ML110660588
| ML110660588 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 03/28/2011 |
| From: | Kulesa G Plant Licensing Branch II |
| To: | Gillespie P Duke Energy Carolinas |
| Stang J, NRR/DORL, 415-1345 | |
| References | |
| TAC ME3840, TAC ME3841, TAC ME3842, TAC ME5790, TAC ME5791, TAC ME5792, TAC ME5793, TAC ME5794, TAC ME5795 | |
| Download: ML110660588 (6) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON. D.C. 20555-0001 March 28, 2011 Mr. Preston Gillespie Site Vice President Oconee Nuclear Station Duke Energy Carolinas, LLC 7800 Rochester Highway Seneca, SC 29672 SUB,JECT:
OCONEE NUCLEAR STATION, UNITS 1, 2, AND 3, RELIEF REQUEST (RR)
ON-SRP-HPI-03, PROPOSED ALTERNATIVE FOR CERTAIN VIBRATION MEASUREMENT REQUIREMENTS (TAC NOS. ME3840, ME3841, ME3842, MES790. MES791, MES792, MES793, MES794 AND MES79S)
Dear Mr. Gillespie:
By letter dated, March 11,2010, as supplemented March 17.2011, Duke Energy Carolinas, LLC (Duke, the licensee). submitted relief request (RR) ON-SRP-HPI-03 for the fourth 1 O-year interval of Oconee Nuclear Station (ONS), Units 1, 2 and 3, related to the fourth 1 O-year inservice testing (1ST) program interval at the ONS for Units 1, 2, and 3. The ONS Units 1, 2, and 3 fourth 10-year 1ST program interval began on July 1, 2002, and ends on June 30, 2012. The licensee proposed an alternative for certain vibration measurement requirements for vertical line shaft pumps required by the American Society of Mechanical Engineers (ASME), Code for Operation and Maintenance of Nuclear Power Plants (ASME OM Code). Specifically, pursuant to Title 10 of the Code of Federal Regulations (10 CFR), Part SO, Section SO.SSa(a)(3)(ii), the licensee requested to use the proposed alternative as described in their application and supplement, since complying with the current ASME OM Code requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.
Based on the information provided by the licensee, the Nuclear Regulatory Commission (NRC) staff has determined that the licensee's compliance to the 1ST Code of Record would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.
The licensee has adequately addressed all of the regulatory requirements set forth in 10 CFR SO.SSa(a)(3)(ii), and is in compliance with the ASME OM Code's requirements. Therefore, the NRC staff authorizes the use of the proposed alternative in RR ON-SRP-HPI-03 for the remainder of the fourth 1ST interval which ends on June 30,2012.
This relief is authorized by law and will not endanger life or property or the common defense and security, and is otherwise in the public interest giving due consideration to the burden upon the licensee if the requirements were imposed on the facility.
Enclosed is the NRC's Safety Evaluation.
P. Gillespie
- 2 If you have any questions concerning this action, please contact John Stang of my staff at 301-415-1345.
Sincerely, c*(~
Gloria Kulesa, Chief Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-269, 50-270, and 50-287
Enclosure:
Safety Evaluation cc w/encl: Distribution via Listserv
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555*0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REGARDING RELIEF REQUEST ON-SRP-HPI-03 OCONEE NUCLEAR STATION, UNITS 1, 2, AND 3 DUKE ENERGY CAROLINAS, LLC DOCKET NOS. SO-269, SO-270 AND SO-287
1.0 INTRODUCTION
By letter dated March 11,2010 Agencywide Documents Access and Management System (ADAMS), Accession No. ML100770431), as supplemented by letter dated March 17,2011 (ADAMS Accession No. ML110830046), Duke Energy Carolinas, LLC, the licensee, submitted RR ON-SRP-HPI-03 applicable to the fourth 1 O-year inservice testing (1ST) program interval at the Oconee Nuclear Power Station (ONS), Units 1, 2, and 3. The ONS Units 1, 2, and 3 fourth 10-year 1ST program interval began on July 1,2002, and ends on June 30,2012. The licensee requested relief from certain vibration measurement requirements for vertical line shaft pumps required by the American Society of Mechanical Engineers (ASME), Code for Operation and Maintenance of Nuclear Power Plants (ASME OM Code).
Specifically, pursuant to Title 10 of the Code of Federal Regulations (10 CFR), Part SO, Section SO.SSa(a)(3)(ii), the licensee requested to use of a proposed alternative as described in their application and supplement, since complying with the current ASME OM Code requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.
2.0 REGULATORY REQUIREMENTS Section SO.SSa(f), "Inservice Testing Requirements," requires, in part, that ASME Code Class 1, 2, and 3 components must meet the requirements of the ASME OM Code and applicable addenda, except where alternatives have been authorized pursuant to paragraphs (a)(3)(i) or (a)(3)(ii).
In proposing alternatives, a licensee must demonstrate that the proposed alternative provides an acceptable level of quality and safety, or compliance would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety. Section SO.SSa allows the Nuclear Regulatory Commission (NRC) to authorize alternatives to ASME OM Code requirements upon making the necessary findings. The applicable ASME OM Code edition and addenda for ONS Units 1, 2, and 3 is the 1995 Edition through the 1996 Addenda.
