A09188, Submits Results of Review of Allegation R1-90-A-0206 Re Low Flow Setpoint on Standby Pump.Caused by Procedural Noncompliance.Valve Setpoint Change Processed

Submits Results of Review of Allegation R1-90-A-0206 Re Low Flow Setpoint on Standby Pump.Caused by Procedural Noncompliance.Valve Setpoint Change Processed

ML20073C365
Person / Time
Site:	Millstone
Issue date:	01/04/1991
From:	Mroczka E NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To:	Wenzinger E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20073C307	List: A09066, Submits Chronological Summary of Events Leading to Allegation RI-90-A-136 Re in-place Testing Process & Work on Flow Control Valve.Significant Discrepancies Noted Between Allegations & Util Documentation A09076, Submits Results of Review of Allegation RI-90-A-144 Re Steam Jet Air Ejector Radiation Monitor RM 5099 A09163, Submits Results of Review of Allegations R1-90-A-0180 & RI-90-A-0202 Re Inoperability of wide-range Instruments & Annual Preventive Maint on Various Limitorque Operators A09166, Submits Results of Review of Allegation R1-90-A-0208 Re Maint/Weld Repairs on Moisture Separator Reheaters.No Procedural Violations Occurred During Repair Process A09187, Submits Results of Review of Allegation R1-90-A-0205 Re Oil Not Removed from Motor Prior to Removing Motor or Disconnecting Motor Leads.Procedure MP-272OC5 Will Be Clarified A09188, Submits Results of Review of Allegation R1-90-A-0206 Re Low Flow Setpoint on Standby Pump.Caused by Procedural Noncompliance.Valve Setpoint Change Processed ML20073C348
References
A09188, A9188, NUDOCS 9104250192
Download: ML20073C365 (5)

Text

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N465 60M January 4, 1991 Docket No.30-336 J

A09188 Hr. E. C. Venzinger, Chief Projects Branch No. 4 Division of Reactor Projects U. S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, Pennsylvania 19406

Dear Mr. Venzinger:

Millstone Nuclear Power Station, Unit No. 2 RI-90-A-0206 Ve have completed our review of an allegation concerning activities at Hillstone Unit 2 (RI-90-A-0206). As requested in your transmittal letter dated December 6,1990, our response does not contain any personal privacy, proprietary, or safeguards information. The material contained in this response may be released to the public and placed in the NRC Public Document Room at your discretion. The NRC letter and our response have received controlled and limited distribution on a "need to know" basis during the preparation of this response.

. Issue 1 On November 6, 1990, the I&C Department completed IC-2435F, which starts the stator cooling system without the main turbine on line. The procedure sets the flow control valves and records data on pressures and flovs within the system. On November 11, 1990, a lov stator flow condition was identified during two-pump operation which in itself is abnormal since one pump is generally in standby with a low pressure actuation setpoint.

Troubleshooting identified that the flov cor, trol setpoint was not set as required by IC-2435F. Operations does not understand the basis for the lov flov setpoint of the standby pump.

Please discuss'the validity of these statements. Are there procedural compliance issues identified in the problems presented?

l 9104250192 910417 PDR ADOCK 05000336 P PDR OSM2t' AEV 4 88

I l .

Hr. C. C. Venringer, Chief tf. S. Nuclear Regulatory Lommission

• A09188/Page 2 January 4,1991

Background

The procedure reference is incorrect for stator liquid cooling IC-2435F is a non-existent procedure. The correct procedure for this activity is IC-2425F.

containt two pumps. One is operated The stator cooling system continuously, and the other is considered a reserve. An autostart of the reserve pump is provided by a pressure switch, 63-P60A, which is set to start the reserve pump at a system pressure that corresponds to the minimum allovable system flov. For additional reliability, an additionalIC-2425F, switch, 63-P60B, provides a backup autostart signal to the reserve pump.

Stator Cooling System Setup, contains procedural guidance that records system pressures at the required flow settings and uses that information to calculate pressure setpoints for the reserve and backup reserve pressure switches.

This procedure was implemented after completion of maintenance activities on the stator cooling system prior to placing the system in service.

During power operation, it was noted that Troubleshooting the reserve pump could not activities be noted secured and returned to standby status.

that the system pressure developed with one pump operating was belov the It was reset value for the reserve autostart pressure switch, 63-P60A.

also identified that the flow control valve that sets the flovrate to the rectifier cabinet was set at a value of six rather than 32 gpm. This was corrected by AVO H2-90-13938. A setpoint change was then processed to set This the trip value five psi lover than initially calculated via IC-2425F.

These activities setpoint change vas implemented by AVO M2-90-14323.

resolved the problem of not being able to secure the running reserve stator cooling pump.

Response

Stator cooling flov was not abnormally lov on November 11, 1990. On that day, Unit 2 I&C investigated the problem of not being able to secure the reserve stator cooling pump. The reset value of the reserve pump autostart the lead pressure switch was found to be above the discharge pressure of stator cooling pump. The system was found with the flow control valve for the rectifier cooling set at six rather than 32 gpm. It is apparent that the procedural guidance vas not followed.

