ML20006B480

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LER 89-022-00:on 891227,core Alterations Performed W/Only One of Two Containment Vent Valves Closed,Violating Tech Specs.Caused by Procedural Deficiency.Surveillance Test Procedure Revised to Include Deleted valves.W/900126 Ltr
ML20006B480
Person / Time
Site: Calvert Cliffs Constellation icon.png
Issue date: 01/26/1990
From: Russell L, Sly C
BALTIMORE GAS & ELECTRIC CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-89-022, LER-89-22, NUDOCS 9002020275
Download: ML20006B480 (7)


Text

.- . .

A BALTIMORE OAS AND ELECTRIC l

CHARLES CENTER . P.O. BOX 1475 BALTIMORE, MARYLAND 21203 +

LEON B. RUSSELL  !

MANAGER CCAvt01 CLIFFS NUCLE AN POWER PLANT DEPARTMENT

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January 26, 1990 i

U. S. Nuclear Kegulatory Commission Docket Nos. 50-318 Document Control Desk License Nos. DPR 69 '

Washington, D. C. 20555

Dear Sirs:

The attached LER 89-22, Revision 0, is being sent to you as required under 10 7 CFR 50.73 guidelines.

Should you have any questions regarding this report, we would,be pleased to discuss them with you.

Very truly yours, f- , -

/t4M L . B . Ri. n ' 1. -i Manager Gal mrt Cliffs Nuclear Power Plant Department CDS/lr l cc: William T. Russell Director, Office of Management.Information and Program Control Messrs: G. C. Creel C. H. Cruse

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with TS 3/4.9.14 The immediate cause of the event was n' procedural deficiency. One of the containment vent valves was erroneously deleted from the STP which satisfied TS 4.9.14. The root cause was an error in a review to assure that the STP satisfied the TS limiting conditions for containment penetrations during core alternations or movement of l irradiated fuel within containment. The error resulted from a failure to recognize  !

that a double valve isolation is required for the containment vent penetration in MODE  ;

6. The error resulted in the deletion of one of the redundant valves from the MODE 6 STP to verify containment integrity.

The STP's for both units were revised to include the deleted valves. The valves will be flagged referencing the Basis section of the Technical Specifications. The Surveil-lance Test Program instruction has been revised to reduce occurrence of such events.

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l I. DESCRIPTION OF EVENTS On December 27, 1989, at 1415 hours0.0164 days <br />0.393 hours <br />0.00234 weeks <br />5.384075e-4 months <br />, a Technical Specification (TS) violation was discovered to have had existed at Calvert Cliffs Unit-2. The violation was -

the result of performing cor' . iterations and/or movement of - irradiated fuel l within containment without asm.ing that both containment vent' isolation valves were closed in accordance with TS 3/4.9.14 The event was-discovered during a concentrated effort to identify discrepancies between TS's and associated Surveillance Test Procedures (STP's). At the time the event was discovered.

Unit-1 was in cold shutdown with the reactor coolant- system at 105 F and 10 psig and Unit 2 was defueled.

Calvert Cliffs TS 3.9.14 requires that during core alterations or movement of:

irradiated fuel within the containment, the containment vent isolation valves shall be closed. There are two containment vent isolation valves, MOV-6900 (inside containment) and MOV-6901 (outside containment). TS 4.9.14 requires that the containment vent isolation valves be determined to be closed within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> prior to the start of, and at least once per 7 days during, core alterations or movement of irradiated fuel within the containment, j Surveillance Test Procedures 0-55A-1 and -2 are titled, " Containment Integrity ,

Verification (Mode 6)". These procedures were originally created to satisfy - the requirements of TS 3/4.9.4, " Refueling Operations, Containment Penetrations". i TS 3.9.4 requires that during core alterations or movement of irradiated fuel within the containment that each penetration providing direct access from }

containment to outside shall be either;

1. Closed by an isolation valve, blind flange, or manual valve, or j i

l 2. Be capable of being closed by an operable automatic containment purge valve.

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i TS 4.9.4 requires verification of the above within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> prior to the start of, and at least once per 7 days during, core alterations or movement of i

irradiated fuel inside containment.  !

Due to the similarity between TS 3/4.9.4 ,and 3/4.9.14 and their surveillance requirements, they are both included in STP 0-55A-1 and 2. The major difference between the two is that TS 3/4.9.14 requires a double isolation of the- i containment vent containment penetration during refueling operations while TS i 3/4.9.4 requires only a single isolation of all other containments penetrations, i TS 3/4.9.4 is part of the original Calvert Cliffs Technical Specifications. TS i

3/4.9.14 was added to Unit-1 and -2 TS's .as part of amendment 88 and 75, l respectively. These TS amendments became effective on November 17, 1983 and l June 6,'1984 for Units 1 and 2, respectively. .Both Units had appropriate changes made to STP 0-55A to include both MOV-6900 and 6901.

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12l2 H 0l0 0P OF 0 l6 During the first quarter of 1987, a review of all penetrations that could provide a direct flow path from inside to outside containment was conducted. The intent of this review was to provide increased confidence that a direct path could not be inadvertently created through a penetration that could be overlooked during core alterations. A set of acceptance criteria was established. One of these acceptance criteria was to identify all penetrations that could provide a direct flow path from inside to outside containment and assure that all such penetrations were isolated by at least one valve, blank flange, or other approved barrier.

