U-603030, Application for Amend to License NPF-62,partially Reducing Load at Which DGs Are Required to Be Tested Per Affected SRs in Order to Reduce Stress & Wear on Machines While Still Sufficiently Challenging Machines to Confirm Operability

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Application for Amend to License NPF-62,partially Reducing Load at Which DGs Are Required to Be Tested Per Affected SRs in Order to Reduce Stress & Wear on Machines While Still Sufficiently Challenging Machines to Confirm Operability
ML20237C347
Person / Time
Site: Clinton Constellation icon.png
Issue date: 08/17/1998
From: Walter MacFarland
ILLINOIS POWER CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20237C349 List:
References
RTR-REGGD-01.009, RTR-REGGD-1.009 LS-98-003, LS-98-3, U-603030, NUDOCS 9808210105
Download: ML20237C347 (11)
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Text

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, Ilknois Power Cornpany Chnton Power Station P.O Box 678

% . Chnton IL 61727 Tel 217 935-5623 Fax 217 935-4632 Walter G. MacFarland IV Senior Vice President and Chief Nuclear Officer ILLINSIS P6WER u-603o3o An lilinova Cornpany .

8E.100a August 17, 1998 Docket No. 50-461 10CFR50.90 Document Control Desk Nuclear Regulatory Commission Washington, D.C. 20555

Subject:

Clinton Power Station Proposed Amendment of Facility Operating License No. NPF-62 (LS-98-003)

Dear Madam or Sir:

Pursuant to 10CFR50.90, Illinois Power (IP) hereby applies for amendment of-Facility Operating License No. NPF-62, Appendix A - Technical Specifications (TS) for Clinton Power Station (CPS). Per this request IP proposes to incorporate changes consistent with the recommendations of paragraphs 2.2.2,2.2.8,2.2.9, and 2.2.10 of Regulatory Guide (RG) 1.9, Revision 3, into Surveillance Requirement (SR) 3.8.1.3, SR 3.8.1.10, SR 3.8.1.14, and SR 3.8.1.15, respectively, with respect to testing of the l l standby emergency diesel generators (DGs). These changes partially reduce the load at j

which the diesel generators are required to be tested per the affected SRs in order to reduce stress and wear on the machines while still sufficiently challenging the machines to confirm operability.

The TS changes proposed in this application for amendment are desired for two MMM reasons. First, as mentioned previously, IP concurs that testing the diesel generators at reduced load levels reduces stress and wear on the machines. This can result in reduced .

maintenance and increased availability. Therefore, IP wishes to implement the guidance i- of RG 1.9, Revision 3, via appropriate changes to the TS, to reduce the load levels at i which the diesel generators are tested. (Note: At present, IP is not committed to RG i

1.9, Revision 3, per the current licensing basis for CPS. By this application for amendment, IP is adopting only that guidance in RG 1.9, Revision 3, that pertains to the SRs that are proposed to be revised. IP intends, at a later time, to perform a complete evaluation ofRG 1.9, Revision 3, for a more general incorporation of the Regulatory Guide into the CPS licensing basis.)

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U-603030 Page 2 l The second and more compelling reason for the proposed TS changes is due to the recent identification of a problem unique to SR 3.8.1.14. Per the current requirements of

' this SR, each DG is required to be operated and loaded to its continuous rating for at least j 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. For at least two hours during the 24-hour run, the DG must be loaded to a minimum of 110% ofits continuous rating. Recently, it was determined that after properly accounting for instrument accuracy, which required additional margin to be incorporated into the maximum and minimum load values specified in the test procedures, i the DGs can not be operated and loaded to greater than or equal to 110% of rated without exceeding the short-term ratings of the machines. Exceeding the short-term rating of a DG can cause damage, and depending on the degree and the length of time that the short-term rating is exceeded, can require significant inspection to be performed to assess any damage. This problem would be resolved by the proposed change to the Technical  ;

Specifications, since reducing the minimum required load would establish a load band within which each DG could be operated without the DG's short-term rating bemg i 1

exceeded.

