1CAN079902, Documents ANO-1 Position Discussed on 990705,with Members of NRC Staff & Formally Requests Enforcement Discretion from Requirements of TS 3.7.2.C to Allow Continued Power of Operation
| ML20209C700 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 07/06/1999 |
| From: | Vandergrift J ENTERGY OPERATIONS, INC. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 1CAN079902, 1CAN79902, NUDOCS 9907120183 | |
| Download: ML20209C700 (14) | |
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- July 6,-1999 1CAN079902 U. S. Nuclear Regulatory Commission Document Control Desk
' Mail Station OPI-17
- Washington, DC 20555
Subject:
Arkansas Nuclear One -Unit 1 Docket No. 50-313 License No. DPJt/1
- Request For Enfo.c. snent Discretion Gentlemen:
This letter documents the Arkansas Nuclear One, Unit-1 (ANO-1) position discussed on July'5, 1999, with members of the Nuclear Regulatory Commission staff and formally requests enforcement discretion from the requirements of Technical Specification (TS).3.7.2.C to allow continued power operation of ANO-1 with one Emergency Diesel Generator (EDG) inoperable for a period beyond the current allowable outage time (AOT). EDG-#2.was removed from service for scheduled maintenance at 2237 CDT on June 28,1999. During post-maintenance testing, it was determined that work performed to correct an observed degrading lubricating oil '
pressure trend was unsuccessful., The EDG was shutdown as a result of abnormally degraded oil pressure. Correction of this condition and restoration of operability are anticipated to_ extend
. beyond the expiration of the allowable outage time. Due to the current esthate of the duration of /
the remaining activities to restore operability, an extension of seven days '.o the existing allowable outage time is being requested, j-The enclosed request was reviewed and approved by tim ANO Plant Safety Committee at'-
approximately 1700 CDT on July 4,1999. Verbal approval of this enforcement discretion request ;
was granted at opproximately 0950 CDT on July 5,1999. This' discretion will be in effect until
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- ANO-1 EDG #,1 is restored to an operable condition or 2237 CDT on July 12,1999, whichever -
occurs first. If significant problems occur during the remaining maintenance and testing activities
' that indicate 'that the causee of thelfailure has not been corrected ~ and . that additional troubleshooting is required, ANO willinitiate further communications with the NRC.-
IV ' rulyburs,
.T D. Vander Director, Nuclear Saf 9907120183 990706 ,
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U. S. NRC July 6,1999 . .
1CAN079902 Page 2 cc: Mr. Ellis W. Merschoff Regional Administrator U. S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-8064 NRC Senior Resident Inspector Arkansas Nuclear One P.O. Box 310 London, AR 72847 Mr. NickIElton NRR Project Manager Region IV/ANO-1 U. S. NuclearRegulatory Commission NRR Mail Stop 13-D-18 One White Flint North 11555 Rockville Pike Rockville, MD 20852 dm
i .
Enclosure to ICAN079902 Page1 of12 REQUEST FOR ENFORCEMENT DISCRETION REGARDING AN INOPERABLE EMERGENCY DIESEL GENERATOR Backaround Infor nation ANO-1 is equipped with two seismically qualified, class IE, diesel engine driven generators which -
supply emergency electrical power to the 4160 volt (V) vital AC busses. Each engine is designed to automatically rtart and tie-on to its respective 4160V engineered safety features (ESF) bus in the event of a bus under-voltage condition on either the 41CV bus or its associated 480V_ load -
center. The EDGs also receive an auto start command on an ESF signal, but will not load unless a bus under-voltage condition exists.
Each EDG is designed to start automatically upon receipt of a start demand, attain rated speed and voltage within 15 seconds, and sequentially accept ESF loads. Each ANO-1 EDG is sized to accommodate loads up to all anticipated ESF actuated equipment with a continuous load rating of 2600 kilowatts (kW) and an intended service rating of 2750 kW.
The EDGs are designed for manual operation from either the local control panel or the control room operating panel. This provision allows operation for surveillance testing and manual start and load operations as well as local operations in an event that renders the control rooin inaccessible.
The EDGs are described in chapter 8.3.1.1.7 of the ANO-1 Safety Analysis Report.
