L-PI-09-079, License Amendment Request (LAR) to Revise Emergency Diesel Generator (EDG) Test Loads in Surveillance Requirement (SR) 3.8.1.3 and SR 3.8.1.9

License Amendment Request (LAR) to Revise Emergency Diesel Generator (EDG) Test Loads in Surveillance Requirement (SR) 3.8.1.3 and SR 3.8.1.9

ML092230152
Person / Time
Site:	Prairie Island
Issue date:	08/10/2009
From:	Wadley M Xcel Energy
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
L-PI-09-079, TAC ME0086, TAC ME0087
Download: ML092230152 (9)

Text

Xcel Energym L-PI-09-079 10 CFR 50.90 U S Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Prairie lsland Nuclear Generating Plant Units 1 and 2 Dockets 50-282 and 50-306 License Nos. DPR-42 and DPR-60 License Amendment Request (LAR) to Revise Emergency Diesel Generator (EDG) Test Loads in Surveillance Requirement (SR) 3.8.1.3 and SR 3.8.1.9 (TAC Nos. ME0086, ME0087)

Reference:

1. Northern States Power Company, a Minnesota corporation (NSPM),

doing business as Xcel Energy, letter to US Nuclear Regulatory Commission (NRC), "License Amendment Request (LAR) to Revise Emergency Diesel Generator (EDG) Test Loads in Surveillance Requirement (SR) 3.8.1.3 and SR 3.8.1.9", dated November 4, 2008, Accession Number ML083110125.

2. NRC letter to NSPM, "Prairie lsland Nuclear Generating Plant, Units 1 and 2 - Request for Additional Information Related to License Amendment Request for Technical Specifications Changes Related to Revise Emergency Diesel Generator Test Loads in Surveillance Requirement (SR) 3.8.1.3 and SR 3.8.1.9", dated June 26, 2009, Accession Number ML091540227.

In Reference 1, NSPM submitted an LAR for the Prairie lsland Nuclear Generating Plant (PINGP) Units 1 and 2 requesting revisions to the Technical Specifications (TS) for the Prairie lsland Nuclear Generating Plant (PINGP) to increase the 24 month test load for the Unit 1 EDGs, D l and D2, reduce the monthly test load for the Unit 2 EDGs, D5 and D6, and reduce the 24 month test loads for the Unit 2 EDGs. In Reference 2, the NRC Staff requested additional information to support their review of Reference 1. The to this letter provides the responses to the NRC Staff requests for additional information. NSPM submits this supplement in accordance with the provisions of 10 CFR 50.90.

171 7 Wakonade Drive East Welch, Minnesota 55089-9642 Telephone: 651.388.1 121

Document Control Desk Page 2 The supplemental information provided in this letter does not impact the conclusions of the Determination of No Significant Hazards Consideration and Environmental Assessment presented in the November 4,2008 submittal.

In accordance with 10 CFR 50.91, NSPM is notifying the State of Minnesota of this LAR supplement by transmitting a copy of this letter and Enclosure 1 to the designated State Official.

If there are any questions or if additional information is needed, please contact Mr. Dale Vincent, P.E., at 651-388-1 121.

Summarv of Commitments This letter contains no new commitments and no revisions to existing commitments.

I declare under penalty of per'ury that the foregoing is true and correct.

Executed on AUG 1 0 2004 Michael D. Wadley v

Site Vice president, Prairie Island Nuclear Generating Plant Units 1 and 2 Northern States Power Company - Minnesota Enclosures (1) cc:

Administrator, Region Ill, USNRC Project Manager, PINGP, USNRC Resident Inspector, PINGP, USNRC State of Minnesota The Nuclear Regulatory Commission (NRC) Staff has requested the following additional information to support review and approval of the Northern States Power, a Minnesota corporation (NSPM), License Amendment Request (LAR) to amend the Technical Specifications (TS) for the Prairie Island Nuclear Generating Plant (PINGP) to increase the 24 month test load for the Unit 1 emergency diesel generators (EDGs), D l and D2; reduce the monthly test load for the Unit 2 EDGs, D5 and D6; and reduce the 24 month test loads for the Unit 2 EDGs (Reference 1). NRC questions are shown in bold.