A description of the proposed changes and associated justification (including a Basis for No Significant Hazards Consideration) are provided in Attachment 2. A marked-up copy of the affected pages from the current TS is provided in Attachment 3. A marked-up copy of the affected pages from the current TS Bases is provided in Attachment 4. Further, an affidavit supporting the facts set forth in this letter and its attachments is provided in Attachment 1. Following NRC approval of this request, IP will revise the CPS TS Bases in accordance with the TS Bases Control Program of TS 5.5.11, "TS Bases Control Program," to incorporate the changes identified in Attachment 4.

IP has reviewed the proposed changes against the criteria of 10CFR51.22 for categorical exclusion from environmentalimpact considerations. The proposed changes do not involve a significant hazards consideration, or significantly increase the amounts or change the types of effluents that may be released offsite, nor do they significantly increase individual or cumulative occupational radiation exposures. Based on the foregoing, IP concludes that the proposed changes meet the criteria given in 10CFR51.2(c)(9) for a categorical exclusion from the requirement for an Environmental Impact Statement.

With regard to when NRC approval of the proposed changes is needed, additional testing of the DGs per the affected SRs must be completed prior to restart from the current outage at CPS. Restart is scheduled to occur during the fourth quarter of this year. Consistent with this schedule and IP's desire to perform the applicable surveillance tests to the new criteria that would be established by the proposed changes to the TS SRs, IP respectfully requests NRC review and approval of the proposed changes as soon as possible.

Sincerely yours, hf A Waltec G. MacFarland, IV Senior Vice President and Chief Nuclear Officer i

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l' U-603030 Page 3

. TBE/mlh Attachments cc: NRC Clinton Licensing Project Manager NRC Resident Office, V-690 Regional Administrator, Region III, USNRC Illinois Department of Nuclear Safety 1

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Attachment 1 to U-603030 Page1of1 Wayne D. Romberg, being first duly sworn, deposes and says: That he is Manager-Nuclear Station Engineering Department; that this application for amendment of racility Operating License NPF-62 has been prepared under his supervision and direction; that be knows the contents thereof; and that to the best of his knowledge and belief said letter and the facts contained therein are true and correct.

Date: This O day of August 1998.

Signed: Y #

Wayne D. IVmberg STATE OF ILLINOIS ( SS.

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)L b __ COUNTY (

Subscribed and sworn to before me this day of August 1998.

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  • OFFICIAL SEAL ' L , )

l Notary PuWic, State of Illinois Joseph V. Sipek l C '

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ll My Commission Empiree 11/24/2001 ; i g (Notar[dblic) 7

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Attaciunent 2 to U-603030 LS-98-003 Page 1 of 7 Backdround Technical Specification (TS) 3.8.1 of the Clinton Power Station (CPS) Technical Specifications contains several Surveillance Requirements (SRs) that require the plant emergency / standby diesel generators (DGs) to be electrically loaded to a specific load (power level) for or during testing. The requirements of these SRs are consistent with Regulatory Guide (RG) 1.108, Revision 1. Specifically, SR 3.8.1.3 provides the requirements for the 60-minute load-run test, and requires the DGs to be loaded to greater than or equal to 100% of their continuous ratings. SR 3.8.1.10 provides the requirements for the full-load rejection test, and requires the DGs to be capable of rejecting a load i greater than or equal to 100% of their contimous ratings. SR 3.8.1.14 provides the .

l requirements for the endarance and margin test, and requires the DGs to be loaded to greater than or equal to 110% of their continuous ratings for at least two hours out of a j total 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of continuous operation, and to greater than 100% of their continuous ratings for the remaining portion of the 24-hour period (i.e., approximately 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br />). SR 3.8.1.15 demonstrates that the DGs can restart from a hot condition (such as when the DGs could be demanded to respond to an accident immediately following completion of normal surveillance testing) by verifying each DG starts and achieves required voltage and frequency within a specified time. This SR contains a Note that requires the SR to be performed within a specified time after the DGs have operated at a load greater than or ,

equal to 100% of their continuous ratings for at least one hour. l In July 1993, Revision 3 of RG 1.9 was issued. It integrates into a single Regulatory  !