An 18-month inspection of the ANO-1 EDG #1 was recently completed. The post-maintenance testing during the week of June 21,1999, consisted of satisfactory completion of an engine start at slow idle, over-speed trip test, and operability run. Based upon a sliding 12-month average, availability ofEDG #1 has been 99%.
In addition to the EDGE, ANO has installed a diesel generator pursuant to the requirements of 10CFR50.63, Loss of All Alternating Current Power, paragraph (c)(2), Alternato AC Source.
The Alternate AC Diesel Generator (AACDG) is a 16 cylinder, four stroke, turbocharged, diesel -
engine driven generator rated at 4400 kW continuous output and 5320 kW ' overload. Its size is based on the capability to supply the licensing basis loss of offsite power (LOOP) loads of any one of the four vital buses. The AACDG is captble of supplying 4160V power to AMO-1 vital buses A3 or A4 or ANO-2 vital buses 2A3 or 2A4. It can also supply non-vital 4160V buses _Al for -
ANO-1 or 2Al in ANO-2. The buses can be supplied in any combination as long as the total load does not exceed the engine load rating. The design consideration for the AACDG assumed the engine would be started from the control room and available to power the safety buses within 10 minutes of the' diagnosis of a station blackout condition. The 10 ' minute criterion is a bounding value from section; 3.2.5 of NRC Regulatory Guide 1.155,- Station Blackout,"E and 10CFR50.63(c)(2) that, it demonstrated, precludes the necessity for performing a specific coping analysis. The' AACDG output was tied to an ANO-1 vital bus (A3) during startup program testing on March 22,1995, and to an ANO-2 vital bus on October 11,1995. These tests loaded
Enclosure to ICAN079902
~ Page 2 of12 the engine and measured voltage dip. During these tests, an actual blackout event was simulated and the time to energize the buses was recorded. In each case the time was less than the 10-minute criterion.
The AACDG is completely independent from off-site power and the EDGs. The AACDG, all support systems, and attendant electrical buses are housed in a dedicated building located outside the power block, inside the protected area fence. The AACDG is discussed in section 8.3.1.1.3 and 8.1.4 of the ANO-1 Safety Analysis Report (SAR) that refer to section 8.3.3 of the ANO-2 SAR for details.
The AACDG is a non-Q, manually started and loaded alternate source of AC power. Operation and loading of the AACDG is possible from the Unit 2 Control Room or locally. All operations involving the AACDG are directed by procedure 2104.037. This procedure contains instructions for operating under various circumstances such as starting, loading, tinloading, aligning to electrical buses, emergency starting / loading, and starting / loading with failure of both controlling computers. The procedure also contains instructions for the quarterly full load test and an 18--
month test that verifies starting and loading in less than 10 minutes.
The AACDG system unavailability is monitored. It is a risk-significant Maintenance Rule system that is well within the unavailability performance criterion. Availability over the previous 12 months has been greater than 95%.
Techairal Snecification (TS) Reauirine Enforcement Discretion Arkansas Nuclear One - Unit 1 (ANO-1) TS 3.7.2.C states that either one of the two Emergency Diesel Generators (EDGs) may be inoperable for up to seven days in any morith provided that during such seven days the operability of the other EDG is demonstrated inunediately and daily thereafter, it also requires that there are no inoperable Engineered Safety Features (ESF) components associated with the operable EDG and that two sources of off site power are available. The allowable outage time will be exceeded prior to completion of engine repair and testing. The other TS requirements related to the inoperable EDG condition will continue to be satisfied.
Circ ====*= nema Surroundlas Situation / Annarent Ret Cause / Need For Promnt Action /
Relevant HistoricalInformation HistaCv The ANO-1 EDG #2 has had a decreasing tube oil header pressure trend over approximately the past four years. From July 1995 to' January 1998, the trend was very slight (from approximately 82 to 72 psi). The pressure decreased further until April 1998, while refueling outage IR14 was in progress, when it stabilized at approximately 55 psi. Subsequent surveillances showed a slight
l Enclosure to ICAN079902 Page 3 of12 trend of approximately one psi difference each month. In May 1998, the EDG vendor was contacted for assistance in determining possible causes and troubleshooting methodology. Four primary possible causes were identified: lube oil suction air in-leakage, malfunctioning relief valve, degraded lube oil pump, and deteriorated bearings. After additional pressure degradation was noted,- ANO-1 System Engineering established a pressure threshold of 40 psi that would trigger additional actions. This value was based on wintaining margin to the minimum operating pressure. In preparation for the June 28, 1999 EDG maintenance, the vendor was contacted zgain, and plans were made to investigate the cause of the decreasing tube oil pressure. The vendor indicated that this type of oil pressure degradation has been seen in oener engines and had been attributed to either the lube oil pump suction piping ledng or the header relief valve set point drifting. Neither condition was considered detrimental to engine operation.
