ML18067A775

LER 97-011-00:on 971012,primary Coolant Pump Was Started W/Sg Temperatures Greater than Cold Leg Temperature.Caused by Inadequate Procedures & Operator Decision Making.Critique of Event Conducted W/Operators Involved

ML18067A775
Person / Time
Site:	Palisades
Issue date:	11/11/1997
From:	Roberts W CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:
Shared Package
ML18067A774	List: ML18067A773 ML18067A775
References
LER-97-011, LER-97-11, NUDOCS 9711180198
Download: ML18067A775 (4)

Text

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104

{4/95) EXPIRES 4/30/98 ESTIMATED BlRDel PER RESPONSE TO COMPLY W1lH THIS MANDATORY INFORMATION COLLECTION REQUEST: 5-0.0 HRS. REPORTED LESSONS LEARNED ARE INCORPORATED LICENSEE EVENT REPORT (LER) INTO THE LICENSING PROCESS AND FED BACK TO INDUSTRY. FORWARD COMMENTS REGARDING CURDEN ESTIMATE TO THE INFORMATION ANO RECORDS MANAGEMENT BRANCH (T-8 F33), U.S. t.\JCLEAR REGULATORY COMMISSION, WASHINGTON, DC 2055!>-

0001, AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104, OFFICE OF

{See reverse for required number of digits/characters for each block) MANAGEMENT AND BUDGET. WASHINGTON. DC 205-03 DOCKET NUMBER {2) Page (3)

FACILITY NAME {1) CONSUMERS ENERGY COMPANY PALISADES NUCLEAR PLANT 05000255 1 of 4 TITLE (4) LICENSEE EVENT REPORT 97-011 - STARTING OF PRIMARY COOLANT PUMP WITH STEAM GENERATOR TEMPERATURES GREATER THAN COLD LEG TEMPERATURES EVENT DATE (5) LER NUMBER (6) REPORT DATE (7) OTHER FACILITIES INVOLVED (8)

MONTH DAY YEAR YEAR I SEQUENTIAL NUMBER REVISION NUMBER MONTH DAY YEAR FACILITY NAME DOCKET NUMBER 05000 FACILITY NAME DOCKET NUMBER 10 12 97 97 - 011 - 00 11 11 97 05000 OPERATING THIS REPORT IS SUBMITIED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check one or more) (11)

~ODE (9) N 20.2201{b) 20.2203(a)(2)(v) x 5o. 73(aJ(2)(il 50.73(a)(2)(iii)

I I I POWER 20.2203{a)(1) 20.2203(a)(3)(i) 50.73{a)(2)(ii) 50.73(a)(2)(x)

LEVEL (10) 0 20.2203(a)(2)(i) 20.2203(a)(3)(ii) 50. 73(a)(2)(iii) 73.71 20.2203(a)(2)(ii) 20.2203(a)(4) 50.73(a)(2)(iv) OTHER l;!,0,' :;*>*--*. 20.2203(a)(2)(iii) 50.36(c)(1) 50.73(a)(2)(v) Specify in Abstract below or I 20.2203{a\12lliv) 50.361c\12l LICENSEE CONTACT FOR THIS LER (12) 50.731a\12\lvii\ in NRC Form 366A NAME William L Roberts, Licensing Engineer TELEPHONE NU~BER (Include Area Code)

(616) 764-2976 COMPl,..ETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT 113\

CAUSE SYSTEM COMPONENT MANUFACTURER REPORTABLE CAUSE SYSTEM COMPONENT MANUFACTURER_ REPORTABLE TONPRDS TONPRDS SUPPLEMENTAL REPORT EXPECTED (14) MONTH DAY YEAR x

I YES If ves COMPLETE EXPECTED COMPLETION DATE I NO EXPECTED SUBMISSION DATE 115\ 01 30 98 ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) (16)

On October 12, 1997, plant heatup from a short maintenance outage was in progress. At approximately 1926 hours0.0223 days <br />0.535 hours <br />0.00318 weeks <br />7.32843e-4 months <br /> with the plant at 250 psia and 130°F, plant prerequisites and checklists had been completed and Primary Coolant Pump (PCP) P-500 was started. Immediately following the pump start, the Primary Coolant System (PCS) pressure started to rise. Anticipating the PCS pressure rise, operators took manual action and limited the pressure rise to approximately 280 psi a. As a result, no Low Temperature Overpressure Protection (LTOP) actuation occurred since the LTOP setpoint at prevailing PCS temperature was approximately 310 psia. Because PCS pressure rose to_ this extent in a solid PCS, it was concluded that Technical Specification 3.1.1.h(2) was violated. Technical Specification 3. 1.1.h.(2)"requires that forced circulation (starting of the.

first primary coolant pump) shall not be initiated unless " .. the steam generator secondary temperature is less than or equal to Tcold*" to prevent an overpressurization of the PCS when starting a primary coolant pump. From the amount of PCS pressure rise following start of the pump, it is apparent that the bulk steam generator secondary temperature could not have been less than Tcold* The pressure transient was within design capabilities of the PCS and Shutdown Cooling System.

