IR 05000483/1997015

Insp Rept 50-483/97-15 on 970802-0913.No Violations Noted. Major Areas Inspected:Operations,Maint,Engineering & Plant Support

ML20217B435
Person / Time
Site:	Callaway
Issue date:	09/22/1997
From:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
To:
Shared Package
ML20217B420	List: IR 05000483/1997015 ML20217B416
References
50-483-97-15, NUDOCS 9709250012
Download: ML20217B435 (16)

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ENCLOS_U_RE G.S. NUCLEAR REGULATORY COMMISSION

REGION IV

Docket No.: 50-483 License No.: NPF-30 Report No.: 50 483/97-15 Licensee: Union Electric Company Facility: Caliaway Plant Location: Junction Highway CC and Highway O Fulton, Missouri Dates: August 2 through September 13,1997 Inspector: D. G. Passehl, Senior Resident inspector Approved By: W. D. Johnson, Chief, Project Branch B ATTACHMENT: Supplemental Inf ormation

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EXECUTIVE SUMMARY Callaway Plant NRC Inspection Report 50-483/97-15 Ogerationg

• Operators maintained a professional atmosphere in the control room when reactor power was reduced to 30 percent. Power was reduced as a strategy to improve the axial of fset anomaly (Section 01.2).

Maintenance

• A failure to test load shed and emergency load sequencer inhibit circuits for the emergency diesel generators was identified during reviews in response to Generic Letter 96-01 (Section M1.3).

Ennineerino

• The licensee f ailed to recognize unsatisf actory relay test results. The licensee did not have documentation that other tests that were required were actually performed and were satisf actory. These concerns were related to a modification to install blown fuse indication for the excitation power fuses in Emergency Diesel Generator A (Section E1.1).

• Engine ns continued to aggressively monitor and evaluate methods for improving shutdown margin (Section E8.1).

Plant Suonort

• Material condition and housekeeping in the radwaste filter valve compartments, the pipe chase for radwaste filters and demineralizers, and general floor areas of the 2,030 foot elevation of the radwaste building were good (Section R2.1).

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i Summary of Plant Statug -

- The plant beganithe. report period at 95 percent reactor power. During this inspection period operators performo'd'several gradual load change '

-* :On August 19,1997, operators reduced reactor power to 77 percen *- ;On August 21',1997, operators reduced reactor power to 70 percent. .

• .On September 5,199.7,' operators reduced reactor power to 30 percen * On September. 7,1997, operators returned reactor power to 70 percen The power reductions were performed with a strategy to improve the axial offset anomaly.-

<The goal was to restore axial offset to a value greater than predicted in order to use more--

fuel at the upper elevations of the core, thereby gaining shutdown < margin. - Refer to

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Section E8.1 for further discussion of these effort ;

The plant ended the report period at 70 percent reactor power, t

1. Operations

. 01 -Conduct of Operations ,

O 1.1 ~ General Comments (71707)

The inspector conducted frequent reviews of ongoing plant operations, in general,

.the conduct of. operations was professional and safety-conscious. Plant status, operating problems, and work plans were appropriately address 6d during daily-

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turnover and plan of the-day meetings. Plant testing and maintenance requiring control room coordination were properly controlled. -The inspector observed several-shift turnovers and _noted no problems.

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. 01.2- Gradual Power Reduction to Maintain Shutdown Maroin i "a.- Insoection Scooe (71707)

The inspector reviewed control room activities during the September 6-7,1997, .