At 2237 CDT on June 28,1999, #2 EDG was removed frcm service for scheduled maintenance.
Prior to removing EDG #2 from service, EDG #1 was satisfactorily started and loaded. During the EDG outage, the lube oil header relief valve was replaced. The oil pump suction piping was disassembled and seals replaced. The lube oil pump, main bearings, scavenging oil system, and various gaskets were inspected. Also, the clearance was checked on #1 idler gear bushing. With the exception of a possible leak on a pump suction gasket, no abnormal conditions were noted.
Following the maimenance, EDG testing indicated that the lube oil pressure had improved. The starting oil pressure prior to maintenance was approximately 50 psi. After the relief valve replacement starting oil pressure was approximately 80 psi. However, on July 1,1999, after operation at full load for approximately one hour as part of the post-maintenance testing, the EDO was shut down when lubricating oil pressure degraded to approximately 33 psi. The low oil pressure alarm setpoir.1 is 26 psi and the engine trip setpoint is 17 psi. The vendor technical manual documents that engine performance should not be affected unless the engine is operated with leu than 25 psi lube oil pressure at full speed.
Inmection After the engine was shut down, the EDG vendor representative recalled a difference in the flow of oil from the generator gear train on EDG #2 when compared to observations in the same area on EDG #1 in the same configuration during its 18-month engine inspection in June,1999.
Although oil flow from this area is normal, the increased oil flow prompted the vendor to inspect the engine lube oil sump for debris. A magnetic rod was used to recover portions of two failed fasteners. These two bolt heads, attached with safety wire, were located in the viciruty of the gear train retum opening.
Diagnostic work included the testing of the relief valve removed during the engine outage. Bench testing indicated that the valve lift setting had drifted to a value significantly below its setpoint. ,
During dirassembly of EDG #2, the two bolts holding the idler gear stubshaft bracket to the engine around_ the #1 idler gear were found to have failed. . The remaining bolts were loose. All bolting around the #1 idler gear exhibited signs of failure. The bracket had a crack that propagated over 80% of the cross-section between the #1 and #2 idler gears. Comparing the bok
w Enclosure to ICAN079902 Page 4 of12 failure points and fracture surfaces, it appeared that the failures were fatigue related. One bolt had failed at the head fillet, the intersection between the head and shank and had an obvious crack within 3/8" of bolt tip. Another bolt had failed at thread run-out, between the bolt shank and the first few threads. The remaining three bolts failed near the area where there is thread engagement between the bolt and engine hole threads, within 3/8" of the bolt tip. All of thea locations are common failure points in bolting. Four of the five failures appear to have been caused by fatigue.
The failure of the remaining bolt (between shank and threads) appears to have been sudden based on the fracture surface appearance. This was one of the two bcit heads recovered by the vendor.
Abnormal wear patterns were noted on all the gearing. The #1 idler gear and the main gear showed the greatest signs of wear. This can be attributed to the loss of support of the #1 idler gear. The #2 idler gear and north bank cam gear also showed signs of abnormal, but less severe, wear. The south bank cam gear showed the least amount of wear, as expected, since it is the last gear in the train.
AssemblyDetails The idler stub shaft assembly is bolted over the end of the oil galley. Oil is circulated to the generator end gearing and directed to the camshafts through posts on the underside of the stub shaft assembly and camshaft bearing plates. . Jumpers are installed to direct oil to these separate -
components. The #1 idler gear shaft is cantilevered from the stub shaft plate. The #2 idler gear is fixed to the stub shaft plate and gains additional support from the turbocharger housing. It is believed that the bolting initially failed on the steb shaft assembly in the location of the #1 idler gear. It is postulated that one fastener initially failed. This allowed the clearances between the stub shaft assembly and the engine to increase. There is no seal between these components.
Therefore, oil is allowed to flow from behind the plate directly to the sump.