NRC request for additional information (RAI) background information Page 15 of 30 of the LAR dated November 04, 2008, states:

The design report did invoke Regulatory Guide (RG) 1.9, "Selection, Design and Qualification of Diesel Generator Units Used As Standby (On-site) Electric Power Systems at Nuclear Power Plants", Revision 2, December 1979, and RG 1.I 08, "Periodic Testing of Diesel Units Used As On-site Electric Power Systems at Nuclear Power Plants", Revision 1, August 1977; however, they were applied for design purposes and not committed to for operation or surveillance testing. The LAR which incorporated D5 and D6, Reference 7, submitted March 20, 1992, did not reference any regulatory guidance as the basis for the proposed EDG surveillance requirements. Likewise, license amendments 103 and 96, Reference 3, which approved use of D5 and D6 did not cite any regulatory guidance as the basis [for] the EDG surveillance test requirements.

The NRC staff has identified the following documents that demonstrate that the licensee intends to comply with RG 1.9:

I. Page 8.4-9 of Revision 29 of the PINGP Updated Safety Analyses Report (USAR) states that the Unit 2 EDGs meet the requirements of RG 1.9, Revision 2, except portions of the 1984 Edition of the Institute of Electrical and Electronics Engineers, Inc. (IEEE) Standard 387 were implemented in the factory testing.

RG 1.9 Revision 2 provides testing guidelines. Specifically, Section C Position 14 states: "Load equal to the continuous rating [of EDG] should be applied for the time required to reach engine temperature equilibrium, at which time, the rated short-time load should be applied for a period of two hours. Immediately following the 2-hour short-time load test, load equal to the continuous rating should be applied for 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br />." The PINGP USAR does not take exception to any sections of RG 1.9, Revision 2.

Page 1 of 7 NSPM

2. The LAR submitted to the NRC on October 29,2007 (ADAMS Accession No. ML073020289) to add power factor testing to the EDG 24-hour test cites the following:

The proposed TS change is consistent with the guidance provided in NUREG-1431, "Standard Technical Specifications, Westinghouse Plants", Revision 3.1 (NUREG-1431), SR 3.8.1.14. This change is acceptable because it is more restrictive than the current TS and is consistent with the intent of Regulatory Guide (RG) 1.9, "Application and Testing of Safety-Related Diesel Generators in Nuclear Power Plants", Revision 4.

3. The LAR submitted to the NRC on August 16,2007 (ADAMS Accession No. ML072320401) to Increase the Unit 1 EDG Monthly Test Load identified RG 1.9 Rev. 4 as "Applicable Regulatory Requirements/CriteriaV and specifically cited consistency with the guidance of RG 1.9, Revision 4, Section C, Regulatory Position 2.2.3, "Load Run (Load Acceptance) Test."

4. Nuclear Management Company, LLC (NMC) (a predecessor license holder to NSPM) submitted a LAR for extension of TS 3.8.1, "AC Sources-Operating,"

Emergency Diesel Generator Completion Time, dated November 21, 2005 (ADAMS Accession No. ML053260088). Page 32 of 33 of this application provides the following information in section 5.2 "Applicable Regulatory Requirements/Criterial':

Regulatory Guide 1.9, "Selection, Design and Qualification of Diesel Generator Units Used as Standby (Onsite) Electric Power Systems at Nuclear Power Plants." This Regulatory Guide describes an acceptable basis for the selection of diesel generator sets of sufficient capacity and margin to implement 10 CFR 50 Appendix A General Design Criterion 17.

The changes proposed in the license amendment request will allow an emergency diesel generator to be inoperable for 14 days (7 days more than the current Technical Specifications allow). These changes do not impact the capacity or margin of the emergency diesel generators; thus this license amendment request does not change the plant compliance with this Regulatory Guide.