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. power reduction to 30 percent reactor power. The inspector's review of

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engineering ' activities associated with the axial offset anomaly is addressed in Section E t b.~ , Observations and Findinos The i'nspector found that operators maintained a professional atmosphere in the

. control room. The pace of activities was such that operators effectively monitored l plant parameters and control board indications. Communication among operators

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• ,a-2-was good and met licenseo management expectations. Operators received good technical support from reactor engineering personne The inspector had no concerns with operator performance during the power reductio O2 Operational Status of Facilities and Equipment O 2.1 Review of Eauinment Taaouts (71707)

The inspector walked down the following tagout:

• Workman's Protection Assurance 23991 - Motor-Driven Auxiliary Feedwater Pump The inspector did not identify any discrepancies. All tags were on the correct devices and the devices were in the position prescribed by the tag .2 Containment Isoi_alion Valve Walkdown (71707)

The inspector walked down containment penetrations to ensure containment integrity using Surveillance Procedure OSP-GP-00001, " Containment integrity Verification," Revision 6, ar.c associated plant drawings. The inspector identified no concern II. Maintenance M1 Conduct of Maintenance M 1.1 General Comments - Maintenance Insoection Scone (62707)

The inspector observed or reviewed portions of the following work activities:

• Work Authorization P543200 -Inspect Condensate Storage Tank to Motor-Driven Auxiliary Feedwater Pump B Check Valve;

• Work Authorizations W607207, W607208, W607267, and, W607269 -

Perform Load Shedder and Emergency Load Sequencer (LSELS) Testing; and

• Work Authorizations A582371C, A582371D, R582371 A, and R5823718 -

Install Blown Fuse Indication for Excitation Power Fuses in Emergency Diesel Generator .

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-3- ghstyalipns and Findinas With the exception of the maintenance described in Section M1.3 and M8.1, the inspector f ound no concerns with the maintenance reviewed nr observed. All work observed was performed with the work packages present and in active use. The inspector frequently observed supervisors and system engineers monitoring job progress, and quality control personnel were present when require M1.2 Qgneral Comments Surveillance inspection Scone (61726)

The inspector observed or reviewed all or portions of the following test activities:

• Test Procedure ISF-AL-OP939, "Fctnal-Press: CST to AFP Suct Hdr Press,"

Revision 10;

• Test Procedure ISF-GN OP936, "Fctnal Press; Ctmt Press Prot," Revision 8:

• Test Procedure OSP-NE-0001 A, " Standby Diesel Generator Periodic Tests,"

Revision 2;

• Test Procedure ETP NF 00001(2), "MDAFW Pump (DPALO1 A(B)) Start inhibit Circuit Test, LSELS Relay K1102(K4102)," Revision 0;

• Test Procedure OSP SA 0017A(B), " Train A(B) SIS CSAS Slave Relay Test,"

Revision 9(10); and

• Test Procedure OSP SF-00001, " At Power Shutdown Margin Calculation,"

Revision 1 Observationji and Findinas Surveillance testing observed during this inspection period was conducted satisfactorily in accordance with the licensee's approved programs and the Technical Specifications. A failure to test load shed and emergency load sequencer inhibit circuits for the emergency diesel generators was identified for further followup (Section M1.3).

M1.3 Enjlyre to Test Load Shed and Ememency Load ScautDcer Inhibit Circuits Inspection Scoce (61726) l The inspector reviewed tne licensee's discovery of the failure to test certain load shed and emergency load sequencer inhibit circuits. The licensee identified this i problem during reviews they were conducting in response to Generic Letter 96 0 l l

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4 The inspector reviewed:

• Engineering Test Procedure ETP NF-00001(2), "MDAFW Pump (DPALO1 A(B))

Start inhibit Circuit Test, LSELS Relay K1102(K4102)," Revision 0;

• Generic Letter 96-01, " Testing of Safety-Related Logic Circuits";

• Operations Surveillance Procedure OSP-SA-0017A(B), Train A(B) SIS-CSAS Slave Relay Test," Revision 9(10);

• Request for Resolution 18377, Revision A;

• SuggestiorcSolution-Occurrence Report 97-1042;

• Technical Specifications: (1) 4.0.3: (2) 4.8.1.1.2.g.2)c)2);

(3) 4.8.1.1.2.g.3)d); and, (4) 4.8.1.1.2.g.4)d); and

• Work Authorizations: (1) W607207, " Check Relays K1117 and K1118 During Performance of OSP-SA-0017A"; (2) W607208, " Check Relays K4117 and K4118 During Performance of OSP-SA-00178";