Apoarent Cause Discussion I
I Initial oil pressure degradation is believed to have been caused by drifting of the relief valve set point. It is feasible to consider that the relief valve affected lube oil pressure over time. ;
During refueling outage IR14 testing in early 1998, the initial fastener is believed to have failed due to fatigue. This would account for a step change in oil pressure as a result of clearances increasing between the stub shaft assembly and the engine frame. The remaining bolting accepted the load released by the failed fastener.
Oil pressure continued to degrade slowly as a result of the suspected relief valve set point drift.
The pressure degradation was slow and similar to earlier trends.
During the engine maintenance started on June 28,1999, installing a new relief valve increased engine header pressure above previous values. It is believed that this increased the stress on the bolting material because of the added hydraulic pressure from the relief valve and the added surface area as a result of the initial fastener failure.
Enclosure to ICAN079902 Page 5 of12 During post-maintenance testing, the remaining bolting may have failed as a result of the higher stress induced from the combined effects. This accounts for the improved oil pressure performance with the subsequent downward step change. Since four of the five fasteners showed indication of fatigue failure, it is postulated that their failure caused the failure of the remaining fastener due to overload.
As a result of the fastener failures, the #1 idler gear was restrained by the #2 idler gear and the fasteners associated with the upper portion of the stub shaft assembly. The #2 idler gear shaft is structurally supported from two places. The resulting structure is very stiffin the upper portion of the stub shaft assembly with the lower stub shaft plate absorbing the torsionalload imparted from the main gear to the #1 idler gear. With the failure of the fasteners, load would be transmitted to the upper portion of the stub shaft assembly. The failure of multiple fasteners would allow significant movement of the lower portion of the stub shaft plate. The movement would be cyclic based on the mesh of the gear teeth and the flexural strength of the material. The overloaded condition over the short duration would have induced high stress fatigue in the plate.
The apparent cause of failure is considered to be the fatigue failure of the bolting material.
Corrective Actions To address the condition of the fatigued bolts, the cracked idler stub-shaft bracket assembly, and the worn gearing, the following corrective actions are being implemented:
- A new modified idler stub-shaft bracket assembly with improved bolting and oil flow channels is being installed. Three new bolts are added in the top of the bracket and the four bolts in the
- 1 idler stub-shaft have been increased in size from %" x 1 %" to 5/s" x 6 %". The longer bolts will extend into the engine block to provide additional clamping espability. This change is in accordance with vendor recommendation.
- The gear train is being replaced. This includes the crankshaft gear, #1 idler gear, #2 idler gear, spring gear assembly, right and left camshaft gears.
- Replace lube oil filters and inspect strainers.
- Inspect main lube oil pump.
- Inspect main lube oil pump suction piping.
Based on the normal value of EDG #1 lube oil pressure and normally expected variation between engines of this design, ANO haa determined that a post-maintenance EDG #2 lube oil pressure !
stable above 60 psi will be considered an indication that the repairs have been effective and that 1
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the engine is fully operable. Further troubleshooting will be initiated if pressure is below 60 psi during post-maintenance testing.
GenericImolications for EDG H1 EDG #1 has not demonstrated the same symptoms oflube oil degradation exhibited by EDG #2.
The EDG #1 idler gear stub-shaft assembly, bolts, and gears were replaced with the modified design in December 1984. Therefore, the failure mechanism demonstrated by EDG #2 has been determined not to be a cornmon cause failure.
Safety Basis For The Reauest In letter 0CAN059603 dated May 2,1996, ANO submitted a Technical Specification Change request to extend the AOT for both Unit's EDGs to 14 days. While the request was subsequently withdrawn because of the schedule for implementation of ANO's Risk Management Program (RMP), the technical basis providing justification for that change remains valid.
The Risk Management Program at ANO-1 is currently under development and pastially implemented. Although the programmatic procedures, desk guides, and links required to make the Equipment Out of Service (EOOS) model a "real time" system have not been fully established, the EOOS program has been developed for ANO-1. Currently the EOOS model is being utilized daily by the Planning & Scheduling Liaison to evaluate the risk associated with maintenance activities. In addition to the performance of a quantitative assessment performed by EOOS, a qualitative assessment is performed daily by the Planning & Scheduling Liaison. This qualitative assessment covers a broad range of areas including, for example, trip or transient potential, reactivity mismanagement potential, redundant equipment availability, cross unit impact, red train
- green train separation, and severe weather contingencies.