The procedure var not properly performed. The erroneous rectifier cooling The flov setting was corrected, and a temporary setpoint was implemented.

procedure vill be revised to include additional guidance on setpoint determination.

The pump does not have a lov flov setpoint per se. The system is designed to start the reserve pump at a system pressure value that is equivalent to the lov system flow condition.

s s. *.

a, .

Mr. E. C. Venringer, Chief U*. S. Nuclear Regulatory Commission

• A09188/Page 3 i

January 4, 1991 l Issue _2 On or about November 9, 1990 during recovery from the refueling outage, surveillance procedure SP-2401J. Thermal Margin Lov Pressure (TM/LP)

Function Test, was partially completed in operational mode 3 vith the remainder completed in siode 2. Technical Specification Table 4.3-1 requires TH/LP functional tests to be completed in operational modes 1 and 2.

Are the above statements valid? If so, do technical specifications and procedures allow this surveillance to be segmented in the two operational modea? Please dia:uss.

Background

The Control Element Assembly Vithdraval Prohibit (CVP) is a design feature intended to restrict CEA outvard motion when two or more pretrip conditions occur on the RPS thannels of High Power or Thermal Margin /Lov Pressure (TM/LP). The TM/LP generated CVP is bypassed balov power levels of 10E-4%

by contacts operat ed by the respective channel's vide range nuclear instrumentation.

During 1990, procedure cheges vere mah to functional testing procedures to include alarm and interlak testing. The vide range functional test procedure SP-2401B vas modified to include testing the operation of the relay contacts that serve to remove the bypass the CVP generated from the TM/LP pretrips and checked the proper operation of the TM/LP CVP as part of this testing process. This test is a start-up surveillance and was performed on November 4, 1990 prior to entering Mode 2. The CVP circuitry was therefore tested and operable. ,

The TM/LP functional test procedure SP-2401J was also modified to test the CVP feature. The method used to verify CVP operation only checked the generation of a CVP alarm after the bypass generated from the vide range nuclear instrumentation had been cleared. The procedure did not include the ability to perform the CVP check prior to actual plant conditions reaching greater than 10E-4% power.

No violation of the Unit 2 Technical Specifications occurred.

Response

The statements of Issue 2 are not accurate. The portions of SP-2401J that are required to demonstrate the operability of the TM/LP trip vere performed prior to entry into mode 2, consistent with the requirements of the Technical Specifications.

, *.o.

Mr.' E. C. Vensinger, Chief U' S. Nuclear Regulatory Commission

. A09188/Page 4 January 4, 1991 During 1990, Unit 2 I&C has taken a conservative approach to this the In some cases such as this one, requirement to test alarms.

conservative approach to testing alarms has added confusion to which portions of the procedure must be completed to support the operability of the channel. In addition, this conservative interpretation deviates from the original design objective for the system to be fully testable with the plant in any operating mode. Unit 2 16C is currently This planning to review reviev is intended the requirement for alarm and interlock testing.

to make clear the distinction between those activities in a surveillance procedure that are required to support technical specification system operability from those that are not. Additional procedure refinements are expected.

Issue 3 During a past technical specification review of alarm functions (i.e., LER 90-01), it was identified that .the alarm verification of control element assembly withdraval prohibit was included in the vide range functional surveillance (SP-2401B), but not in TM/LP, High Pover, and " Local Power Density Functional" surveillance tests. During recent procedure upgrades, this change vas not included in these procedures, though it should have been.

Please discuss the validity of the assertion.

Background

The information that was learned during the technical specification reviev included the fact that the same relay that provides the CVP alarm also has contacts that provide the logic for the input to the red control system to accomplish the CVP. These contacts are checked during the Vide Range Nuclear Instrument Punctional Test SP-2401B, but not in the TH/LP functional test SP-2401J and high pover functional test SP-2401F. Once the relay has been verified intact and functional through the accomplishment of SP-2401B, there is no need to further verify its function in SP-2401J and SP-2401F. These latter procedures verify the TM/LP and High Power Channel vill actuate the relay.

Response

Control Element Assembly Vithdraval Prohibit (CVP) alarm is verified for TM/LP and High Power functions in I6C procedures SP-2401J and SP-2401F, respectively. Local Power Density (LPD) has no CVP alarm associated with it. If the issue is related to the alarm, the alarm is being adequately tested with the existing procedures SP-2401B, SP-2401J. and SP-2401F.

4

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Mr. E. C. Venzinger, Chief tr. S. Nucleat Regulatory Commission

. A091BB/Page 5 January 4, 1991 After our review and evaluattun, ve find that none of these issues taken either singularly or collectively present any indication of a compromise of nuclear safety. Ve appreciate the opportunity to respond and explain the basis for our actions. Pleace contact members of my staff if there are any further questions on any of these matters.

Very truly yours, NORTilEAST NUCLEAR ENEhGY COMPANY

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Senior Vice President J. Raymond, Senior Resident Inspector Hillstone Unit Nos. 1, 2, cct V.

and 3

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