(3) W607267, " Perform ETP-NF-00001"; and, (4) W607269, " Perform ETP NF-00002." OJ'servations and Findinas On September 4,1997, the licensee discovered that contacts in the load shed and emergency load sequencer circuit that inhibit the auto-start signals of certain pumps were not being tested. The affected pumps were the component cooling water, the essential service water, and the motor-driven auxiliary feedwater pump The contacts and associated relays that inhibit the automatic start of the affected pumps were part of the loading logic for the emergency diesel generators. The inhibit function develops in the load shed and emergency load sequencer logic to prevent out of-sequence loading of the pumps onto the emergency diesel generator The licensee considered the f ailure to test the inhibit function as a f ailure to perform certain Technical Specification surveillances. The licensee determined that the surveillances were:

• Technical Specification 4.8.1.1.2.g.2)c)2) _ verifies that a toss-of-of fsite power signal energizes the auto-connected shutdown loads through the shutdown sequencer;

• Technical Specification 4.8.1.1.2.g.3)d) - verifies on a safety injection signal without loss of offsite power that each emergency diesel generator t

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. auto starts and the offsite power source energizes the auto-connected (accident) loads through the loss-of-coolant accident sequencer; and

• Technica; Specification 4.8.1.1.2.g.4)d) verifies on a safety injection signal that each emergency diesel generator auto-starts and ei.ergizes the emergency busses with permanently connected loads within 12 seconds; and energizes the auto-conrected emergency (accident) loads throu9:. the loss of-coolant accident sequence The shutdown sequencer activates following the detection of undervoltage on the 4160 Volt Class 1E busses. The loss-of-coolant-accident sequencer activates on a safety injection signa Technical Specification 4.8.1.1.2.g stated that the testing be performed "At least once per 18 months, during shutdown." The licensee determined that testing of the sequencers could be performed at power without any detrimental effect Consequently, the licensee developed a testing plan, wrote a safety evaluation, and issued work authorization documents. The licensee justified performing the testing at povser because:

• Technical Specification 4.8,1,1.2.g applied to testing of the entire load shed and emergency load sequencer system. Testing would only be performed on a small part of the entire load shed and emergency load sequencer system;

• The basis for Technical Specification 4.8.1.1.2.g stated that the restriction on performing the testing while shutdown was due to perturbations to the electrical distribution systems that could challenge continued steady state operation. This specific testing would not lead to perturbations to the electrical distribution systems that could challenge steady state operation; and

• The same testing would be performed with sequencer relays that happened to f ail with the reactor at powe The licensee entered Technical Specification 4.0.3 for Emergency Diesel Generators A and B at 9:40 a.m. on September 4,1997. The tests were conducted successfully. The licensee exited Technical Specification 4.0.3 for Emergency Diesel Generator A at 7:12 p.m. on Septernber 4,1997. The licensee exited Technical Specification 4.0.3 for Emergency Diesel Generator B at 8:27 p.m. on September 4,199 Although the tests results were satisf actory, literal compliance with the Technical Specifications may have required that the licensee perform 'his testing while shutdown. Since this testing was performed with the reactor at approximately 70 percent power, it is nossible that the Technical Specification requirements were

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6-not met. Further regulatory analysis of this matter is required; therefore, it will be considered an Unresolved item pending further review (483/9715-01), g.gnrdysions The inspector concluded that te sting of contacts in the load shed and emergency load sequencer circuit was succesful. Literal compliance with the Technical Specifications may have required hat the licensee perform this testing while shutdow lli, Enqineerina E1 Conduct of Engineering E Emernencv Diesel Ggngra12r A Modification lospection Scooe (37551)

The inspector reviewed testing and configuration control for part of Modification 95 1021. This involved the installation of blown fuse indication for the excitation power fuses in Emergency Diesel Generator The inspector reviewed the following:

• Annunciator Response Procedoro OTA-KJ-00121, " Diesel Generator NE01 Controf Panel," Revision 7;

• Class 1 Electrical Drawings for Modification 95-1021;

• Design input Report for Modification 95 1021;

• Engineering Change Notice E-21025, " Relay Setting Tabulation and Coordination Curves System NE (Diesel Generator)", Revision 4;

• Mainteaance Procedure MPE ZZ-QYOS2, " Inspection, Test and Calibration of Protective Current Unbalance Relays, Time Mark Model 2722," Revision 0;

• NRC Information Notice 96-23 " Fires in Emergency Diesel Generator Exciters During Operation Following Unde,tected Fuse Blowing";

• Suggestion-Occurrence-Solution Report 97-0930; and

• Work Authorizations: (1) A582371C, " Bench Test Current Unbalance Relay"; (2) A582371D, " Bench Test Current Transformers"; (3) R582371 A,

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" Verify Calibration of Cr".nt Unbalance Relay"; and (4) R582371B,

" Perform Functional Test of Exciter Fuse Blown Circuitry."

b. Observations and Findinas The licensee installed this modification following evaluation of NRC Information Notice 96 23, " Fires in Emergency Diesel Generator Exciters During Operation Following Undetected Fuse Blowing."

The scope of the modification was comprised of two parts. One part involved installation of a volts por hertz relay in the emergency diesel generator control panel. The licensee installed the relay, but lef t it disconnected, pending load sequence testing during the next refueling outag The second part of the modification involved installation of blown fuse indication for the excitation power fuses. This part of the modification included installation of a current unbalance relay and the associated current transformers in the emergency diesel generator control pane The current unbalance relay was designed to detect failures of the exciter power

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fuses by comparing the current through each of the three phases of the power potential transformer. If the current through one phase was low by some predetermined value, the relay would detect an unbalance condition and initiate a local annunciator, a computer point alarm, and main control board annunciato '

The modification package specified that the current unbalance relay be bench tested prior to installation. The bench test specified a setting for the current un' oalance relay between 23 percent and 27 percen The bench test was performed using Work Authorization A582371C. The inspector found that the B phase setting was 19 percent, and the C phase sotting was 21 percent. These values were out of the specified tolerance stated on Work Authorization A582371C. The licensee signed off Work Authorization A582371C as complete. The inspector noted this problem at the beginning of the outage to install the modification.

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The licensee properly recalibrated the unbalance relay prior tc restoring Emergency Diesel Generator A to operable status. The licensee showed the inspector evidence that the unbalance relay was scheduled for a second calibration prior to the end of the outage. The licensee agreed that the original out-of-tolerance values should have been acknowledged on Work Authorization A582371C, with a note stating that the relay would be recalibrate The licensee initiated Suggestion Occurrence Solution Report 97-0930. The licensee performed an evaluation and determined that a current unbalance relay setting between 15 percent and 35 percent was acceptabl l

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. Although the original bench test results were shown to be acceptable, the inspector determined that the failure to accomplish the bench test of the current unbalance relay according to the specified instructions on Work Authorization A582371C was a violation of 10 CFR Part 50, Appendix B, Criterion V. This f ailure constitutes a violation of minor significance, and is being treated as a Non-Cited Violation, consistent with Section IV of the NRC Enforcement Policy (50-483/9715-02h The inspector reviewed the results of the second calibration of the current unbalance relay which was performed under Work Authorization R582371 A. The results were acceptabl The inspector identified some other concerns relative to the quality of work documentation:

• Work Authorization A582371C specified that testing of the current unbalance relay should be performed at voltages of 100 VAC and 130 VA This was completed but not documented. The modification supervisor contacted relay test personnel, the group who perforrned the test, to verify that the work was performed and was satisf actory. The modification supervisor revised Work Authorization A582371C to show that the work was properly accomplishe * Work Authorization A582371D specified that the current transformers for the unbalance relay be meggered at a value of 500 volts. Th% was completed but not documented. The modification supervisor contacted relay test personnel to verify that the work was performed and was satisfactor The modification supervisor revised Work Authorization A582371D to show that the work was properly accomplishe The inspector reviewed the remaining testing, including the postmodification functional test, and did not identify any further concerns. The inspector reviewed drawings, procedures, and other design documents and noted no concerns, Conclusions The inspector concluded that:

• There was a f ailure to accomplish bench testing of the current unbalance relay according to specified instructions; and

• There was a f ailure to have evidence that other tests which were required were actually performe _______- - - _ _ _ __-____

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/, -9-E8 Miscellaneous Engineering issues (92903)

E8.1 (Ocen) Insoectioi. Followun item 50 483/9714-03: review licensee actions associated with the axial offset anomal The licensee operated the plant at 30 percent reactor power during the weekend of September 6 7,1997. Operators held power at 30 percent for approximately 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, and then returned reactor power to 70 percen The reason for the power reduction was to remove deposits of the lithium-boron compound from the upper regions of the core. The lithium-boron compound was thought to be enhanced in the crud at the upper elevations of the fuel. The boron in the crud layer was the reason for the axial offset anomaly that has caused shutdown margin to erode faster than predicte The licensee expected that reducing reduced reactor power to 30 percent would cause the lithium-boron compound to become more soluble due to lower temperature. The licensee planned to return reactor power to 70 percent without the lithium-boron deposit on the fuel. This would allow more fuel to be used at the top of the core, thereby improving shutdown margi The licensee used some basic assumptions in this approach:

• Coolant temperature at the top of the core would decrease sufficiently in response to a reactor power decrease to allow the lithium-boron to go into solution;

• The lithium-boron compound would not re form as reactor power was increased to 70 percen The licensee had data showing approximately 950 grams cf boron was deposited on the fuel. By ca'culation this was equivalent to about 610 grams of lithium existing in the form of the lithium-boron compound (LiBO 2).

The licensee had also experienced an axial offset anomcly in 1993 (Cycle 9) and performed a similar power reduction to 30 percent reactor power. The licensee removed approximately 600 grams of lithium at that time and expected to remove a similar amount during this recent power reductio The results were not as expected. Only approximately 160 grams of lithium was released from the surface of the fuel while the reactor was at 30 percent powe On the return to 70 percent reactor power, approximately 80 grams of the lithium that was released into the reactor coolant system was re-deposited on the fue Because the re-deposited lithium (as the lithium-boron compound) contained more fresh Boron 10 from the coolant, the axial offset was more negative after the power

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-10-reduction than before the power reduction. Prior to the power reduction, axial of fset was approximately +0.5 percent. After the power reduction, the axial offset was approximately 2.5 percen The licensee made the following overall conclusions:

• The quantity of the lithium boron compound released into the coolant was not as great as expected:

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The re deposition of lithium (as lithiuin boron) as reactor power increased was greater than anticipate The licensee was pursuing other actions:

• Evaluating use of a 5 percent rod worth uncertainty in the shutdown margin calculation to gain additional shutdown margin;

• Evaluating other calculations for shutdown margin to determine if other uncertainties could be reduced:

• Evaluating a plant shutdown to Mode 5 to remove the crud deposit from the fue The inspector noted that the licensee recently revised the Core Operating Limits Report to increase the insertion limits for Control Rod Banks C and D. The increased limits provided additional shutdown margin. The new limit for Centrol Bank C was 100 steps at O percent reactor power, The new limit for Control Bank D was 201 steps at 100 percent reactor powe Technical Specifications 3.1.3.6 and 4.1.1.5.2 require that the shutdown margin in Modes 1 and 2 be greater than or equal to 1300 pcm. As of September 8,1997, shutdown margin dropped to a value of 1737 pc The inspector concluded that the licensee was aggressively monitoring and evaluating ways to improve shutdown margi IV. Plant Syppm1 R1 Radiological Protection and Chemistry Controls R Qq,neral Cgmments (717501 The inspector observed health physics personnel, including supervisnts, routinely tr. ing the radiologically controlled areas. Licensee personnel working in radiologically controlled areas exhibited good radiation worker practice . . - . . . . - - . - -- ~~ .. . ._ .. -- - - - -

