ML18068A485

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LER 97-011-01:on 971012,starting of Primary Coolant Pump with SG Temps Greater than Cold Leg Temps Occurred.Caused by Inadequate Procedures & Operator Decision.Sop Used for Starting Primary Coolant Pump Enhanced
ML18068A485
Person / Time
Site: Palisades Entergy icon.png
Issue date: 10/29/1998
From: Flenner P
CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:
Shared Package
ML18068A483 List:
References
LER-97-011, LER-97-11, NUDOCS 9811090137
Download: ML18068A485 (3)
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FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 EXPIRES 06/30/2001 181 Estimated burden per response to comply with this mandatory information collection request: 50 hrs. Reported lessons learned are incorporated into the licensing p<ocess and fed back to industry. Forward comments LICENSEE EVENT REPORT (LERI regarding burden estimate to the Records Management Branch (T-6 F331, U.S. Nuclear Regulatory Commission. Washington. DC 20555-0001, and (See reverse for required number of to the Paperwork Reduction Project (3150-0104), Office of Management and Budget, Washington, DC 20503. If an information collection does ct;.sits/characters for each block) not display a currently valid OMB control number, the NRC may not conduct or sponsor. and a person is not required to respond to. the information collection.

LITY NAME (1) DOCKET NUMBER 121 PAGE (31 NSUMERS ENERGY COMPANY - PALISADES NUCLEAR PLANT 05000255 1 OF 3 (41

\RTING OF PRIMARY COOLANT PUMP WITH STEAM GENERATOR TEMPERATURES GREATER THAN COLD LEG v1PERATURES i:vc:' llT nl! TE I"\ I C:A IUI oaaRrR 16 AS:P )AT n* ,TE 171 . OTHER C:Al"'llJTIES 1* 11vo1 vc:n IA\

FACILITY NAME DOCKET NUMBER SEQUENTIAL REVISION MONTH OAY YEAR ITH OAY YEAR YEAR NUMBER NUMBER 05000 FACILITY NAME DOCKET NUMBER

) 12 1997 97 -- 011 -- 01 10 29 1998 05000 THIS IS ~I .... R ....... NT TO THE RP-* ,,, nc: 10 rc:a I* IC::hari. nn* nr ~nral 1111

RATING JOE 191 N 20.2201(b) 20.2203(a)(2)(v) x 50. 73(a)(2)(i) 50. 73(a)(2)(viiil _:-.. -**

OWER 20.2203(a)(1 I 20.2203(a)(3)(i) 50. 73(a)(2)(ii) 50. 73(a)(2)(x)

/EL (101 0 20.2203(a)(2)(il 20.2203(a)(3)(ii) 50. 73(a)(2)(iii) 73.71 20.2203(a)(2)(iil 20.2203(a)(4) 50. 73(a)(2)(iv) OTHER 20.2203(a)(2)(iiil 50.36(c)( 1I 50. 73(a)(2)(v) Specify in Abstract below 20.2203(a)(2)(iv) 50.36(c)(2) 50. 73(a)(2)(viil or in NRC Form 366A I .-...**-rr r.nNT41"'T c:na THI~ I C:I 11:11 TELEPHONE NUMBER (Include ArN Codel ip D. Flenner, Sr. Licensing Engineer (616) 764-2544 - ... . *....

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AUSE SYSTEM COlllPONBfT TO EPIX COMPONENT IWIUfACTURER TO EPIX D AB p 8580 N 11.l'lll,l.I
  • "-~EMEllTAL RRIORT *ru ftAI MONTH DAY YEAR EXPECTED ;_ :.

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(If yes, complete EXPECTED SUBMISSION DATE). Ix NO SUBMISSIOI DATE 1151 TRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewrinen lines) (16) j .*:*

October 12, 1997, plant heatup from a short maintenance outage was in progress. At .I

>roximately 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, Primary Coolant Pump (PCP) P- I D was started. Immediately following the pump start, the Primary Coolant System (PCS) I ssure started to rise. Anticipating the PCS pressure rise, operators took manual action and I ited the pressure rise to approximately 280 psia. As a result, no Low Temperature Overpressure itection (LTOP) actuation occurred since the LTOP setpoint at prevailing PCS temperature was

>roximate1y*310 psia. Because PCS pressure rose to this extent in a solid PCS, it was concluded t Technical Specification 3.1.1.h(2) had been violated. Technical Specification 3.1.1.h.(2) uires that forced circulation (starting of the first primary coolant pump) shall not be initiated ess " .. the steam generator secondary temperature is less than or equal to T cold*" to prevent an irpressurization of the PCS. From the amount of PCS pressure rise following start of the pump,

> apparent that the bulk steam generator secondary temperature could not have been less than d* The pressure transient was within design capabilities of the PCS and Shutdown Cooling ,.--*-...

tern. The prevailing plant conditions and operating crew response associated with this event '.

1e been reviewed. The Standard Operating Procedure (SOP) used for starting the primary coolant nps has been enhanced.

9811090137 981029 '

PDR ADOCK 05000255 s PDR

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NRC FORM 366a U.S. NUCLEAR REGULATORY COMMISSION 6/98 LICENSEE EVENT REPORT (LER) g TEXT CONTINUATION FACILITY NAME 111 DOCKET121 LER NUMBER '~1 CONSUMERS ENERGY COMPANY YEAR SEQUENTIAL REVISION NUMBER NUMBER PALISADES NUCLEAR PLANT 05000255 3 98 011 01 TEXT (If more space is required, use additional COIJNIS of NRC Form 366AI (17)

EVENT DESCRIPTION On October 1 2, 1 997, 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 psia. 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 T cold* n 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 Tcoid* 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 1 2 , at a PCS pressure of approximately 250 psi a* in preparation for heat up following a forced outage of relatively short duration, PCS pressure rose to 280 psia. Although this peak PCS pressure did not exceed the LTOP setpoint of 310 psia, nor the Shutdown Cooling System suction piping design rating of 300 psi a 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 Tcoid* A significant pressure increase is not expected if steam generator temperature is below PCS temperature.

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.

NRC FORM 36611 U.S. NUCLEAR REGULATORY COMMISSION 6/98 LIC~_NSEE EVENT REPORT (LER) g TEXT CONTINUATION I

FACILITY NAME I 1l DOCKET12l LER NUMBER 61 CONSUMERS ENERGY COMPANY YEAR SEQUENTIAL REVISION NUMBER NUMBER PALISADES NUCLEAR PLANT 05000255 3 98 011 01 TEXT (II more space 11 required. use additional copies of NRC Form 366Al 117)

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 exp~riencing temperature stratification and the temperature measurement specified in procedure SOP-1 was not a representative temperature.

The prevailing plant conditions and operating crew response associated. with this event. . I have been reviewed. As a result of this review, the conditions under which the steam I generator temperature stratification would occur have been identified. This information I was added as guidance in the Standard Q_perating Procedure (SOP) used for starting the I primary coolant pumps. I 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 clear 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 Taken 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 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.

Long Term Corrective Actions Taken The prevailing plant conditions and operating crew response associated with this event have been reviewed. As a result of this review, the conditions under which the steam generator temperature stratification would occur have been identified. This information was added as guidance in the Standard Operating Procedure (SOP) used for starting the primary coolant pumps.

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