Guide pertinent guidance previously addressed in RG 1.9, Revision 2; RG 1.108, Revision 1; and Generic Letter 84-15, " Proposed Staff Actions to Improve and Maintain Diesel Generator Reliability." RG 1.9, Revision 3 also endorses as appropriate the guidelines set  ;

forth in IEEE Standard 387-1984, "IEEE Standard Criteria for Diesel Generator Units

' Applied as Standby Power Supplies for Nuclear Power Generating Stations."

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In particular, RG 1.9, Revision 3 contains modified acceptance criteria for tests involving loading of the DGs. Specifically, paragraph 2.2.2 ofRG 1.9, Revision 3 addresses the 60-minute load-run test and recommends loading the DG to 90% to 100% ofits continuous rating (vice greater than or equal to 100% ofits continuous rating). Paragraph 2.2.8 of RG 1.9, Revision 3 addresses the full-load rejection test and recommends verifying that the DG is capable of rejecting a load equal to 90% to 100% ofits continuous rating (vice greater than or equal to 100% ofits continuous rating). Paragraph 2.2.9 addresses the

- endurance and margin test (i.e., 24-hour run test) and recommends loading the DG to 105% to 110% (vice greater than or equal to 110%) ofits continuous rating for at least two hours, and to 90% to 100% (vice greater than 100%) ofits continuous ratings for the remaining portion of the 24-hour run. Paragraph 2.2.10 addresses the hot restart test, and recommends the test be conducted after a DG has been operated for two hours at full load.

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Attachment 2 to U-603030 LS-98-003

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Page 2 of 7 Description of Proriosed Changes in accordance with 10CFR50.90, IP proposes to change TS 3.8.1 by revising the acceptance criteria of SR 3.8.1.3, SR 3.8.1.10, and SR 3.8.1.14 to be consistent with the recommendations of RG 1.9, Revision 3, paugraphs 2.2.2, 2.2.8, and 2.2.9, respectively.

Additionally, IP proposes to revise Note 1 of SR 3.8.1.15 to be consistent with the recommendation ofparagraph 2.2.10 of RG 1.9, Revision 3.

The proposed changes are consistent with RG 1.9, Rev, 3, since they involve adopting the reduced load levels recommended by the Regulatory Guide. However, in lieu of specifying a band for the reduced load levels, as prescribed or implied in the Regulatory Guide, only minimum values corresponding to the minimum values specified by the Regulatory Guide are proposed to be specified in the Technical Specifications. Thus, for example, in lieu of specifying the required load leveh for the 60-minute load-run test as 290% and <100% of the diesel generator's continuous rating (per Section 2.2.2 of the Regulatory Guide, which states to perform the test at "90 to 100 percent of the continuous rating of the emergency diesel generator"), Technical Specification SR 3.8.1.3 would be revised to simply require performance of the test at 290% of the diesel generator's continuous rating. The basis for the approach is explained later in the

" Justification for Proposed Changes" section of this submittal.

