundary. The ramp was removed and DSKI 5041 was closed. Once the door was confirmed closed, technical Specification 3.713 was exited. The plantwas in Mode 4 with both trains of EES inoperable for 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and 51 iiinutes.
4.
ASSESSMENT OF SAFETY CONSEQUENCES
Entering Mode 4 with both trains of the emergency exhaust system (EES) inoperable during the ascension from Refuel Outage 23 did not significantly degrade plant safety. Callaways current licensing basis identifies Large Break Loss of Cooling Accident (LBLOCA) as the limiting accident sequence for the EES and the Auxiliary Building pressure boundary.
The radiological consequence analysis for the LBLOCA sequence presented in Chapter 1 5 of the Callaway Final Safety Analysis Report (FSAR) credits the EES for reducing the amount of radioactivity released to the environment post-LBLOCA. The analysis of record assumes that once recirculation of containment sump fluids through the emergency core cooling system (ECCS) and containment spray system is initiated, those systems will leak into the Auxiliary Building.
A portion of those leaked fluids will then flash to steam and become airborne radioactivity in the Auxiliary Building. The EES reduces the quantity of radioactivity released to the environment by exhausting the Auxiliary Building air through the systems safety-grade charcoal filter adsorber beds.
The licensing basis analysis of record for LBLOCA radiological consequences addresses a fission product mix of I 8 isotopes: I 3 noble gasses and 5 iodines. The noble gasses are unaffected by filtration. The safety function of the EES is to reduce the quantity of radioiodines released to the environment post-accident. The EES is credited with 90% efficiency for removal of radioiodines. Radiological consequences to offsite and Control Room locations would be driven by the remaining I 0% of the radioiodines contained in the flashed fraction of the leaked ECCS recirculation fluids.
Calculated radiological consequences for the LBLOCA ECCS release pathway are directly proportional to the radioactive isotopic inventory present in the core at the time of initiation of the accident sequence. The licensing basis analysis of record is based on the equilibrium inventory that would be present at the end of a continuous full-power run for an 18-month fuel cycle. Callaway entered Mode 4 during the mode ascension at the end of Refuel 23. The most recently irradiated fuel assemblies on site had a minimum subcritical decay time of approximately 40 days when Mode 4 was entered with both trains of the EES declared inoperable due to the inoperable pressure boundary. Additionally, at the time of Mode 4 entry, the Callaway core contained 84 feed assemblies that had not yet been in a critical reactor and thus would not have any fission product inventory. Taking into account the reduced iodine inventory due to the decay time and the feed assemblies, the quantity of radioiodines in the Callaway core would be no more than approximately 1/50 of the equilibrium full-power value used in the licensing basis analysis of record. This would make up for the postulated lost benefit of the EES filtration function. Calculated post-LBLOCA consequences would thus continue to be bounded by the values currently reported in the Callaway FSAR. Therefore, entering Mode 4 with both trains of EES inoperable during the ascension from Refuel Outage 23 did not significantly degrade plant safety.
5.
REPORTING REQUIREMENTS
This LER is submitted pursuant to 50.73(a)(2)(i)(B) as an operation or condition prohibited by Technical Specifications.
technical Specification LCD 3.7.1 3 requires that two trains of the Emergency Exhaust System (EES) shall be OPERABLE or the Safety Injection Signal (515) mode of operation during Modes I, 2, 3, and 4. The Bases for Technical Specification 3.7.13 states thatthe Auxiliary Building pressure boundary is required forthe 515 mode of EES operation. LCD 3.7.13 is modified by a Note allowing the Auxiliary Building boundary to be opened intermittently under administrative controls. At he time that Mode 4 was entered during the ascension from Refueling Outage 23, Door DSKI 5041, which separates the
\\uxiliary Building from the Radioactive Material (RAM) Storage Building (RSB), and is also a part of the Auxiliary Building ressure boundary, was open. Additionally, a ramp weighing approximately 250 pounds was installed over the threshold Df DSKI 5041
. This ramp would have obstructed DSKI 5041 and prevented timely closure of the door. The configuration Df DSK1 5041 was outside of the provisions of the administrative controls discussed in the LCD 3.7.1 3 Note and described n the Bases for Technical Specification 3.7.13. Based on this, Callaway was not in compliance with LCD 3.7.1 3 at the ime of Mode 4 entry.
echnical Specification LCD 3.0.4 states that when an LCD is not met, entry into a MODE or other specified condition in he Applicability shall only be made:
a.
When the associated ACTIONS to be entered permit continued operation in the MODE or other specified condition in the Applicability for an unlimited period of time; or b.
After performance of a risk assessment addressing inoperable systems and components, consideration of the results, determination of the acceptability of entering the MODE or other specified condition in the Applicability, and establishment of risk management actions, if appropriate; exceptions to this Specification are stated in the individual Specifications; or c.
When an allowance is stated in the individual value, parameter, or other Specification.
Dondition B ofTechnical Specification 3.7.13 addresses two EES trains inoperable due to inoperable auxiliary building oundary in MODE 1, 2, 3, or 4. Required Action B.1 of Technical Specification 3.7.1 3 requires the restoration of the 3uxiliary building boundary to OPERABLE status within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. Therefore, provision (a) of LCD 3.0.4 was not applicable. Additionally, no risk assessment of entering Mode 4 with the Auxiliary Building pressure boundary inoperable iad been performed, and provision (c) of LCD 3.0.4 is not applicable.
3ased on this, entering Mode 4 while not in compliance with LCD 3.7.13 was an operation or condition prohibited by LCD 3.0.4.
Thus, this event is being reported as an operation or condition prohibited by Technical Specifications in accordance with 50.73(a)(2)(i)(B).
This event was previously reported as an event or condition that could have prevented the fulfillment of a safety function per ENS 54061
, which is being retracted. Testing of the plant configuration that existed at the time of Mode 4 entry has demonstrated that although the configuration of the auxiliary building pressure boundary was not in compliance with the LCD requirements of Technical Specification 3.7.1 3, the pressure boundary was sufficiently intact such that the EES would have been capable of maintaining the auxiliary building at the negative pressure required by the Technical Specification 3.7.13 surveillance requirements. Therefore, the condition reported in this LER would not have prevented the EES from fulfilling its specified safety function, and this LER is not being reported as a condition that would have prevented the fulfillment of a safety function.
6.
CAUSE OF THE EVENT
When the Fire Protection Impairment Permit (FPIP) for Door DSK1 5041 was activated during the mode descent into Refueling Outage 23, an Equipment Out of Service Log (EOSL) for the Mode 4 restraint with an inoperable Auxiliary Building pressure boundary was not created.
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