5. The NRC staff issued PlNGP License Amendment Nos. 103 and 96 dated December 17, 1992 (ADAMS Accession No. ML022240504) based on the testing frequency and parameters submitted by the licensee in the amendment request dated March 20, 1992. The NRC staff approval of the amendment request delineates that TS section 4.6.A.3.c is revised to add 18-month full load carrying capacity tests of each EDG for an interval of not less than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, of which 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> are at a load equal to 105 -1 10 percent of the continuous rating of an EDG and 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br /> are at a load equal to 90 -100 percent of the continuous rating. This is in compliance with RG 1.9 Revision 2.

The TS Basis document included with the submittal cites RG 1.9 as a Page 2 of 7 NSPM compliance guide. The proposed test values satisfy the intent of RG 1.9 Revision 2 Section C Position 14. The NRC staff noted in the safety evaluation that the allowed outage time for the EDG was not reduced from seven days to the (then existing) criterion of three days due to the diversity in design and ratings provided by the D5 and D6 EDGs, and the increased reliability of the onsite power supply.

Requests for Additional Information

1. Describe the differences between the apparent compliance with RG 1.9 cited in the above examples of LARS and the statements made in the proposed LAR dated November 04, 2008. Specifically, describe how the proposed changes for reducing the 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and the 22 hour2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br /> testing ranges for EDGs D5 and D6 maintain compliance with the requirements of RG 1.9.

NSPM response:

NSPM and the predecessor PlNGP licensee organizations, Northern States Power Company (NSP) and Nuclear Management Company (NMC)', committed to follow the Atomic Energy Commission Safety Guide 1.9 for Unit 1 EDG design considerations and committed to follow NRC Regulatory Guide (RG) 1.9, Revision 2, for Unit 2 EDG design considerations. Design considerations include provisions for vendor and site acceptance testing prior to declaring the EDGs as operational to support plant operations. NSPM and its predecessor organizations have used various revisions of RG 1.9 as a standard for comparison for various facets of EDG testing as will be demonstrated below. NSPM has not identified any commitments to test PlNGP EDGs in accordance with the guidance of any RG 1.9 revision.

In item 1 of the request for additional information (RAI) background information provided above, the NRC cites the USAR which states that RG 1.9, Revision 2 is met. This statement in the USAR is consistent with the commitment made in the design report submitted for the proposed Unit 2 EDGs on November 27, 1990 (Reference 2), which was cited in the LAR dated November 4, 2008 (Reference 1). The design report stated that the commitment to Regulatory Guides, including RG 1.9, were "for design, procurement, fabrication, and construction only: operational and surveillance commitments will be made through the License Amendment Request." This is consistent with the context of the USAR discussion on page 8.4-9 which discusses design and qualification testing of the EDGs. Furthermore, compliance with the guidance of RG 1.9, Revision 2, does not apply to operational testing of installed, accepted EDGs. The title of RG 1.9, Revision 2, "Selection, Design, and Qualification of Diesel-Generator Units Used as Standby (Onsite) Electric Power System at Nuclear Power Plants" states that the guidance is for the design and procurement of EDGs. The introduction to RG 1.9, Revision 2, states, "This regulatory guide describes a method

' On September 22, 2008, NMC transferred its operating authority to NSPM, doing business as Xcel Energy. By letter dated September 3, 2008, NSPM assumed responsibility for actions and commitments previously submitted by NMC.

Page 3 of 7 NSPM acceptable to the NRC staff for complying with the Commission's requirements that diesel-generator units intended for use are onsite power sources in nuclear power plants be selected with sufficient capacity and be qualified for this service." Again, this points to the design and procurement of EDGs. RG 1.9, Revision 2, does not provide guidance for periodic testing of EDGs, but does refer to RG 1.I08 for periodic testing guidance. The PlNGP Unit 2 EDG design report did not commit to the testing guidance provided in RG 1.108, nor does the USAR reference RG 1.I

08.