The penetration review determined that penetration 48A, the containment vent outlet, provided a direct path to the plant vent system (outside containment).

It was therefore concluded that the MOV-6900 should be maintained shut. It was not recognized that TS 3/4.9.14 required both MOV-6900 and 6901 to be maintained closed in MODE 6. STP 0-55A-2 was revised to reflect the findings of the review. STP 0 55A-2, revision 11, dated April 10, 1987 deleted Unit-2 MOV 6901 based on the above noted review and STP 0 55A-1, revision 13, dated March 1, 1989 deleted Unit-1 MOV-6901.

After the deletion of MOV-6901 from STP 0-55A 1 and -2, each STP was performed several times. STP 0-55A-1 was performed twice, but not for core alteration purposes. Thus, no violation of TS 3/4.9.14 actually occurred for Unit-1. STP 0-55A-2 on the other hand, was performed several times for the purposes of allowing-core alterations during Unit-2 outages between March and July 1987 and between March 1989 and present. Thus, several violations of Unit-2 TS 3/4.9.14 did actually occur.

l l II, CAUSE OF EVENT The cause of this event was procedural deficiency. The procedures, STP 0-55A-1 and 2, did not contain both containment vent isolation valves MOV-6900 and 6901.

The root cause 4 the event was an error in the previously discussed 1987 review

! of penetratior. that could provide a direct path from inside to outside containment. Tim review was done to assure that the single isolation conditions of TS 3/4.9.4 were satisfied for all containment penetrations, but did not recognize the required double isolation of the containment vent isolation valves.

This led to the deletion of the redundant containment isolation vent valve MOV-6901 from STP 0-55A-2 on April 10, 1987 and from STP 0-55A-1 on March 1, 1989.

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olo ol4 0F 0 16 III. AH6LLSI.S OF EVENT The event is considered reportable under 10 CFR 50.73(a)(2)(1)(B) because core alterations were performed for Unit-2 during outages in 1987 and 1989 without -

verifying that both containment vent isolation valves were closed in accordance with TS 3/4.9.14. There was no such violation of the TS for Unit 1 because no core alterations or movement of irradiated fuel were performed during the period that MOV-6901 was removed from STP 0 55A-1.

TS 3/4.9.14 was added to Unit 1 and -2 TS's by amendments 88 and 75, respectively. The valves . were formally designated as hydrogen purge outlet valves. The TS amendments proposed that the hydrogen purge outlet valves be  :

re designated as containment vent isolation valves, and be required to close automatically in less than 20 seconds as verified by periodic testing.

In Modes 5 and 6, the TS amendment proposed the addition of the TS .3.9.14.

This new TS required both containment vent isolation valves remain closed during core alternations or mov'ement of irradiated fuel within containment. The basis for this requirement is that the closure restrictions- on these valves are sufficient to restrict radioactivo material release from a fuel element rupture based upon the lack of containment pressurization potential while in the refueling mode, c

TS 3.9.4 addresses the required status of all other containment penetrations in modes 5 and 6. The TS requires a single isolation . of all applicable containment penetrations by an isolation valve, blind flange, or manual valve.

The basis for this requirement is that the closure restrictions are sufficient to restrict radioactive material release from a fuel element rupture based upon the

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lack of containment pressurization potential while in the refueling mode.

It is concluded that no adverse safety consequences resulted from.this event, At all times during core alterations and movements of irradiated fuel within i containment the TS surveillance requirement was satisfied for MOV-6900. Thus, l sir.gle isolation of this particular containment penetration was maintained. The l single closed isolation valve would have effectively prevented the- release of l radioactive material from a fuel element rupture in the refueling mode. Why TS l 3/4.9.14 requires double isolation of a containment penetration and TS 3/4.9.4 i- requires only single isolation of similar penetrations is unknown. +

The total duration of MOV-6901 being deleted from STP 0-55A-2 was from April 10, 1987 . to November 2, 1989,'a total of two and one-half years. There .were no components or systems which were inoperable and/or out of service- whiah contributed to this event. No plant systems or component failures resulted from l this event.

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Ol0 'Ol 5 OF O l6 IV. CO'1RECTIVE ACTIONS

1. Effective November 2, 1989, STP 0-55A-1 and 2 were revised to include MOV 6901,
2. MOV 6900 and 6901 will be flagged in STP 0 55A 1 and 2 referencing it to the Basis section of the Technical Specifications.
3. The Surveillance Test Program instruction has been revised to reduce occurrence of events such as the deletion of MOV-6901 fror. 0-55A-1 and 2.

Changes include the addition of Functional Surveillance Test Coordinators (FSTCs) who are responsible for coordinating the preparation of STPs and revisions to STPs. The FSTCs provide focused, discipline-specific control of surveillance test content, review and scheduling.

I V. ADDITIONAL INFORMATION I There have been several previous reportable events caused by inadequate, incomplete, or lack of procedures at Calvert. Cliffs. However, no previous similar reportable events have occurred at Calvert Cliffs involving inadvertent deletion of TS requirements from STP?s.

Identification of Components Referred to in this LER-Component 'IEEE803 IEEE805 EIIS Funct. System ID i (1) MOV-6900 VTV BB (1) 2 MOV-6901 VTV BB I

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