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-11-Contaminated areas and high radiation areas were properly posted. Area surveys posted outside rooms in the auxiliary building were current. - The inspector checked a sample of doors, required to be locked for the purpose of radiation protection, and found no problem R2 Status of Radiological Protection and Chemistry Controls Facilities and Equipment R2.1 Radwaste Buildina Tour of 2030 Foot Elevation 'Insocction Scoce (71750)

The inspector accompanied the radwaste and environmental supervisor, and system engineer, on a detailed walkdown of the 2030 foot elevation of the radwaste building. The inspector toured the radwaste filter valve compartments, the pipe chase for radwaste filters and demineralizers, and the general floor areas, Observations and Findinas Contaminated areas and high radiation areas were properly posted. Area surveys posted outside rooms were current. Doors and containers were properly locked for radiation protection purposes.

i Material condition was good and showed improvement since the last inspection. In liquid radwaste demineralizer valve Room 7404A, the licensee repaired several-leaking valves and removed catchments. The inspector did not observe any active

- boric acid leaks. There was dried boric acid at the base of some of the equipment skids that was properly contained. Housekeeping was satisfactor V. Manaaement Meetinas X1 Ex3 Meeting Summary

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The exit meeting was conducted on September 12,1997. The licensee did not express a position on any of the findings in the repor The inspector asked the licensce whether any materials examined during the inspection should be considered proprietary. No proprietary information was identified.

4 The inspector informed the licensee of an inspection followup system numbering error in NRC lnspection Report 50-483/97-14. Section E8.1 of that report

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incorrectly idsntified an unresolved item as 50 483/9707-05. The unresolved item should have been numbered 50-483/9707-06.

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ATTACHMENT 1 SUPPLEMENTAL INFORMATION  ;

PARTIAL LIST OF PERSONS CONTACTED ,

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1!QS.0192 R. D. Affolter, Manager, Callaway Plan H. D. Bono,' Supervising Engineer, Quality Assurance Regulatory Support D. L. Bettenhausen, Supervising Engineer, Quality Assurance -

M. S. Evans, Superintendent, Health Physics J. M. Gloe, Supervisor, Maintenance G. A. Hughes, Supervising Engineer, Independent Safety. Engineering Group K. W. Kuechenmeister, Superintendenti Deugn Engineering _

R.- T. Lamb, Superintendent, Operations .

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. J. V. Laux, _ Manager. Quality Asnurance

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R. D. Miller, Supervisor, Radiological Waste and Environmental J. R. Peevy,- Manager, Emergency Preparedness / Organizational Development G; L. Randolph, Vice President, Nuclear M.'A. Reidmeyer, Engineer, Quality Assurance Regulatory Support

, T. PcSharkey, Supervising Engineer, Nuclear Engineering Systems Mechanical D. R. Waller, Design Engineer, Electrical 4 A.

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WSELQTION PROCEDURES USED 37551 _ Onsite Engineering 01726 Surveillance Observations 62707 Maintenance Observations 71707 Plant Operations 71750 Plant Support Activities 92902 Followup Maintenance 92903 Followup Engineering t

ITEM _S OPENEDJLOSED, AND QlSCUSSED Onened 0715 01 UNR Failure to test load shed and emergency load sequencer inhibit circuits (Section M1.3).

9715 02 NCV Failure to accomplish test per instrucuons on Work Authorization (Section E1,1).

Cloit!d 9715 02 NCV Failure to r:ccomplish test per instructions on Work Authorization (Section E1.1).

~Qi1GM1Ltd 9714 03 IFl Review actions on axial offset anomaly (Section E8.1).