In item 2 of the RAI background information provided above, the NRC cites the LAR NMC submitted on October 29, 2007 (Reference 3) as an example of compliance with RG 1.9. This is not an example of compliance, but rather an example where RG 1.9 has been used as a standard for comparison. The Enclosure in Reference 3, on page 6, explicitly states, "Although this LAR is consistent with the intent of RG 1.9 Revision 4 guidance for power factor test loading, this LAR does not commit to compliance with the provisions of RG 1.9, Revision 4."

In item 3 of the RAI background information provided above, the NRC cites the LAR NMC submitted on August 16, 2007 (Reference 4) as an example of compliance with RG 1.9. Again, this is not an example of compliance, but an example where RG 1.9 has been used as a standard for comparison. The Enclosure in Reference 4, on page 4, explicitly states, "Although this LAR is consistent with the RG 1.9, Revision 4, guidance for Unit 1 EDG monthly test loading, this LAR does not commit to compliance with the provisions of RG 1.9, Revision 4."

In item 4 of the RAI background information provided above, the NRC cites the LAR NMC submitted on November 21,2005 (Reference 5) as an example of compliance with RG 1.9. The context of this LAR is extension of the TS Completion Time: this does not relate to EDG testing requirements. The portion of this LAR quoted in item 4 above states that the proposed Completion Time "changes do not impact the capacity or margin of the emergency diesel generators". These are design features of the EDGs which are within the scope of commitment to RG 1.9 for the Unit 2 EDGs.

In item 5 of the RAI background information provided above, the NRC cites the LAR NSP submitted on March 20, 1992 (Reference 6) and the NRC safety evaluation for license amendments 103 and 96, Units 1 and 2, respectively, dated December 17, 1992 (Reference 7) as an example of compliance with RG 1.9. This is the license amendment which defined the testing requirements for the Unit 2 EDGs as follow up to the design report (Reference 2). As noted in the LAR to which these RAls apply, (Reference I),

reference to RG 1.9 is conspicuously absent in both the LAR discussion of the EDG test requirements and the NRC safety evaluation. The testing requirements appear to be consistent with the guidance that RG 1.9 provides in Section C Position 14, which modifies the order of events for testing given in IEEE Std 387-1 977. The guidance given in IEEE Std 387-1977 is for EDG type qualification testing and, per the IEEE guidance, is only required to be successfully completed once to satisfy the type qualification testing requirement. This guidance may have been the basis for the EDG Page 4 of 7 NSPM testing NSP proposed and NRC approved testing, but that does not make it a commitment to follow RG 1.9. The TS Bases provided in Reference 7 stated:

Each diesel generator can start and be ready to accept full load within 10 seconds, and will sequentially start and supply the power requirements for one complete set of safeguards equipment in approximately one minute (Reference 1 ).

An internal fault in the generator could damage the generator severely.

Moreover, this change complies with BTP ElCSB 17. Auto-connected loads should not exceed the overload rating of the diesel generator for the 2000 hour0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> maintenance interval, as prescribed in Regulatory Guide 1.9.

These paragraphs appear to be discussing EDG design features. RG 1.9 is not explicitly cited as the basis for the testing requirements.

2. On page 15 of 30 of the LAR, the licensee provides a discussion on why this proposed amendment "... does not involve a re-rate or de-rate..." of the D5 and D6 EDGs at PlNGP Unit 2. Provide an evaluation of the consequences of permanently de-rating EDGs D5 and D6 to comply with the testing requirement of RG 1.9, as well as enveloping the worst case accident load profile.

NSPM response:

NSPM does not propose to re-rate the Unit EDGs. With the TS changes proposed in Reference 1, NSPM committed to continue testing the Unit 2 EDGs, D5 and D6, at the current required power level at or above 90% of the load-carrying capability (51 00-5300 kW). Monthly testing will continue to test to this load level to obtain normal operating pressure and temperature data for trending of machine condition.

Engine rating is a vendor activity to assure that the appropriate engine is supplied to the customer to satisfactorily supply the applied loads. The D5 and D6 full-load continuous rating is 5400 kW which is the "factory advertised" load capability which is significantly higher than the design basis accident loads applied to these diesels. NSPM is not proposing to make physical changes to these engines associated with the proposed TS test load reduction and thus NSPM does not plan to pursue reduction of the Unit 2 EDG continuous load rating. NSPM has committed to continue testing the Unit 2 EDGs at their rated loading and thus, there no basis for de-rating these EDGs.

