IR 05000443/1987011

Insp Rept 50-443/87-11 on 870316-20.No Violations Noted. Major Areas Inspected:Startup Test Program review,post-core Hot Functional Test Witnessing & Test Result Review

ML20210B570
Person / Time
Site:	Seabrook
Issue date:	04/10/1987
From:	Eselgroth P, Wen P NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To:
Shared Package
ML20210B519	List: IR 05000443/1987011 ML20210B515
References
50-443-87-11, NUDOCS 8705050357
Download: ML20210B570 (12)

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U.S. NUCLEAR REGULATORY COMMISSION

REGION I

Report No. 50-443/87-11 Docket N License N NPF-56 Licensee: Public Service of New Hampshire

! Facility Name: Seabrook Station, Unit 1 Inspection At: Seabrook, New Hampshire

! Inspection Conducted: March 16-20, 1987 Inspectors: 7.62ht C. b Peter Wen, Reactor Engineer 4 /9 /87 date Approved by: # 7 Peter Eselgroth, Ch , TPS,'08, DRS 7 date Inspection Summary: Inspection 'on March 16-20, 1987 (Inspection Report Number 50-443/87-11)

Areas Inspected: Startup Test Program review, post-core hot functional test witnessing and test result revie Results: No violations were identifie Note: For acronyms, not identified, refer to NUREG-0544, " Handbook of Acronyms and Initialisms."

i l 8705050357 870421 3 l PDR ADOCK 0500 i G .- ---_

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DETAILS 1.0 Persons Contacted New Hampshire Yankee (NHY)

• S. Barraclough, Lead QC Inspector

• S. Buchwald, QA Supervisor

• R. Cooney, Technical Projects Manager

• Daley, Jr. , Licensing Manager

• P.' Gurney, Reactor Engineering Department Supervisor R. Gwinn, Shift Test Director

• G. Kann, Program Support Manager S. Kenney, Reactor Engineer

• D. McLain, Technical Support Manager

• L. Rau, Reactor Startup Supervisor

• Temple, Licensing Coordinator

• L. Walsh, Operations Manager A. Webster, System Engineer United States Nuclear Regulatory Commission (U.S. NRC)

D. Ruscitto, Resident Inspector The inspector also contacted other licensee administrative and technical personnel during the course of the inspectio * Denotes those present at the March 20, 1987 Exit Meetin .0 Post-Core Hot Functional Testing 2.1 Startup Test Program The licensee began a heat up of the plant on February 10, 1987, and had since conducted the Post-Core Hot Functional Tests. The previous NRC test program inspection coverage was documented in the inspection reports 50-443/87-05 and 50-443/87-09. During this inspection period (March 16-20, 1987), the licensee had completed all post-core hot functional tests with the exception of the Steam Generator Blowdown

! Test (1-ST-54).

On March 19, 1987, after Operations group successfully completed the emergency feedwater surveillance test, the licensee began cooling down the plant to cold shutdown condition for normal plant maintenance and awaiting the low power licens .2 Test Results Review Those Post-Core Hot Functional Test results identified in Appendix A were reviewed by the inspector to verify t, hat:

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test changes were approyed and implemented in accordance with administrative procedures;

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changes did not impact the basic objectives of the test;

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test -deficiencies and exceptions were properly identified, resolved, and resolution accepted;

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the cognizant engineering group had evaluated the test results-and signified that testing demonstrated design conditions were met; and,

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test results compared with established acceptance criteria or were properly resolve Details relating to some of those test results reviewed are described belo .2.1 Reactor Coolant System (RCS) Flow Coastdown (1-ST-12)

The safety analysis performed for a postulated case of complete loss of forced reactor coolant flow was documented in the FSAR Chapter 15.3.2. The analysis result indicates that the flow

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coastdown following a trip of all four RCPs . is adequate to prevent the Departure from Nucleate Boiling (DNB) from occurring. The purpose of this test was to verify the assump-tions used in the safety analysis.

