05000331/LER-2015-006, Regarding HPCI and RCIC Condensate Storage Tank Suction Transfer Inoperable

Regarding HPCI and RCIC Condensate Storage Tank Suction Transfer Inoperable

ML16054A800
Person / Time
Site:	Duane Arnold
Issue date:	02/18/2016
From:	Vehec T Point Beach
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NG-16-0023 LER 15-006-00
Download: ML16054A800 (5)

LER-2015-006, Regarding HPCI and RCIC Condensate Storage Tank Suction Transfer Inoperable

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 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)(x) 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)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(v), Loss of Safety Function
3312015006R00 - NRC Website

text

~~x~era ENERGY~

DUANE ARNOLD February 18, 2016 NG-1 6-0023 10 CFR 50.73 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555-0001 Duane Arnold Energy Center Docket 50-331 Renewed Op. License No. DPR-49 Licensee Event Report 2015-006 Please find attached the subject report submitted in accordance with 10 CFR 50.73. This letter makes no new commitments or changes to any existing

commitments

T. A. Vehec Vice President, Duane Arnold Energy Center NextEra Energy Duane Arnold, LLC cc:

Administrator, Region Ill, USNRC Project Manager, DAEC, USNRC Resident Inspector, DAEC, USNRC NextEra Energy Duane Arnold, LLC, 3277 DAEC Road, Palo, IA 52324

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 0113112017 (02-2014)

,.*.,"'*%Esfimated 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 />.

d7'*Reported lessons learned are incorporated into the licensing process end fed back to industr.

,,t,*.#*Send comments regarding burden estimate to the FOiA, Privacy and Information Collections LICENSEE EV N E O T(LER)

Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by EVEN REORTinternet e-mail to Infocollects.Resource@nrc.gov, aed to the Desk Officer, Office of Information and (See Page 2 for required number of Regulatory Atfairs, NEOB-1O202, (3150-0104), Office of Management andBudget, Washington, DC digis/chractrs fr eah blck)20503.

Ifsa means used to impose an information collection does not display a currently valid 0MB digis/carater foreac blck)control number, the NRC may not conduct or sponsor, and a peruon is not required to respond to, the information collection.

3. PAGE Duane Arnold Energy Center 000311O

4. TITLE HPCI and RCIC Condensate Storage Tank Suction Transfer Inoperable

5. EVENT DATE

6. LER NUMBER I

7. REPORT DATE

8. OTHER FACILITIES INVOLVED FACILITY EVNAME DOCOE NUMBE MOT A ER YEAR SEUMENILREVO MONTH DAY YEAR N/AN/

F821 ACIUTY NAME DOCKET NUMBER 7

23 201-5 2015 006

- 00I 2

18 201 N/A N/A

9. OPERATING MODE

11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)

El 20.2201(b)

El 20.2203(a)(3)(i)

El 50.73(a)(2)(i)(C)

El 50.73(a)(2)(vii)

El 20.2201(d)

El 20.2203(a)(3)(ii)

El 50.73(a)(2)(ii)(A)

El 50.73(a)(2)(viii)(A)

El 20.2203(a)(1)

El 20.2203(a)(4)

El 50.73(a)(2)(ii)(B)

I]

50.73(a)(2)(viii)(B)

_ [] 20.2203(a)(2)(i)

El 50.36(c)(1)(i)(A)

LI 50.73(a)(2)(iii)

El 50.73(a)(2)(ix)(A)

10. POWER LEVEL E] 20.2203(a)(2)(ii)

El 50.36(c)(1)(ii)(A)

LI 50.73(a)(2)(iv)(A)

El 50.73(a)(2)(x)

LI 20.2203(a)(2)(iii)

Lii 50.36(c)(2)

El 50.73(a)(2)(v)(A)

LI 73.71(a)(4) 10%

20.2203(a)(2)(iv)

El 50.46(a)(3)(ii)

[]

50.73(a)(2)(v)(B)

El 73.71 (a)(5) 100%23a()v)

E 07()2(i()E 07()()v()E TE L] 20.2203(a)(2)(vi)

[]

50.73(a)(2)(i)(B)

[]

50.73(a)(2)(v)(D) specifyin Abstract beloworin

I.

Description of Event

On July 23, 2015, while operating at 100% power, with no structures, systems, or components inoperable that contributed to this event, during the performance of Surveillance Test Procedure (STP) 3.5.3-05, RCIC/HPCI Suction Transfer Interlock, the Condensate Storage Tank (CST) Low Level HPCI (High Pressure Coolant Injection) and RCIC (Reactor Core Isolation Cooling) Suction Swap Relay, E41A-K059, as-found time to trip was 19.86 seconds. This was outside the relay design band of 0.0-5.0 seconds and the STP acceptance band of 1.50-2.00 seconds. This condition resulted in the HPCI/RCIC CST suction swap function being inoperable. At the time, this failure was considered a non-TS failure. The relay was recalibrated to meet the STP acceptance band. On October 2, 2015, during the performance of STP 3.5.3-05, the relay once again was found out of tolerance. The relay was tested a second time and was found within the acceptable band.