The technical basis for the TS change request in OCAN059603, CE NPSD-996, identified thit the least amount of risk was associated with allowing the unit to make repairs of short duration identified while still at power, as opposed to shutting down for the repairs. If the plant is required to shutdown while the EDG is out of service, the constant risk to core damage associated with the EDG out of service is expected to increase due to challenges that will be placed on components and personnel to effect a shutdown. ' This change in conditions is considered a " transition risk."
The transition risk is additional risk due to challenging the transfer of electrical loads from their normal power supplies (unit auxiliary transformer fed from the main generator) to an alternate source of power. Should a problem occur with the transfer of electrical loads to off-site supplies, this would result in an increase in risk above what is normally expected given the unavailability of an alternate power source. Using the met! >f CE NPSD-996 and correlating those results to
- ANO-1, the transition risk is expected to be greater than that of a seven day extension of power operation.
Enclosure to ICAN079902 Page 7 of12 A dominant concern associated with a shutdown would also be that of feedwater to the steam generators. While at power, a heat removal system is established using main feedwater, the main turbine, and condenser. Shutting down the unit will remove this success path and place the plant in a condition where AC power becomes more critical in providing decay heat removal from the core. By remaining at power, additional success paths such as main feedwater are available.
.In addition to the assessments provided in CE NPSD-996, an assessment of the change in the ANO-1 core damage frequency (CDF) due to allowing ANO-1 to continue at power operation while repairing EDG #2 beyond the TS AOT of 7 days was performed A summary of the results of this risk assessment follows.
Using the ANO-1 Equipment Out Of Service (EOOS) PSA model, the CDF associated with two at power plant conditions was assessed:
Case 1: No plant equipment Out of Service (OOS) and Case 2: EDG #2 OOS.
The results of these EOOS calculations are summarized in Table 1 below:
Table 1.
Case 1. Baseline 2.29E-05 Case 2. EDG #2 OOS 4.69E45 _
Change in CDF 2.40E-5 Using these results, the estimated change in the annual and the cycle average ANO-1 CDF for an additional 7 days of power operation while EDG #2 is OOS is provided in Table 2.
Table 2.
Extension of Annual Annual NRC CDF EPRI CDF EDG #2 OOS Time Average Average Risk Region Risk Region Beyond 7 day AOT ACDF %ACDF
(/rx-yr) (/rx-yr) 7 days 4.6E-07 2.0% III NRS As noted in the table, the change in the annual average ANO-1 CDF associated with allowing a one time extension of the EDG #2 OOS time beyond its current 7 day AOT is in Region III (very small risk) of the NRC's CDF acceptance guidelines in Figure 3 of Reg. Guide 1.174. The 4.6E-7/rx-yr change in CDF is well below the Region II threshold of IE-6/rx-yr. In addition, the change is also corddered Not Risk Significant (NRS) per the EPRI CDF Quantitative screening criteria in Table 4-1 c'the EPRI PSA ' Applications. Guide. The 2.0% change in CDF is well-below the "Further Evaluation Required" threshold of 21% for the ANO-1 baseline CDF of 2.29E-5/rx-yr. {
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Enclosure to 1CAN079902 Page 8 of12 It is noted that the ANO-1 EOOS' modelis an " internal' events" model and does not account for
" external events" such as seismic events, internal fires, floods, high winds and tornadoes, as well as transportation and nearby facilities accidents. A vulnerability review of these risk contributors was performed during the ANO-1 IPEEE process. Although the ANO-1 IPEEE analyses did not .
produce a quantitative estimate of the external events contribution to the ANO-1 CDF, these reviews concluded that ANO-1 has a relatively low risk from external events. Since the internal events CDF is well within the NRC Reg. Guide 1.174, Figure 3, Region III and within the EPRI "Not Risk Significant" regions and since the external events CDF contribution was determined to be relatively low, it is concluded that the overall change in the CDF due to the additional 7 days of power operation while the EDG #2 is OOS does not contribute significantly to the ANO-1 CDF.
The ANO-1 EOOS model is a Level-1 (i.e., CDF) model and does not calculate the ANO-1 Large Early Release Frequency (LERF). The ANO-1 IPE analysis estimated that the large release
. accident scenarios account for less than 3% of the total CDF. It is judged that the effect of increasing the EDG #2 OOS time on LERF is proportional to the increase of CDF Using this judgment, the increase in LERF is also within Region III and in the EPRI "Not Risk Significant" region for LERF.