The specific cl.anges to each of the SRs are described below. To simplify and facilitate the description of the requirements and proposed revisions, the values for the various DG loadings in units of kilowatts (kW) versus percent (%) of each DG's continuous rating are provided in the table below:

Diesel Continuous Rating 90% of Continuous 105% of Continuous 110% of Continuous Generator (kW) Rating (kW) Rating (kW) Rating (kW)

DG1A 3869 3482 4062 4256 DGIB 3875 3488 4069 4263 DGIC 2200 1980 2310 2420 SR 3.8.1.3 currently requires each DG to be operated for at least 60 minutes at a load 2100% ofits continuous rating. SR 3.8.1.3 is being revised to instead require each DG to be operated at a load 2 90% ofits continuous rating. (Refer to the table above and to the marked-up, affected page from the Technical Specifications, in Attachment 3, for the corresponding power / load values expressed in units of kW for each DG.) j SR 3.8.1.10 currently requires verifying that each DG does not trip and that voltage is maintained above a specified value following rejection of a load 2100% ofits continuous rating. SR 3.8.1.10 is being revised to instead require each DG to be capable of rejecting a load 2 90% ofits continuous rating. (Refer to the table above and to the marked-up,

. affected page from the Technical Specifications, in Attachment 3, for the corresponding power / load values expressed in units of kW for each DG.)

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Attachment 2 to U-603030 LS-98-003 Page 3 of 7 SR 3.8.1.14 requires each DG to be continuously operated at a specified power factor for at least 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. It currently requires each DG to be loaded to 2110% of the continuous rated load for at least 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />, and loaded to 2100% of the continuous rated load for the remaining hours. SR 3.8.1.14 is being revised to instead require each DG to be loaded to 2105% ofits continuous rating for at least 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />, and to 2 90% ofits continuous rating for the remaining time. (Refer to the table above and to the marked-up, affected page from the Technical Specifications, in Attachment 3, for the corresponding power / load values expressed in units of kW for each DG.)

s Note 1 of SR 3.8.1,15 currently requires the surveillance to be performed within 5 minutes of shutting down the DG after it has operated 21 hour2.430556e-4 days <br />0.00583 hours <br />3.472222e-5 weeks <br />7.9905e-6 months <br /> at a load 2100% ofits continuous rating. This Note is being revised to require the surveillance to be performed within 5 minutes of shutting down the DG after the DG has operated for 2 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> at a load 2 90%

and ofits continuous rating. (Refer to the table above and to the marked-up, affected page

- from the Technical Specifications, in Attachment 3, for the corresponding power / load

. values expressed in units of kW for each DG.)

Corresponding changes proposed for the associated TS Bases are provided for information in Attachment 4. As the Bases are not formally part of the Technical Specifications, the proposed changes to the Bases will be separately processed by IP per the Technical Specification Bases Control Program, as described in Technical Specification 5.5.11.

Justification for Proposed Channes The 60-minute run test (SR 3.8.1.3), the full-load reject test (SR 3.8.1.10), and the 24-hour run test (SR 3.8.1.14) are currently required to be conducted at loads greater than or equal to the cor"inuous ratings of the DGs Except for a required portion of SR 3.8.1.14 I (as described below), these tests are being revised to allow them to be conducted with the i DGs loaded >90% of their continuous ratings, consistent with the guidance ofRG 1.9, Revision 3. These changes are necessary for the Technical Specifications to permit testing of the DGs to be performed at reduced load levels, thus reducing stress and wear on the machines, while still ensuring that the DGs are adequately challenged at operating i temperatures to connrm operability.

As noted previously, Rev. 3 of RG 1.9 prescribes or implies in Sections 2.2.2, 2.2.8, and i 2.2.9 that the DGs are to be loaded to a load level of 90 to 100 percent of their continuous l

[ ratings for the performance of the corresponding testwxcluding the 2-hour portion of the 24-hour DG endurance test). However, for the associated proposed changes to the Technical Specifications, IP is proposing only to require that the DGs be loaded to a load i h level greater than or equal to 90 percent of their continuous rating, with no upper limit i specified. This is based on the following reasons / considerations:

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Attachment 2 l to U-603030 LS-98 003 Page 4 of 7  !!

- (1) ' The intent of the recommended guidance in Rev. 3 of RG 1.9 for these tests is to reduce the load levels at which the DGs are routinely tested, while still ensuring that the DGs are sufficiently challenged to verify their operability. Reducing the -

minimum required load level meets this intent without the need to specify an upper limit.