This test was performed to measure the rate of change of reactor coolant flow by simultaneously tripping all four reactor coolant pumps (RCPs). The test was performed on February 25, 198 The permissive P-8 was simulated by lifting leads in the nuclear instrumentation cabinets. This ensured that -low flow (190%) in any operating loop would open the reactor trip breaker The inspector independently reviewed- the data reduction calculation, and noted the following test results:

T2 = 0.12 seconds T2 is the maximum time measured for one of the four loops from the loop 90% low flow trip set point to the change of state of the last reactor trip breake Td= 0.50 seconds Td is the maximum sensor delay time.

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Tg = 0.15 seconds Tg is the gripper release tim _

This value was given by the reactor vendor (Westinghouse) _

The Low Flow Trip Time Delay (T2 + Td + Tg) Acceptance Criteria

= 0.12 + 0.50 + 0.15 = 0.77 seconds < 1.0 seconds The calculated flow coastdown time constant from the measured data is Acceptance Criteria TAUm = 13.03 seconds > 11.77 seconds

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All test results met test acceptance criteri .2.2 Turbine Driven Emergency Feedwater (EF) Start Verification Test (1-ST-53)

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" Over the period from February 19, 1987 to March. 14, 1987, the licensee conducted the various section tests of 1-ST-53. These test results did not satisfactorily demonstrate the operability of the turbine driven EF pump. The shortcomings consisted of:

(1) f ailure to reach an acceptable turbine speed (3350 rpm)

within 60 seconds, and (ii) turbine overspeed trip due to inadequate valve MS-V-395 stroke time. Since then, the licensee had made several changes to balance the main steam supply valve timing sequence with the turbine governor response time. These changes included:

Time Delay Turb. Governor Stroke Time (second) (second) Response MS-V-393 MS-V-394 MS-V-395 MS-V-395 (second)

before the change 5.5- .5- after the change 5-6 5-6 5-6 17 8 Figure 1 illustrates a simplified diagram for the steam ' supply arrangement to the EF Pump Turbin After these changes the 1-ST-53 test was repeated on March 14-17, 1987. The inspector witnessed some portions of testing in progress. Test results and problems that occurred during the test are summarized below:

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Test Results/ Problems Response Time (sec)

Reached full Reached Acc speed Test Date Procedure / Test Conditions 3350 rpm criteria 3570 rpm 3/14/87 - Section Steam Supplied from "A" S/ Cold Start (Steam Supply Line Metal Temperature is below 150 F) 3 <60 3 Pumped Flow to Condensate Storage Tank (CST)

3/14/87 - Section 6.3

- Steam Supplied from "A"_and 3 <60 4 "B" S/G Cold Start

- Pumped Flow to CST

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3/15/87 - Section Steam Supplied from "B" S/G 3 <60 3 Cold Start -,

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3/15/87 - Section 6.4

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- Steam Supplied from "B" S/G 3 <60 3 Cold Start

- Pumped Flow to CST

! 3/15/87 - Section Steam Supplied from "A" and 3 <60 35.0

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"B" S/G Cold Start

- Pumped Ficw to CST With both EFP pumps running

- The Motor Driven EFP was for 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />, the pump suction started for 1-hour run line temperature only increased about 5'F. No overheating in the suction line was observe /15/87 - Section Steam Supplied from "A" S/G 3 <60 3 Hot Start j - Pumped Flow to CST

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Test Results/ Problems

Response Time (sec)

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full Reached Acc speed Test Date Procedure / Test Conditions 3350 rpm criteria 3570 rpm

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3/15/87 - Section Steam Supplied from "B" S/G 3 <60 3 Hot Start

- Pumped Flow to CST 3/15/87 - Section Turbine tripped on overspee Steam Supplied from "A" and The licensee performed a

"B" S/Gs trouble shooting. MS-V-395

- Hot Start- was checked on the stroke

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- Pumped Flow to CST time and was found within the

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required' range. No other problems were identified, j subsequently 1-ST-53 test-

, was resume /15/87 - Section Turbine tripped on overspee Steam Supplied '.om "A" and After'this section's test,

"B" S/Gs the licensee performed a

- Cold Start major maintenance work on

- Pumped Flow to S/Gs valve MS-V-395. Broken pieces of gasket were found in the valve cage around the plug. The valve was repaired prior to resuming the 1-ST-53 tes /17/87 - Section 6.8 i - Steam Supplied from "A" and 4 <60 4 "B" S/Gs

! - Cold Start

- Pumped Flow to CST

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3/17/87 - Section Steam Supplied from "A" and 3 <60 3 "B" S/Gs

- Cold Start

- Pumped Forward to S/Gs The air supply accumulator to MS-V-395 was also verified to maintain the valve in the closed position for 1812 second The pumped forward flow to each S/G was greater than 200 gpm.