Page 5 of 7 NSPM

3. The discussion in the LAR indicates that the reliability of EDGs D5 and D6 has been impacted by the TS required load testing. Provide details for EDG target reliability assumed for compliance with 10 CFR 50.63 (Station Blackout Rule) and the reliability indicator for the last 20, 50, and 100 demands.

NSPM response:

As of June 4, 2009, the D5 and D6 reliability is shown in Table 1.

Table 1 Unit 2 Reliability Tracking (SWI SOE-2)

Review of Start and Load Run Demand Data 1

Valid DemandslFailures Allowable Failures (Trigger Values)

The valid failures associated with the D5 and D6 EDGs shown in Table 1 are not the result of "high load" operation at or near the EDG rated load. The following is a listing of the valid failures:

Last 100 Last 20 Actual Failures Trigger Values Exceeded - YesINo?

1.) D5 Room Exhaust Damper Failure (damper stuck closed due to binding linkage).

2.) D5 Fuel Rack Position processing circuit card (input to governor control) problem, thought to be loose wire. Issue turned out to be bad solder joint on card. See next event.

3.) D5 Fuel Rack Position processing circuit card (input to governor control) problem. This issue turned out to be caused by bad solder joint on card.

Last 50 3

The problem(s) of high load operation have been revealed through high crankcase pressure events. (Three high crankcase pressure events have caused Unit 2 shutdowns since 2001.) There have not been any high crankcase pressure events that have caused a 05 or D6 valid failure, but unavailability time is high because the crankcase pressure events that have occurred could only be repaired by cylinder liner replacement. High crankcase pressure events have also resulted in yearly inspections that cause additional unavailability time to be incurred.

1 No Throughout the LAR, "reliability" and "availability" are grouped together. The advantage to reducing the "acceptance criteria" for Unit 2 surveillance testing is to allow D5 or D6 to remain operable (for example, after proving that crankcase pressure is manageable at 4000 KW, or engine cooling remains acceptable following a heat exchange or cooling 4

Page 6 of 7 5

1 No 3

No NSPM fan issue) while planning for repairs. See the discussion provided above in the response to Question 2.

References

1.

NSPM letter to the NRC, "License Amendment Request (LAR) to Revise Emergency Diesel Generator (EDG) Test Loads in Surveillance Requirement (SR) 3.8.1.3 and SR 3.8.1.9", dated November 4, 2008, Accession Number ML083110125.

2.

NMC letter to the NRC, "Prairie Island Nuclear Generating Plant; Design Report for the Station BlackoutIElectrical Safeguards Upgrade Project", dated November 27, 1990.

3.

NMC letter to the NRC, "License Amendment Request (LAR) to Add a Power Factor to the Emergency Diesel Generators' (EDG) 24-hour Load Test (Surveillance Requirement 3.8.1.9)11, dated October 29, 2007, Accession Number ML073020289.

4.

NMC letter to the NRC, "License Amendment Request (LAR) to Increase the Unit 1 Emergency Diesel Generators' (EDG) Monthly Test Load", dated August 16, 2007, Accession Number ML072320401.

5.

NMC letter to the NRC, "License Amendment Request (LAR) For Extension Of Technical Specification (TS) 3.8.1, "AC Sources-Operating," Emergency Diesel Generator Completion Time", dated November 21, 2005, Accession Number ML053260088.

6.

NSP letter to the NRC, "License Amendment Request dated March 20, 1992, Auxiliary Electrical System Changes and Cooling Water System Changes".

7.

NRC letter to NSP, "Prairie Island Nuclear Generating Plant, Unit Nos. 1 and 2 Amendment Nos. 103 and 96 To Facility Operating License Nos. DPR-42 and DPR-60 (TAC Nos. M83070 and M83071)", dated December 17, 1992, Accession Number ML022240504 Page 7 of 7