An immediate operability evaluation determined the suction swap function was operable and an operability evaluation was requested. As compensatory measure, HPCI was aligned to the Torus. While performing troubleshooting on October 8, 2016, it was determined that the suction swap relay was inoperable.

Technical Specification Requirements Technical Specification (TS) 3.3.5.1, Action D.1 requires HPCI to be declared inoperable within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> from the discovery of a loss of the HPCI suction transfer capability if not aligned to the suppression pool.

TS 3.3.5.2, Action D.1 requires RCIC to be declared inoperable within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> from the discovery of a loss of the HPCI suction transfer capability if not aligned to the suppression pool.

TS 3.5.1, Action F.2 requires HPCI to be restored to operable status within 14 days. If this action is not completed, TS require the plant to be in Mode 3 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> of exceeding the 14 days.

TS 3.5.3, Action A.1 requires RCIC to be restored to operable status within 14 days. If this action is not completed, TS require the plant to be in Mode 3 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> of exceeding the 14 days.

Since the suction of RCIC and HPCI are normally aligned to the OST, the inoperability of the suction source swap function makes the supported SSCs (RCIC and HPCI) inoperable from July 23, 2015 until the suction source was manually swapped to the Torus. When this condition was discovered on October 2, 2015, HPCI suction was manually transferred to the Suppression Pool. However, RCIC suction was not transferred to the Suppression Pool and was therefore inoperable from July 23, 2015 until the condition was corrected on October 8, 2015. Both RCIC and HPCI inoperability times exceeded their LCOG duration of 14 days. Therefore, this condition meets the reporting requirements of 10OCFR50.73(a)(2)(i)(B) and I10CFR50.73(a)(2)(v)(A) and (D).

II.

Assessment of Safety Consequences

The safety significance of instrumentation used to initiate transfer of HPCI1 system or RC31C system suction source from the C3STs to the suppression pool is low because the CSTs have a sufficient supply of water for meeting the transient and accident requirements of these systems. Both C3STs are required to be maintained above 8 feet to ensure 75,000 gallons is held in reserve for the HPCI1 system and ROIC(

system and to maintain HP(3I and ROI1C keep fill requirements. At a minimum level of 8 feet there is adequate storage capacity for both HPCI and R(31C to operate at design flow for 35 minutes before the Lo-Lo level is reached. Using additional conservatism, when the O3ST level reaches 6 feet the condensate service pumps trip to ensure no other systems are drawing down the (3ST. Even at a volume corresponding to a starting point of 6 feet both HPCI1 and ROIC( could operate at design flow for 25 minutes before the Lo-Lo level is reached. Under the bounding condition for operation of HPC31, it is assumed during a small break LOC3A that the reactor is depressurized after 10 minutes by operator action via a rapid depressurization using SRVs (Ref. 18). Thus it is expected that the suction transfer would not be required before the operators depressurize the reactor.

In addition, if the Lo-Lo O3ST level is reached, three annunciators are expected.

Annunciator 1 003(3 (D-3) is activated via the time delay relay E4IA-K059. However, annunciators 1 C06A (C-8) and (C3-9) will also occur when O3ST level reaches the Lo-Lo O3ST set point. While not credited as a required operator action, the Annunciator Response Procedure for 1 006A (0-8) and (C;-9) direct an operator action to verify that the Suppression Pool Suction valves for HPCI1 and RCIC( have cycled open. This step directs the operators to open the valves if the automatic function did not occur.

Ill.

Cause of Event

An Apparent Cause Evaluation (ACE) was completed. The ACE determined that the control room operators failed to address the current licensing basis with respect to the C3ST suction swap time delay.

IV.

Immediate Corrective Action

On October 8, 2015, the time delay relay was replaced and subsequently tested satisfactorily.

Corrective Actions for Cause of Event STP 3.5.3-05 was revised to include the current licensing basis for the time delay relay.

V.

Additional Information

Previous Similar Occurrences:

A review of NextEra Energy Duane Arnold Licensee Event Reports from the previous three years found no other instances of events related to the CST suction swap relay failure.

EllS System and Component Codes:

KA - Condensate Storage and Transfer System

Reporting Requirements

This activity is being reported pursuant to the requirements of 10CFR50.73(a)(2)(i)(B) (for both HPCI and RCIC) and 10CFR50.73(a)(2)(v)(A) and (D) (for HPCI).

I.