(2) Licensees (DG owners) are motivated not to test or operate the DGs at excessive load levels for both economic and safety reasons, including reducing stress and wear on the machines. Further, DG manufacturers typically specify ratings or load levels for DGs which, if exceeded for certain periods of time, can require the DGs to undergo additional inspections or maintenance. For these reasons, testing is typically performed as close to the minimum required level as possible. l (3) The format of the proposed Technical Specification changes (i.e., with no maximum limit specified)is consistent with the format of the current Technical Specifications, wherein no maximum limit is specified. In addition, specifying an upper limit in the Technical Specifications could require a surveillance to be considered a failure or invalid if the upper limit is even slightly exceeded, even though the intent of the surveillance may have been met.

On this basis, the proposed changes to the above-noted SRs incorporate reduced minimum load levels for testing, consistent with the intent of Rev. 3 of RG 1.9.

With further regard to the 24-hour run test (SR 3.8.1.14), this test currently requires each DG to be operated at a load greater than or equal to 110% of the DG's continuous rating for a minimum of two hours. This test is being revised to allow each DG to be operated instead at a load of greater than or equal to 105% of the DG's continuous rating for two hours. Testing of the DGs at the proposed minimum load level is consistent with the guidance of Rev. 3 of RG 1.9, and would continue to provide assurance that some margin exists above the continuous ratings of the DGs.

At the same time, as noted in the cover letter, reducing the minimum required load level provides more operating margin to avoid exceeding the short-term rating for each machine during testing. Taking instrument accuracy into account (e.g., for the power meters used to indicate and note load levels during testing) requires additional margin to be included in the load limits specified in the associated test procedures. This results in increased minimum limits and decreased maximum limits being specified in the associated test procedures. In fact, reducing the minimum load level specified in the procedures to a value based on 105% of each DG's continuous rating is necessary to avoid exceeding the l

short-term rating specified as the maximum limit in the test procedures.

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! For the same reasons described above, IP also proposes to specify only a minimum load level for the 2-hour portion of the endurance test required per SR 3.8.1.14. The higher load level at which each DG is required to operate for this portion of the endurance test makes it especially unnecessary to specify a maximum limit due to the increased incentive

I Attachment 2 I to U-603030 LS-98-003 ,

Page 5 of 7 I to avoid exceeding short-term ratings of the DGs that could trigger additional maintenance or inspections. Further, when instmment inaccuracies are taken into account in establishing the minimum and maximum load limits to be spccified in the associated test procedures, the band within which the diesel generator load must be controlled would be difficult to achieve or maintain if SR 3.8.1.14 specified a band of 105% to 110% of each DG's continuous rating. That is, a band of 5% is too narrow if margin due to instrument { ^

accuracy must be added to the minimum limit and subtracted from the maximum limit.

With regard to the requirements of SR 3.8.1.15, associated Note 1 sets forth conditions under which the SR must be performed. That is, the intent of Note 1 is to ensure that the SR is performed with the diesel sufficiently hot Under the current SR, this is achieved by running the diesel for at least one hour at a load level 2100% ofits continuous rating.

This condition may be achieved, for example, by performance of another SR, such as SR - 3.3.1.14, immediately preceding SR 3.8.1.15.

Consistent with the changes proposed for the other affected SRs, the DG load level specified within Note 1 is being reduced to allow SR 3.8.1.15 to be performed following a loading that is less than what is currently required. That is, in keeping with the intent to allow SR 3.8.1.15 to be performed following performance of other SRs, it is consistent to reduce the required load level specified in Note 1 if the required load levelis being reduced in those other SRs. However, whereas the current version of Note 1 requires the DG to be previously loaded to the required load level for greater than or equal to one hour for performance of SR 3.8.1.15, the proposed version of Note 1 would require the DG to be previously loaded to the new, reduced load level for at least two hours for performance of SR 3.8.1.15. The required load period of two hours is consistent with the guidance of RG 1.9, Revision 3.  ;

Based on the above, IP concludes that the proposed changes to SR 3.8.1.3, SR 3.8.1.10, SR 3.8.1.14, and SR 3.8.1.15 have no adverse impact on safety.

