IR 05000278/1986009

Insp Rept 50-278/86-09 on 860318-21.No Violation or Deviation Noted.Major Areas inspected:860317-18 out-of- Sequence Control Rod Withdrawal Event

ML20154R727
Person / Time
Site:	Peach Bottom
Issue date:	03/25/1986
From:	Gallo R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To:
Shared Package
ML20154R720	List: IR 05000278/1986009 ML20154R716
References
50-278-86-09, 50-278-86-9, NUDOCS 8603310160
Download: ML20154R727 (8)

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I U. S. NUCLEAR REGULATORY COMMISSION ,

REGION I

Report N /86-09 Docket N License N DPR-56 Licensee Philadelphia Electric Company 2301 Market Street Philadelphia, Pennsylvania 19101 Facility Name: Peach Bottom Atomic Power Station Unit 3 Inspection At: Delta, Pennsylvania Inspection Conducted: March 18 - 21, 1986 Inspectors: T. P. Johnson, Sr. Resident Inspector J. H. William Resident Inspector Approved By: k ,b k24-/86 Robert M. Dallo, Chief, Reactor Projects date Section No. 2A, DRP Inspection Summary: March 18 - 21, 1986, (Inspection Report 50-278/86-09)

special inspection regarding routine safety and followup regarding an out-of-sequence control rod withdrawal during a Unit 3 startup on March 17-18, 1986. The inspection involved 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br /> by two resident inspector _Re sul t s : The control rod sequence for rods 02-23 and 10-23 was not adequately followed and verified by a second licensed operator when the RWM was out of service. Also, the RSCS function for control rod 02-23 was bypassed by Shift Supervison in the full out position with the rod full i PDR ADOCK 05000278 G PM

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DETAILS

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1. Persons Contacted j 1.1 Licensee Personnel i

• R. S. Fleischmann, Manager, Peach Bottom Atomic Power Station

D. C. Smith, Superintendent, Operations

• W. T. Ullrich, Superintendent, Nuclear Generation Division

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G. A. Hunger, Engineer in Charge, Nuclear Safety Section

, *S. R. Roberts, Operations Engineer Other personnel, including licensed operators, senior licensed i operators, and staff engineers were also contacted.

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• Present at exit interview on site and for summation of preliminary inspection finding .2 NRC Inspection Participants T. P. Johnson, Senior Resident Inspector J. H. Williams, Resident Inspector

2. Purpose and Sequence of Events 2.1 Purpose i On March 17, 1986, the licensee commenced a startup of Unit 3 after

] repairs were completed to the outer screens and the level was restored in the intake basin. On March 18, 1986, during reactor startup,

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the reactor operators deviated from the required control rod with-j drawal sequence in that they left one Group 1 control rod 02-23 full

, in during the startup. Additionally, with the rod worth minimizer i RWM out of service, the rod sequence control system (RSCS) function i for control rod 02-23 was bypassed by the Shift Supervisor and Shift

Superintendent concurrent with the failure of two licensed operators j

to adequately verify the proper control rod withdrawal sequence. A special inspection was conducted to review the licensee's investi-j gation and to independently review the circumstances of this even .2 Sequence of Events (Times Approximate)

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( Date Time Event March 16, 1986 5:13 Unit 3 shutdown due to fouling of the intake basin outer i

screens.

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Date Time Event

.' March 17, 1986 10:18 Unit 3 startup commenced (outer

screens and intake basin returned

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to normal). RWM bypassed due to

computer hardware fault. Two

licensed operators assigned on Unit 3 to monitor control rod withdrawal per TS 3.3.B.3.b.

l 11:00 Shift change occurs; two different

' licensed operators assigned TS

< 3.3.8.3.b duties on Unit 3.

j March 18, 1986 1:20 Rod withdrawal recommenced at j step #6, Group I, rod 58-31.

l 1:28 Rod 10-23 (Group 2) pulled from l 00 to 48 in lieu of required a Group I rod 02-23 which j remained at 00. Rod 02-23 signed off on rod pull sheet as at position 48 by the two assigned

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1:40 Group 1 rods on the pull sheet signed off as completed.

, 1:42 Group 2 rod withdrawal commenced.

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{ 1:47 Rod 10-23 signed off on rod

! pull sheet as withdrawn from 00 j to 48, however rod 10-23 had been fully withdrawn at 1:28 a.m., in

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place of rod 02-23.

I, 4 2:05 Reactor critical on Group 2, rod 42-39 at notch 1 :30 Group 2 rods on the rod pull sheet signed off as completed.