Description of Event

On July 23, 2015, while operating at 100% power, with no structures, systems, or components inoperable that contributed to this event, during the performance of Surveillance Test Procedure (STP) 3.5.3-05, RCIC/HPCI Suction Transfer Interlock, the Condensate Storage Tank (CST) Low Level HPCI (High Pressure Coolant Injection) and RCIC (Reactor Core Isolation Cooling) Suction Swap Relay, E41A-K059, as-found time to trip was 19.86 seconds. This was outside the relay design band of 0.0-5.0 seconds and the STP acceptance band of 1.50-2.00 seconds. This condition resulted in the HPCI/RCIC CST suction swap function being inoperable. At the time, this failure was considered a non-TS failure. The relay was recalibrated to meet the STP acceptance band. On October 2, 2015, during the performance of STP 3.5.3-05, the relay once again was found out of tolerance. The relay was tested a second time and was found within the acceptable band.

An immediate operability evaluation determined the suction swap function was operable and an operability evaluation was requested. As compensatory measure, HPCI was aligned to the Torus. While performing troubleshooting on October 8, 2016, it was determined that the suction swap relay was inoperable.

Technical Specification Requirements Technical Specification (TS) 3.3.5.1, Action D.1 requires HPCI to be declared inoperable within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> from the discovery of a loss of the HPCI suction transfer capability if not aligned to the suppression pool.

TS 3.3.5.2, Action D.1 requires RCIC to be declared inoperable within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> from the discovery of a loss of the HPCI suction transfer capability if not aligned to the suppression pool.

TS 3.5.1, Action F.2 requires HPCI to be restored to operable status within 14 days. If this action is not completed, TS require the plant to be in Mode 3 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> of exceeding the 14 days.

TS 3.5.3, Action A.1 requires RCIC to be restored to operable status within 14 days. If this action is not completed, TS require the plant to be in Mode 3 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> of exceeding the 14 days.

Since the suction of RCIC and HPCI are normally aligned to the OST, the inoperability of the suction source swap function makes the supported SSCs (RCIC and HPCI) inoperable from July 23, 2015 until the suction source was manually swapped to the Torus. When this condition was discovered on October 2, 2015, HPCI suction was manually transferred to the Suppression Pool. However, RCIC suction was not transferred to the Suppression Pool and was therefore inoperable from July 23, 2015 until the condition was corrected on October 8, 2015. Both RCIC and HPCI inoperability times exceeded their LCOG duration of 14 days. Therefore, this condition meets the reporting requirements of 10OCFR50.73(a)(2)(i)(B) and I10CFR50.73(a)(2)(v)(A) and (D).

II.

Assessment of Safety Consequences

The safety significance of instrumentation used to initiate transfer of HPCI1 system or RC31C system suction source from the C3STs to the suppression pool is low because the CSTs have a sufficient supply of water for meeting the transient and accident requirements of these systems. Both C3STs are required to be maintained above 8 feet to ensure 75,000 gallons is held in reserve for the HPCI1 system and ROIC(

system and to maintain HP(3I and ROI1C keep fill requirements. At a minimum level of 8 feet there is adequate storage capacity for both HPCI and R(31C to operate at design flow for 35 minutes before the Lo-Lo level is reached. Using additional conservatism, when the O3ST level reaches 6 feet the condensate service pumps trip to ensure no other systems are drawing down the (3ST. Even at a volume corresponding to a starting point of 6 feet both HPCI1 and ROIC( could operate at design flow for 25 minutes before the Lo-Lo level is reached. Under the bounding condition for operation of HPC31, it is assumed during a small break LOC3A that the reactor is depressurized after 10 minutes by operator action via a rapid depressurization using SRVs (Ref. 18). Thus it is expected that the suction transfer would not be required before the operators depressurize the reactor.

In addition, if the Lo-Lo O3ST level is reached, three annunciators are expected.

Annunciator 1 003(3 (D-3) is activated via the time delay relay E4IA-K059. However, annunciators 1 C06A (C-8) and (C3-9) will also occur when O3ST level reaches the Lo-Lo O3ST set point. While not credited as a required operator action, the Annunciator Response Procedure for 1 006A (0-8) and (C;-9) direct an operator action to verify that the Suppression Pool Suction valves for HPCI1 and RCIC( have cycled open. This step directs the operators to open the valves if the automatic function did not occur.

Ill.

Cause of Event

An Apparent Cause Evaluation (ACE) was completed. The ACE determined that the control room operators failed to address the current licensing basis with respect to the C3ST suction swap time delay.

IV.

Immediate Corrective Action

On October 8, 2015, the time delay relay was replaced and subsequently tested satisfactorily.

Corrective Actions for Cause of Event STP 3.5.3-05 was revised to include the current licensing basis for the time delay relay.

V.

Additional Information

Previous Similar Occurrences:

A review of NextEra Energy Duane Arnold Licensee Event Reports from the previous three years found no other instances of events related to the CST suction swap relay failure.

EllS System and Component Codes:

KA - Condensate Storage and Transfer System

Reporting Requirements

This activity is being reported pursuant to the requirements of 10CFR50.73(a)(2)(i)(B) (for both HPCI and RCIC) and 10CFR50.73(a)(2)(v)(A) and (D) (for HPCI).