9711180198 971111 PDR ADOCK 05000255 S PDR

NRC FORM 366a U.S. NUCLEAR REGULATORY COMMISSION 4195 LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION G

FACILITY NAME (1 I DOCKETl2\ LER NUMBER 16\

CONSUM~RS PALISADES NUCLEAR PLANT ENERGY COMPANY 05000255 YEAR I SEQUENTIAL NUMBER REVISION NUMBER 4

97 - 011 - 00 TEXT (If more space 1s required, use add1t1onal copies of NRC Form 366A) (17)

EVENT DESCRIPTION On October 12, 1997, plant heatup from* a short maintenance outage was in progress. At approximately 1926 hours0.0223 days <br />0.535 hours <br />0.00318 weeks <br />7.32843e-4 months <br /> with the plant at 250 psia and 130°F, plant prerequisites and checklists had been completed and Primary Coolant Pump (PCP) P-50D was started. Immediately following the pump start, the Primary Coolant System (PCS) pressure started to rise. Anticipating the PCS pressure rise, .operators took manual action and limited the pressure rise to approximately 280 psia. As a result, no Low Temperature Overpressure Protection (L TOP) actuation occurred since the LTOP setpoint at prevailing PCS temperature was approximately 310 psia. Because PCS pressure rose to this extent in a solid PCS, it was concluded that Technical Specification 3.1.1.h(2) was violated. Technical Specification 3.1.1.h.(2) requires that forced circulation (starting of the first primary coolant pump) shall not be initiated unless ".. the steam generator secondary temperature is less than or equal to Tcold*" to prevent an overpressurization of the PCS when starting a primary coolant pump. From the amount of PCS pressure rise following start of the pump, it is apparent that the bulk steam generator secondary temperature could not have been.

less than Tcold* The pressure transient was within design capabilities of the PCS and Shutdown Cooling System.

ANALYSIS OF EVENT During plant cooldown and heat up, PCS temperature and pressure are controlled to ensure that reactor vessel nil ductility temperature (NOT) limits and Shutdown Cooling System design limits are complied with. Immediately after plant shutdown, when primary coolant pumps remain in operation, the bulk steam generator temperature remains the same as the PCS. Once the primary coolant pumps are shut down and flow through the steam generators is stopped, the Shutdown Cooling System can lower the PCS temperature below that of the still warm steam generators.

During the start of the first primary coolant pump on October 12 , at a PCS pressure of approximately 250 psia in preparation for heat up following a forced outage of relatively short du-rati6n~-P-CS pressure rose to 280 psia. Although this peak PCS pressure did not exc::eed_the

• LTOP setpoint of 310 psia, nor the Shutdown Cooling System suction piping design rating of 300 psia at 350°F, the peak pressure did exceed the more conservative maximum pressure allowed by SOP 3 of 270 psia when on shutdown cooling. The rise in pressure and the rise in PCS temperature indicates that Technical Specification 3.1.1.h.(2) was violated. This specification states that the first primary coolant pump shall not be started unless steam generator secondary temperature is less than Tcold* A significant pressure increase is not expected if steam generator temperature is below PCS temperature.

NRC FORM 366a U.S. NUCLEAR REGULATORY COMMISSION 4195 LICENSEE EVENT REPORT (LER) g TEXT CONTINUATION FACILITY NAME 11 l DOCKET12l LER NUMBER 61 CONSUMERS ENERGY COMPANY PALISADES NUCLEAR PLANT 05000255 YEAR I SEQUENTIAL NUMBER REVISION NUMBER 4

97 - 011 - 00 TEXT (If more space 1s required. use add11ional copies of NRC Form 366A) (1 !)

Review of this event has determined that the procedural guidance for starting primary coolant pumps was inadequate. The procedure did not provide sufficient guidance to correctly determine steam generator temperatures in this specific circumstance.

Second, due to the short duration of this cold shutdown period; a decision was made not to recirculate the steam generators for chemistry purposes. This led to the steam generators experiencing temperature stratification and the temperature measurement specified in procedure.

SOP-1 was not a representative temperature.

Our review is continuing and we will further evaluate the prevailing plant conditions and operating crew response associated with this event to assure that all root cause contributors and necessary corrective actions are identified. The results of our completed review will be provided in a supplement to this LER.

SAFETY SIGNIFICANCE Technical Specification 3.1.1.h.(2) prevents an overpressurization of the PCS when starting a primary coolant pump. The actual PCS pressure did not exceed the set point for the Low Temperature Overpressure Protection System. The Shutdown Cooling System suction piping is rated for 300 psia at 350 F and the pressure excursion did not exceed this system design rating.

Therefore, there were no significant consequences of this event.

CAUSE OF THE EVENT

. Although the root cause analysis continues, it is dear that inadequate procedures and operator decision making contributed to this condition. We are reviewing the circumstances surrounding the event to assure that other potential contributors to the root cause are properly identified and .

evaluated ..

CORRECTIVE ACTIONS Immediate Corrective Actions The Operations Superintendent/Acting Operations Manager conducted a critique of this event with licensed operators that were involved. The emphasis was on compliance with Technical

• NRC FORM 366a U.S. NUCLEAR REGULATORY COMMISSION 4195 LICENSEE EVENT REPORT (LER) g TEXT CONTINUATION FACILITY NAME 11 \ DOCKET12l LER NUMBER 16\

CONSUMERS ENERGY COMPANY PALISADES NUCLEAR PLANT 05000255 YEAR I SEQUENTIAL NUMBER REVISION NUMBER 4

97 - 011 - 00 TEXT (If more space 1s required, use additional copies of NRC Form 366A) (17)

Specifications and making conservative decisions with respect to Technical Specification limits.

This was completed on October 31, 1997. Subsequently, all active license holders within the Operations Department were briefed on this event.

Proposed Corrective Actions

1. Strategies for primary coolant pump starting will be reviewed and the procedure will be revised to incorporate clearer guidance for steam generator conditions and temperature measurements.