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2:30 - Group 3 rod withdrawal

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2:55 attempted, however rod 02-23 (at position 00) causes RSCS

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rod block. The Shift Superinten-dent and Shift Supervisor bypas-sed rod 02-23 RSCS full out key-

lock switch.

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i Date Time Event i

4:34 Group 3 rod withdrawal completed.

i l 4:50 Group 4 rod withdrawal

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6:11 Last remaining Group 4 rod (30-27) pulled to position 1 :00 Shift change occurs, no further rod withdrawal motio i 7:00- Shift Superintendent requested 7:40 troubleshooting of RWM. RWM re-initialized and returned to

service; insert error received on rod 02-23.

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48 RSCS full out bypass key lock i switch for rod 02-23 returned to normal; rod withdrawal block i occurred due to rod on 02-23 out

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8:44 Two control rods inserted (46-27 and 38-19) pending decision j to shut down.

] 8:55 Reactor manual scram inserted.

l 9:03 Scram reset; reactor in hot

shutdown conditio . Discussion

3.1 Out-of-Sequence Control Rod

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Unit 3 reactor startup commenced on March 17, 1986, at 10:18 The rod worth minimizer (RWM) was out of service due to an apparent inability to initialize computer program. A computer hardware fault alarm could not be cleared by the operators on shift, and it was decided to bypass the RWM with the manual key lock switcF. Technical

Specification (TS) 3.3.B.3.b allows bypassing the RWM as long as a

second licensed operator verifies the control rod program (rod pull

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sequence). The licensee implements this TS requirement with pro-cedure GP-2 Appendix GP-2 Appendix 1 delineates the TS require-i ments, and specifies that the independent verification include j observation of rod motion and rod position for each rod withdrawn.

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Two licensed operators were present during the startup as indicated by log reviews, operator interviews, and the licensee's investigatio Step #13 of the rod pull sheet (GP-2 Appendix 1, Group 1) requires withdrawing rod 02-23 from full in to full out (00 to 48). The GP-2 Appendix 1 signoff sheet indicates that rod 02-23 was withdrawn to position 48 at 1:28 a.m. on March 18, 1986. However, rod 10-23 had been withdrawn in lieu of rod 02-23 as indicated by the computer alarm typer. Based on the licensee's investigation, when the oper-ator came to step #28 of the rod sequence, i.e., control rod 10-23 which was earlier moved to position 48, the following occurred: The operator selected rod 10-23 and was then distracted to verify other plant parameters. When the operator returned to move rod 10-23, he noted it was already at position 48 and gave it an over-travel check, and then proceeded to the next step of the Group 2 sequence. Sub-sequently, the out-of-sequence rod movement was confirmed by the licensee when the RWM was reinitialized and by the licensee, and the NRC, th. rough review of a computer 00-7 Option 2 printout for rod position Failure of the operator to pull the correct rod, and subsequent failure of the second operator to adequately and independently verify that the correct control rod program was being followed with the RWM bypassed is an apparent violation of TS 3.3.B.3.b and procedure GP-2 Appendix 1 (278/86-09-01).

GP-2 Appendix 1, requires that the second licensed operator initial each step (rod pull) on the signoff sheets for independent verifica-tion of rod motion. GP-2 Appendix 1 completed on March 18, 1986, had steps #7 through #22 and steps #24 through #44 indicated as completed by initialing the first step and drawing an arrow through each sign-off bloc Failure to initial each step of the startup rod with-drawal sequence is an apparent violation procedure GP-2, Appendix 1 (278/86-09-02).

3.2 Bypassing of the Rod Sequence Control System (RSCS) Function The Unit 3 reactor startup proceeded through Group 2 rods, and the final step #44 was completed at 2:30 a.m. on March 18, 1986. The RSCS selector switch was placed in the Group A34 position, and a select error and rod block resulted. No Group 3 rod could be selec-ted. Between 2:30 a.m. and 2:55 a.m., the operators attempted to determine the cause of rod block and select error. The process to perform this determination per System Operating Procedure S.4. utilizes the keys and keylock switches which bypass the RSCS full in or full out permissive relays. Prior to bypassing the RSCS, the rod position must be known and the bypass switch must match the actual rod position. The operators determined +.iat control rod 02-23 was causing the rod bloc The RSCS bypass switch was placed in ru ll out position for rod 02-23, and the control rod block cleared. The operators left the control rod 02-23 RSCS bypass switch in full out position and proceeded with the startup with Group 3 rod withdrawal .