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The completion of the 1-ST-53, as described above, has met the test objectives:

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demonstrated the turbine driven EF Pump operability by nine (9) successful starts (7 cold starts and 2 hot starts). Test acceptance criteria required 5 cold start demonstrated that both EF pumps could run on recirculation mode without overheating the suction' line (Section test);

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the EF pump turbine reached an acceptable speed of 3350 rpm within 60 seconds from the start of pump initiation signal; and

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demonstrated the ability of the air supply accumulator to maintain valve MS-V-395 in the closed position for 1812 seconds on a loss of instrument air (Section 6.9 test).

The re-designed EF system and tuning of system response appeared to be functioning well and adequate. The problem associated with water hammer in the steam supply piping system was not observed during these test In addition, the measured flow and pump discharge pressure were consistent with the pump manufacturer predicted performance curv After the completion of the 1-ST-53 test, the Operations group performed EFW surveillance tests 0X1436.04 (EFW 18 Month Auto Activation Surveillance) and OX1436.13 (Turbine Driven EF Pump Post Cold Shutdown or Post Maintenance Surveillance) from March 17 to March 18, 1987. These tests were similar to 1-ST-53 test involving the auto start of EF Pump Turbine. However, on 2 out of 3 runs, the EF Pump Turbine tripped on overspee Work Request (87WR2661) was initiated to investigate the cause. The licensee system engineer determined that Valve MS-V-395 was sticking during these test This problem resulted in the turbine being supplied by erratic steam flow, and eventually causing its trip. The trim in MS-V-395 was replaced with trim (same type) from a spare valve stored in the warehouse on March 18, 198 After the completion of the valve replacement, the licensee conducted six additional tests (1 cold start and 5 hot starts).

The valve (MS-V-395) and the turbine responded satisfactorily during all these test l l

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The inspector expressed concern about the many turbine overspeed trips .that occurred during the'1-ST-53 test and the subsequent EFW surveillance tests. This subject was discussed during the exit meeting. A licensee representative stated that additional turbine reliability tests will be performed ~ when the unit is heated up again. The NRC inspector will follow this in a future i inspection.

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2.2.3 Turbine Driven EF Pump Surveillance Test (0X1436.13)

During the initial operations surveillance test performed at 12:20 on March 18, 1987, due to the steam leak, the EF Pump house filled with the stea To reduce the thermal stress imposed on the EF pump turbine, the surveillance procedure (0X1436.13, Rev. 1) was written to pre-warm the steam line (upstream of MS-V-395) by opening the bypass valves V-396 and V-411, and manually closing the turbine trip throttle valve (MS-V-129). However, this particular line up was not adequate for the revised piping system applicatio The check valves V-404 and 405 are designed to eneck the steam flow only under a full flow condition. During depressurized or low flow condition, the check valves would remain open and allow steam / condensate to pass by.

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On March 18, 1987, during surveillance testing, steam escaped-through steam traps and check valves V-404 and V-405, and vented through a 6" vent line to the outside of the EF pump house (side wall). Due to the vent pipe configuration, a portion of steam flowed through an oil / water separator vent line and went back to the EF pump house floor drain line, and resulted in the EF pump house being filled with the stea The procedure was revised, and reviewed by the Station Opera-

tions Review Committee (SORC) on March 18, 1987, (Meeting N ). The revised procedure employed the same method as 1-ST-53 to start the EF Pump Turbine. The inspector followed the licensee's corrective action and attended the SORC Meeting and observed the subsequent OX 1436.13 retest. No similar problems recurred in the retes .2.4 Followup Anomalies Identified During Post-Core Hot Functional Tests Anomalies identified during post-core hot-functional tests were documented in the NRC inspection report 50-443/87-05. The inspector verified that these anomalies were resolved or followed up by the licensee cognizant group.