Although increasing the EDG #2 OOS time for an additional 7 days slightly increases at-power risk, shutting the plant down to do repairs on EDG #2 also increases risk and is expected to be -
greater than that of a seven day extension of power operation. A review of the ANO-1 dominant failure sequences identified similar concerns to CE NPSD-996. Thus, extra precautions in the form of compensatory measures have been identified to assure that sources of power are protected to the extent practical and that precautions are taken with regard to the steam-driven-emergency feedwater pump. These precautions are discussed under the compensatory measures section of this document.
Basis for No Sinnificant Hazard Consideration An evaluation of the proposed request for enforcement discretion has been performed in accordance with 10CFR50.91(a)(1) regarding no significant hazards considerations using the standards in 10CFR50.92(c). A discussion of these standards as they relate to this enforcement discretion request follows:
Criterion 1 - Does Not Involve a Significant Increase in the Probability.or Consequences of an Accident Previously Evaluated.
The EDGs 'are backup alternating current power sources designed to power essential safety.
- systems in the event of a loss of offsite power. The EDGs are not accident initiators in any; accident previously evaluated. ' Probabilistic Safety Assessment (PSA) methods were utilized in -
order to fully evaluate the'EDG allowed outage time (AOT) extension proposed in this submittal.
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1CAN079902 Page 9 of12 W results of these analyses indicate there is not a significant increase in the probability of an accident previously evahmted.
The EDGs provide backup power to components that mitigate the consequences of accidents.
The current TSs allow an EDG to be removed from service for an AOT. The requested enforcement discretion extends the current AOT for EDG #2. The proposed change does not allow any more equipment to be removed from service during this time. ~ The proposed enforcement discretion does not affect any of the assumptions used in deterministic safety analysis. By extending the EDG AOT, the consequences of an accident previously evaluated will remain unchan8ed.
Therefore, this enforcement discretion does not involve a significant increase in the probability or consequences of any accident previously evaluated.
Criterion 2 - Does Not Create the Possibility of a New or Differest Kind of Accident from any Previously Evalue.ted.
This requested enforcement discretion does not alter the design, configuration, or method of operation of the p!snt. Thercibre, this request does not create the possibility of a new or different kind of accident f om any previously evaluated.
Criterion 3 - Does Not Involve a Significant Reduction la the Margia of Safety.
The requested enforcement discretion does not affect the Technical Specification limiting conditions for operation or their bases which support the deterministic analyses used to establish the margin of safety. Calculations performed to analyze the change in risk based on this request produced acceptable values, which are included above. These calculated changes in r:sk fall well within that which is normally considered acceptable.
Therefore, this requested enforcement discretion does not involve a significant reduction in the margir ofsafety.
Therefore, based upon the reasoning presented above and the previous discusion of the request,-
Er.tergy Operations has determined that the requested enforcement discretion does not involve a significant hazards consideration.-
EnvironmentalImnact Evaluation ANO has reviewed the proposed enforcement discretion request with respect to its environmental impact.
-10CFR$1.22(c) provides criteria for and identification oflicensing and regulatory actions eligible -
for categorical exclusion from performing an environmental assessment. Per 10CFR$1.22(c)(9), a
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Enclosure to ICAN079902 Page 10 of12 proposed amendment to an operating license for a facility requires no environmental assessment if operation of the facility in accordance with the proposed amendment would not: (1) involve a -
significant hazards consideration, (2) result in a significant change in the types or significant increase in the amounts of any effluents that may be released off-site, or (3) result in a significant 1 increase in individual or cumulative occupational radiation exposure. Entergy Operations, Inc. 1 has reviewed f% proposed discretion request and has determined that it meets the eligibility criteria for ca, ,orical exclusion set forth in 10CFR51.22(c)(9). Pursuant to 10CFR51.22(b), no !
environmental impact statement or environmental assessment need be prepared in connection with the proposed request. The basis for this determination is as follows:
- 1. The proposed request, when implemented, will not involve a significant hazards consideration as described previously in the evaluation.
- 2. As discussed in the significant hazards evaluation, this request, when implemented, will not result in a significant change or significant increase in the radiological doses for any Design Basis Accident. Implementation of the proposed request will not result in a significant change in the types or a significant increase in the amounts of any effluents that may be released off-site.