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Basis for No Significant Hazards Consideration In accordance with 10CFR50.92, a proposed change to the operating license involves no )

significant hazards consideration if operation of the facility in accordance with the j proposed change would not: (1) involve a significant increase in the probability or i consequences of any accident previously evaluated, (2) create the possibility of a new or different kind of accident from any accident previously evaluated, or (3) involve a j significant reduction in a margin of safety. This request is evaluated against each of these j criteria below.

1 i f (1) Analyzed events (or events bounded by analyzed events) are initiated by the failure of certain plant structures, systems or components. The scope of the proposed I changes is limited only to the revision of several Surveillance Requirements (SRs) for testing of the standby emergency diesel generators (DGs). The DGs are not L _ _. . _ _ _ _ _ - _ . ._ _ _ _ _ _ . -- _. __ . _ _ . _ - _ _ - _ _ _- _ _ _ _ L

Attachment 2 to U403030 LS-98-003 Page 6 of 7 considered as initiators of any analyzed event. Thus, the proposed changes do not impact the probability of any accident previously evaluated.

The consequences of analyzed events are dependent on the successful functioning of credited equipment to mitigate such events. With respect to the proposed changes, there is no impact on the capability of credited equipment, i e., the diesel generators, to perform as required (is the event of a loss of coolant accident concurrent with a las of offsite power). Testing at reduced load levels reduces 1 stress and wear on the diesel generators, while still ensuring that the DGs are f adequately challenged at operating temperatures to confirm operability. In addition, reducing the minimum required load levels reduces time when, or the probability that, the short-term rating of any diesel generators is exceeded during 2 testing. The resultant reduction in stress and wear increases DG availability.

Based on the abeve, IP has concluded tret the proposed changes will not result in 1 a significant increase in the probability or consequences of any accident previously l evaluated. l (2) The proposed changes do not involve a physical alteration of the plant. No new or different equipment is being installed, and no installed equipment is being operated in a new or different manner. There is no alteration to the parameters within which the plant is normally operated or in the set points that initiate protective or mitigative actions. As a result, no new failure modes are being introduced.

Based on the above, IP has concluded that the proposed changes will not create the possibility of a new or diff9 tent kind of accident not previously evaluated.

(3) The revised Surveillance Requirements are consistent with the recommendations of RG 1.9fRevision 3. Testing at reduced load levels reduces stress and wear on the ,

diesel generators, while still ensuring that the DGs are adequately challenged at l operating temperatures to conCrm operability. In addition, reducing the minimum  !

required load levels reduces time when, or the probability that, the short-term )

rating of any diesel generators is exceeded during testing. The resultant reduction  ;

in stress and wear increases DG availabdity. l Margins of safety are established through the design of plant stmetures, systems and components, the parameters within which the plant is operated, and the establishment of set points for the actuation of equipment relied upon to respond to an event. With respect to any margins of safety associated with the diesel i generators, the proposed changes do not impact diesel generator perfonnanca, and involve no changes to ar.y setpoints or settings associated with the diesel generators, nor do the proposed changes involve any changes to any assumptions i

of the plant safety analyses with regard to the function of the diesel generators.

Thus, no margins of safety are impaced by the proposed changes.

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Attachment 2 l to U-603030 ]

LS-98-003 .1 Page 7 of 7 Based on the above, IP has concluded that the preposed changes will not result in a reduction in a margin of safety.

Based on the foregoing, IP concludes that the proposed changes do not involve significant hyards consideration.

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