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Control rod 02-23 was actually at position 00 (full in) when the RSCS bypass switch was placed in the full out position. TS 3.3. a, 3.3.A.2.d and 4.3.A.2.d, and procedure S.4.3.N allow bypassing the RSCS full in or full out switches if the rod position is known, and the rod is in the correct sequence position, as verified by a second licensed operator. Failure to ensure that the control rod 02-23 position was full out when the RSCS bypass switch was placed in full out position rendered the RSCS function inoperable for rod 02-23 and is a violation of TS 3.3.B.3.a, 3.3.A.2.d, and 4.3.A.2.d, and procedure S.4.3.N (278/85-09-03).

3.3 Manual Scram The licensee proceeded with the startup through Group 3 and 4 control rods to step #88E, control rod 30-27 at position 10. Control rod 02-23 remained at position 00 (full in) with the RSCS bypass switch in the full out position during the continuation at plant startup activitie Between 7:00 a.m. - 7:30 a.m. on March 18, 1986, the shift requested that the RWM be reinitialized and returned to service. At 7:38 a.m.,

the RWM was returned to service by the reactor engineers utilizing the normal RWM reinitialization procedure, and the operators noted that control rod 02-23 indicated an insert error. A check was made of actual rod positions on the full core display and 00-7 option 2 computer printout. Control rod 02-23 was confirmed to be out of-sequence at position 00 (full in). The shift supervisor returned the RSCS bypass key for control rod 02-23'to norma The licensee inserted two control rods pending management decision to shut down, and then manually scrammed the reactor at 08:55 a.m.,

as required by TS 3.3.B.3.c. The inspector was notified of the out-of-sequence control rod at approximately 9:00 a.m. on March 18, 198 The licensee made an ENS call at 9:23 a.m., to report the Unit 3 manual scram and out-of-sequence ro .4 Initial NRC Review At about 9:15 a.m. the inspector proceeded to the control room and observed post scram recovery actions. The inspector verified the control rod 02-23 was out-of-sequence prior to scram (full in instead of full out), by examining the 00-7 option 2 computer printout of rod position The inspector reviewed the control room logs, documents listed in section 4.0, the licensee's investigation, and interviewed licensee engineers and operators. A telephone conference call was held between the NRC and licensee at 5:00 p.m., on March 18, 1986 to the discuss the event and licensee immediate corrective action _ . - _ _ _ . . - _- . _ . .

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' 7 The inspector reviewed the control rod drop accident (CRDA) design j basis and assumption in the FSAR section 14.6.2 and discussed the i subject with the licensee. The FSAR assumes that the RWM, RSCS and operating procedures are in place to ensure the correct control rod sequence. Control rod 10-23, which was moved out-of-sequence, may contribute to a higher than design control rod worth for the CRDA.

4 The licensee indicated that their nuclear fuels group and GE have reviewed the effects of the out-of-sequence control rod condition and the preliminary results indicated a higher rod worth, but within the bounds of the CRDA analysis. The CRDA analysis for the out-of-sequence rod 10-23 is unresolved pending formal licensee evaluation and NRC review. (278/86-09-04)

4. Documents Reviewed

Technical Specifications sections 3.3.A, 4.3.A, 3.3.B, 4.3.8 i

j FSAR Section 7.7, Reactor Manual Control System (RSCS)

i j FSAR Section 14.6.2, Control Rod Drop Accident FSAR Section 7.16, Rod Worth Minimizer Unit 3 Reactor Operators Logbook, March 17-18, 1986

! Unit 3 Computer Typer Log, March 17-18, 1986 j GP-2, Appendix 1, Startup Rod Withdraw Sequence Instructions, Revision 3, 2/21/86 GP-2A, Reactor Startup and Heatup, Revision 21, 11/3/85 l

COL GP-2A, Reactor Startup Order, Revision 65, 2/28/86 i

ST 10.6, Rod Sequence Control System (RSCS) Functional Test, Revision 15, 10/28/85

S.4.3.N, Operation of the Sequence Completion Permissive Switches of the

! RSCS, Revision 4, 12/1/85

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S.4.3.L, Operation of the RSCS During a Reactor Startup, Revision 5, I

7/21/80 i

S.5.5.0, Manual Bypass of the RWM, Revision 2, 12/2/85 l

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5. Management Meetings A verbal summary of preliminary findings was provided to the Superinten-dent, Nuclear Generation Division and the Superintendent, Operations, at the conclusion of the inspection during the management meeting on March 21, 1986. During the inspection, licensee management was periodically notified

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verbally of the preliminary findings by the resident inspectors. No draft inspection report material was provided to the licensee during the inspec-tion. The licensee was informed on March 21, 1986 that this event will be the topic at an enforcement conference to be held on March 27, 1986 with the NRC Region R - .. -. _.