The NRC staff's findings with respect to authorizing the alternative to the ASME OM Code are given below.
Enclosure
- 2
3.0 TECHNICAL EVALUATION
3.1 Relief Request ON-SRP-HPI-03 ASME ON Code Section ISTB-4.7.4.b, "Vibration", states that "On vertical line shaft pumps, measurements shall be taken on the upper motor-bearing housing in three approximately orthogonal directions, one of which is the axial direction."
The licensee proposed performing alternative vibration measurements for the following pumps:
1 HPIPU0001 -High Pressure Injection (HPI) Pump 1 HPIPU0002 -HPI Pump 1 HPIPU0003 -HPI Pump 2HPIPU0001 - HPI Pump 2HPIPU0002 -HPI Pump 2HPIPU0003 -HPI Pump 3HPIPU0001 -HPI Pump 3HPIPU0002 -HPI Pump 3HPIPU0003 -HPI Pump In their alternative request, the licensee states the following:
The OM Code required vibration measurements on the upper motor bearing housing for the subject pumps are impractical on the basis of inaccessibility due to location and design features of the motor. Plant design did not include permanent scaffolding or ladders which provide access to the top of the motors for the subject pumps. Also, the upper motor bearing housing is contained within a cone shaped fiberglass shroud which obstructs access to the bearing housing and prevents performance of the axial vibration measurement. In order to perform the required measurements, the component would need to be redesigned to eliminate the shroud or the shroud would have to be removed for each test.
The HPI pumps are considered Group A vertical line shaft pumps. Quarterly vibration readings are taken at two locations on the motor and two locations on the pump. Locations on the motor are at the inboard bearing and approximately midway on the motor housing.
Locations on the pump are the pump inboard bearing and on the pump stand. At each location, vibration measurements are recorded in two approximately orthogonal directions perpendicular to the rotating shaft. These locations have been chosen for monitoring in an effort to identify specific failure modes and have proven to provide early indication of abnormal pump/motor performance. Monitoring of the pump/motor vibrations at these locations will ensure the health of the pump is sufficiently examined.
Application of the OM hydraulic testing criteria along with radial vibration monitoring in the areas described above will provide adequate data for assessing the condition of the subject pumps and for monitoring degradation. Therefore, reasonable assurance of operational readiness for these pumps will be maintained.
- 3 3.2 NRC Staff's Evaluation The licensee has proposed an alternative in lieu of the requirements found in the 1995 Edition through 1996 Addenda of the ASME OM Code Section ISTB-4. 7.4.b for the HPI vertical line shaft pumps 1 HPIPU0001, 1 HPIPU0002, 1 HPIPU0003, 2HPIPU0001, 2HPIPU0002, 2HPIPU0003, 3HPIPU0001, 3HPIPU0002, and 3HPIPU0003.
The OM Code recognizes the value of implementing a vibration analysis strategy for monitoring vertical line shaft pumps by requiring measurements to be taken on the upper motor bearing housing in three orthogonal directions, one of which is the axial direction. The licensee proposes to obtain vibration measurements on the nine HPI vertical line shaft pump motors at two locations; the motor inboard bearing housing area and approximately midway on the motor housing.
Vibration measurements shall be recorded at two orthogonal directions at the stated locations.
The vibration measurements will be tracked and trended along with the hydraulic performance test data. Axial data will not be obtained. The licensee states that axial measurement at the upper motor bearing is difficult due to an obstruction from a fiberglass protective shield which protects the upper motor from the elements. Accessing the upper motor bearing housing would require fabrication of scaffolding and removal of the protective fiberglass shield. This represents a hardship or unusual difficulty without a compensating increase in the level of quality and safety.
Obtaining vibration measurements in two orthogonal directions at the inboard motor bearing area and midway on the motor housing will provide performance data on the upper and lower bearings and overall pump and motor assembly. Parameters such as bearing health, pump/motor unbalance, pump/motor looseness, electrical faults, and resonance issues can be monitored.
The collected data at two orthogonal locations on the motor coupled with the trending of pump hydraulic performance data provides an acceptable alternative for monitoring component health and provides reasonable assurance that the component is operationally ready.
4.0 CONCLUSION
The NRC staff finds that the proposed alternative in request ON-SRP-HPI-03 provides reasonable assurance that high pressure injection pumps 1 HPIPU0001, 1 HPIPU0002, 1 HPIPU0003, 2HPIPU0001, 2HPIPU0002, 2HPIPU0003, 3HPIPU0001, 3HPIPU0002, and 3HPIPU0003 are operationally ready_ All other ASME OM Code requirements for which relief was not specifically requested and approved in the subject request for relief remain applicable.
Accordingly, the NRC staff concludes that the licensee has adequately addressed all of the regulatory requirements set forth in 10 CFR 50.55a(a)(3)(ii), and is in compliance with the ASME OM Code's requirements.
Therefore, the NRC staff authorizes the proposed alternative in RR ON-SRP-HPI-03 for the remainder of the fourth 1ST interval which ends on June 30,2012.
Principle Contributor: Michael Farnan, NRR/DCI Date: March 28, 2011
ML110660588 GKulesa JStang 03/28111 03/28111