- 3. The proposed request, when implemented, will not result in a significant increase to the individual or cumulative occupational radiation exposure because it will not alter the physical configuration or modes of operation of any equipment necessary to minimize radioactive releases to the environment.
Comnensatory Measures ANO will follow the other requirements of the ANO-1 TS associated with an inoperable EDO:
- If the other EDG becomes inoperable, TS 3.0.3 will be entered.
- Loss of either Startup Transformer will require entry into TS 3.7.2.A e Operability of EDG #1 will be demonstrard daily.
Off-site power sources and the AACDG will be verified to be available once per shift by use of a checklist (not by starting) while the enforcement discretion is in effect.
No discretionary switchyard maintenance will be allowed. This exclusion does not apply to non-intrusive routine walk-downs.
The system dispatcher will be contacted once per shift and informed of the EDG status along with the power needs of the facility.-
If a tornado or thunderstorm warning is issued in the local area, a dedicated operator will be dispatched for local operation of the AACDG.
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Enclosure to ; s i ICAN079902 Page 11 of12 The AACDG will be treated as a backup to the inoperable EDG and as a protected train.-
component. The AACDG will be posted and controlled as " Protected Equipment."-
The operable EDG, the Startup Transformers #1'and #2 areas, and steam-driven Emergency _-
Feedwater Pump will be posted and controlled as " Protected Equipment."
The ANO-1 On-Shift Operations crew will discuss and review appropriate normal and emergency _-
operating procedures upon or prior to assuming the watch for the first time while the enforcement discretion is in effect and following a period of scheduled days off shift.
The ANO-2 Operations crews will be briefed concerning the ANO-1 EDG activities, W%
these compensatory measures, and the importance of promptly starting and aligning the AACDG -
upon instruction of the ANO-1 Shift Superintendent or upon loss of off-site power. This briefing .
will be performed upon or prior to assuming the watch for the first time while the enforcement
' discretion is in effect and following a period of scheduled days off.
No maintenance or testing that affects reliability of the ANO-1 train associated with the operable EDG is scheduled for either unit during the requested AOT extension period. Testing and-maintenance of other ANO-1 safety-related components will be minimized. Any testing or maintenance on the safety-related ANO-1 systems or components that must.be performed while the AOT extension is in effect will be evaluated by Operations personnel for impact upon the risk to safe operation of the plant before being performed.
Justification For Duration The AOT for EDG #2 expires at 2237 CDT on July 5,1999. The failed bolting has been replaced and engine re-assembly is in progress. Based upon the current statu .,f on-going maintenance activities, EDG #2 is estimated to be ready for post-maintenance Laing during the evening of Tuesday July 6,1999. Testing will require approximately 36 nours. This schedule would have '
the EDG restored to an operable condition on Thursday July 8,1999. Due to uncertainties in these estimates and to allow for unforeseen circumstances,'ANO requests approval of an extension of the AOT for a period not to exceed seven days (to 2237 CDT on July 12).
1 Plant Safety Committee (PSQ Review This proposed ' enforcement discretion was reviewed and approved 'by the ANO-PSC at approximately 1700 CDT on July 4,1999. q h
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ICAN079902 Page 12 'of12 1
Criterion forDiscretion Annroval ANO believes that this request satisfies criterion B.2.l(a) of Part 9900: " Technical . Guidance" of.
the NRC-Inspection Manual, " Operations - Notices of Enforcement Discretion." Criterion B.2.l(a) states, "For an operating plant, the NOED is intended to avoid undesirable transients as a -
result of forcing compliance with license conditions and, -thus,' minimize potential safety consequences and operational risks." The requested enforcement discretion, if granted, will allow sufficient time to complete repairs to EDG #2 in order to prevent an unnecessary plant shutdown J of the unit with one source of emergency power unavailable.
FoRow-un License Amendment Compliance with the limiting condition for operation will occur when EDG #2 is restored to operable status on or before July 12,1999. Since compliance with the Technical Spei&e6ons is restored before expiration of the Enforcement Discretion, no follow-up license s==adn=rd is '
necessary.
Severe Weather Or Other Natural Event Justification This proposed enforcement discretion is not required because of any severe weather condition or any natural event, i
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