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RTD Bypass Loop Flow Verification (1-ST-10)

All four cold leg orifices were changed from 0.50" to 0.668".

The retest results indicated that both hot and cold leg transport times were about 0.53 seconds, and were within the required acceptance criteria of I secon Digital Rod Position Indication (DRPI) Test (1-ST-8)

The computer indication of control bank A through control bank D demand positions was found not being properly updated. The reactor engineer has issued Work Request (87WR1695) to correct this proble Due to its being not a priority item, the work has not yet been completed. This item has no impact on the plant operations because the DRPI indication and step counter demand position in the Main Control Board are both working and performing satisfactoril Control Rod Drive Mechanism (CRDM) Operational Test (1-ST-5)

The noise pulses picked up by the CRDM Acoustic Monitoring System during 1-ST-5 test were thoroughly investigated by the licensee reactor engineer. These included: consulting with Westinghouse, and performing additional stationary gripper current measuremen The licensee reactor engineer concluded that these abnormalities do not pose a problem on the normal plant operation Rod Drop Time Test (1-ST-7)

Rod drop traces from rods B-10 and P-6 exhibited unusual responses during 1-ST-7 test. After consulting this problem with Westinghouse, the licensee reactor engineer parformed a rod drop 2 additional times for each rod t'n March 17, 1987. Test results indicated the current DRPI had reversed polarity for some coils within rod B-10 coil stack "A" and rod P-6 coil stack

"B". This problem apparently has no impact on the DRPI performanc The successful completion of the DRPI test (1-ST-8) confirmed the adequate performance of the DRPI syste .3 Summary Testing for the Post-Core Hot Functional Test with the exception of 1-ST-54, Steam Generator Blowdown Test, was accomplished in accordance with approved procedures, data were acceptable, and test objectives were met or proper test exceptions taken. Anomalies occurred during testing were thoroughly investigated, resolved, or continuously followed u ".

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The reliability of the EF Pump turbine as discussed in the Section 2.2.2 will be reviewed in a future NRC inspectio .0 Independent Calculations / Verifications The inspector performed Independent calculations, and verified that the licensee's RCS flow coascdown (1-ST-12) calculation was correct. The inspector also independently reviewed the EF pump turbine test (1-ST-53)

traces, and verified test results met test acceptanc .0 QA/QC Interface Throughout the entire inspection period, the inspector noted that QA/QC personnel were actively following startup program tests. Appropriate surveillance reports were issue No unacceptable conditions were identifie .0 Licensee Action on Previous Inspection Findings (Closed) Unresolved Items (50-443/85-30-11, 12, 13, 15 and 16): Test Deficiencies were identified during previous pre-operation hot functional tests: Steam Dump Valves, MSIV Bypass Valves, Steam Supply to EF Pump Turbine, EF Pump Recirculation Lines and EF Pump Performanc The licensee has successfully completed these retests using ' test procedures 1-ST-51, 1-ST-53, and 1-ST-55 during the Post-Core Hot-Functional Test period. The inspector witnessed these tests in progress, and reviewed the test results. Test results were acceptable. These items are close .0 Exit Meeting An exit meeting was held on March 20, 1987 to discuss the inspection scope and findings, as detailed in this report (see paragraph 1.0 for attendees).

At no time during this inspection was written material provided to the license Based on the NRC Region I review of this report and discussions held with the licensee representatives at the exit, it was dettrmined that this report does not contain information subject to' 10 CFR 2.790 restriction . . _ _ _ .

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, APPENDIX A'

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POST-CORE HOT FUNCTIONAL TEST RESULTS REVIEW *

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1-ST-5-

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CRDM Operational-Test e

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Rod Drop Time Test- p ,

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1-ST-8 DRPI Test '

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1-ST-9- Pressurizer Spray and Heater Capability ~

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.1-ST-10 -RTD Bypass Loop Flow Yqrificaticin

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1-ST-12 RCS Flow Coastdown u .,

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1-ST-5 EF. Pump Turbine Stop, Valve Trip Dynamic Responsj.. Test -

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1-ST-53 tTurbine Driven EF St <rtVerIficationTest

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1-ST-55 (Stean. Dump System Test *1-ST-55 test result was reviewed at NRC Region I offic This test result is acceptabl :

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