05000261/LER-2010-006, Pressurizer Heaters Inoperable Longer than Allowed Due to Inadequate Procedure
| ML102810499 | |
| Person / Time | |
|---|---|
| Site: | Robinson  |
| Issue date: | 10/04/2010 |
| From: | Saunders W Progress Energy Carolinas |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| RNP-RA/10-0105 LER 10-006-00 | |
| Download: ML102810499 (4) | |
| 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)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 2612010006R00 - NRC Website | |
text
10 CFR 50.73 Progress Energy Serial: RNP-RA/10-0105 OCT 0 4 2010' Attn: Document Control Desk United States Nuclear Regulatory Commission Washington, DC 20555-0001 H. B. ROBINSON STEAM ELECTRIC PLANT, UNIT NO. 2 DOCKET NO. 50-261/LICENSE NO. DPR-23 LICENSEE EVENT REPORT NO. 2010-006-00 PRESSURIZER HEATERS INOPERABLE LONGER THAN ALLOWED DUE TO INADEQUATE PROCEDURE Ladies and Gentlemen:
The attached Licensee Event Report is submitted in accordance with the requirements of 10 CFR 50.73. Should you have any questions regarding this matter, please contact Mr. C. A. Castell at (843) 857-1626.
Sincerely, W. Scott Saunders Plant General Manager H. B. Robinson Steam Electric Plant, Unit No. 2 WSS/psf Attachment c"
L. A. Reyes, NRC, Region II T. J. Orf, NRC, NRR NRC Resident Inspector Progress Energy Carolinas, Inc.
Robinson Nuclear Plant, 3581 West Entrance Road Hartsville, SC 29550
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES 08131/2010 (9-2007)
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 LICENSEE EVENT REPORT (LER) fed back to industry. Send comments regarding burden estimate to the Records and FOIA/Privacy Service Branch (T-5 F52), U.S. Nuclear Regulatory Commission, (See reverse for required number of Washington, DC 20555-0001, or by internet e-mail to infocollects@nrc.gov, and to digits/characters for each block) the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to I resoond to the information collection
- 3. PAGE H. B. Robinson Steam Electric Plant, Unit No. 2 05000261 1 OF 3
- 4. TITLE Pressurizer Heaters Inoperable Longer Than Allowed Due to Inadequate Procedure
- 5.
EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED SFACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR SEQUENTIAL REV NUMBER NO MONTH DAY YEAR 05000 FACILITY NAME DOCKET NUMBER 08 04 2010 2010 -
006 00 10 04 2010 05000
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)
- 9. OPERATING MODE El 20.2201(b)
El 20.2203(a)(3)(i)
[E 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) 1 El 20.2203(a)(1)
El 20.2203(a)(4)
El 50.73(a)(2)(ii)(B)
El 50.73(a)(2)(viii)(B)
El 20.2203(a)(2)(i)
E]
50.36(c)(1)(i)(A)
El 50.73(a)(2)(iii)
El 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL 11 20.2203(a)(2)(ii)
El 50.36(c)(1)(ii)(A)
El 50.73(a)(2)(iv)(A) El 50.73(a)(2)(x)
E]
20.2203(a)(2)(iii)
El 50.36(c)(2)
El 50.73(a)(2)(v)(A)
El 73.71(a)(4) 100%
El 20.2203(a)(2)(iv)
El 50.46(a)(3)(ii)
El 50.73(a)(2)(v)(B)
El 73.71 (a)(5)
El 20.2203(a)(2)(v)
El 50.73(a)(2)(i)(A)
El 50.73(a)(2)(v)(C)
E]
OTHER Specify in Abstract below 20.2203(a)(2)(vi)
E 50.73(a)(2)(i)(B)
El 50.73(a)(2)(v)(D) or in capability without compromising independence between emergency buses. Based on the investigation of this event, it appears that the effects of Emergency Bus E-1 [EF:BU] being unavailable, causing the low pressurizer level heater cutoff circuit to be de-energized, were not recognized at that time. EDG A' and EDG 'B' were considered redundant and changes were validated by performing assessments of EDG 'A' only.
The investigation further concluded that the testing methodology has masked the issue with the low pressurizer level heater cutoff circuit due to maintaining Instrument Bus 1 energized by the Dedicated Shutdown Diesel Generator (DSDG) [EC:DG] in accordance with plant procedures. Although the DSDG would in most cases ensure that the pressurizer heaters could be powered from emergency power, the DSDG is not included for TS operability.
Safety Significance
The investigation concluded that the safety significance of this condition is low due to the limited time EDG 'A' has been out-of-service (other than surveillance testing). In addition, if HBRSEP, Unit No. 2, were to experience a Loss of Offsite Power with EDG 'A' unavailable, the required pressurizer heaters could have been energized by utilizing a combination of the 'B' EDG and the DSDG.
.IV. CORRECTIVE ACTIONS
Completed Corrective Actions
As an interim action, Operations issued a caution tag on EDG 'A' that required entering the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> required action for Condition C of LCO 3.4.9 if EDG 'A' was inoperable.
EPP-21, "Energizing Pressurizer Heaters from Emergency Busses," was subsequently revised to ensure the pressurizer heaters could be powered from the 'B' EDG, which allowed removal of the caution tag.
Planned Corrective Actions
The changes to EPP-21.require lifting a lead to be able to power the pressurizer heaters from
'B' EDG. Therefore, it is currently planned to make physical modifications to eliminate the need for lifting a lead. This modification is currently scheduled for completion by May 31, 2013.
V. ADDITIONAL INFORMATION
Previous Similar Events:
License Event Reports (LERs) for HBRSEP, Unit No. 2, were reviewed from the past 10 years. No events were identified as being similar to the event described in this LER.