IR 05000341/1987006

Insp Rept 50-341/87-06 on 861229-870209.Violations Noted: Failure to Verify Adequacy of Design & Failure to Preoperational Test & Surveillance Test Hydrogen Recombiner Sys.Insp Based on 861226 Event

ML20211J332
Person / Time
Site:	Fermi
Issue date:	02/20/1987
From:	Greenman E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
Shared Package
ML20211J267	List: ML20211J263 ML20211J332
References
50-341-87-06, 50-341-87-6, NUDOCS 8702260417
Download: ML20211J332 (5)

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U.S NUCLEAR REGULATORY COMMISSION

REGION III

Report No. 50-341/87006(DRP)

Docket No. 50-341 Operating License No. NPF-43 Licensee:

Detroit Edison Company 2000 Second Avenue Detroit, MI 48226 Facility Name:

Fermi 2 Inspection At:

Fermi Site, Newport, Michigan Inspection Conducted:

December 29, 1986, through February 9, 1987 Inspectors:

W. G. Rogers M. E. Par er g & &,;,.=-o

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U Approved By:

E. G. Greenman, Deputy Director DivisionofReactorProjects Date Inspection Summary Inspection on December 29, 1986, through February 9, 1987 (Report No.

50-341/87006(DRP))

Areas Inspected:

Special unannounced inspection by two resident inspectors of the events surrounding the discovery on December 26, 1986, of both (24.409.01) divisions of hydrogen thermal recombiners being ino)erable.

Results:

Three violations were identified (failure to verify tie adequacy of design, failure to preoperational test and surveillance test the hydrogen recombiner system utilizing the designed cooling water system, and the plant entered Operation Condition 2 on eleven occasions with both divisions of the hydrogen recombiner system inoperable - Paragraph 2).

0702260417 B70220 PDR ADOCK 05000341

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DETAILS 1.

Persons Contacted a.

Detroit Edison Company

+* Frank Agosti, Vice President, Nuclear Operations S. Becker, Maintenance B. Catanese, Maintenance Staff

+*S. Catola, Chairman, Nuclear Safety Review Group

+0. K. Earle, Technical Engineer

• S. Frost, Licensing S. Heard, Assistant Operations Engineer

+*J. Leman, Superintendent, Maintenance and Modification

+*R. Lenart, Plant Manager, Nuclear Production

+*R. May, Maintenance Engineer

+*G. Ohlemacher, I&C Assistant Maintenance Engineer

+*W. Orser, Vice President, Nuclear Engineering

• R. Poche, Licensing

+*E. Preston, Operations Engineer

+T. Randazzo, Director, Regulatory Affairs

• L. Simpkin, Nucleu Engineering Director

+*F. Sondgeroth, Licensing

+*B. R. Sylvia, Group Vice President, Nuclear Operations

+*G. Trahey, Director, Quality Assurance

+*W. Tucker, Acting Superintendent, Operations b.

U.S. Nuclear Regulatory Commission

+*M. Parker, Resident Inspector

+*W. Rogers, Senior Resident Inspector

+M. Farber, Reg #cnal Inspector

• Der.es those attending exit meeting on January 15, 1987.

+ Denotes those attending exit meeting on February 3, 1987.

Other personnel were contacted as a matter of routine during the inspection.

2.

Hydrogen Recombiner System On December 26,fication required six month functional surveillance 1986, at 1 Technical Speci (24.409.01) on the Division II hydrogen recombiner system.

The surveillance was being performed using the Residual Heat Removal keep-fill (demineralized water) system as a source of cooling water for the hydrogen recombiner system.

During the surveillance, the licensee initiated the Residual Heat Removal (RHR) system in the torus cooling mode in preparation for HPCI testing.

At the same time the RHR system was started, the air temperature of the hydrogen recombiner began decreasing.

This prevented successful completion of the hydrogen recombiner surveillance.

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s, Technical Specification 4.6.6.1 states, "Each drywell and suppression chamber hydrogen recombiner system shall be demonstrated OPERABLE at least once per six months by verifying during a recombiner system functional tast that the heater outlet gas temperature increases to greater than or equal to 1150 F within 75 minutes and is maintained for at least one hour." The licensee was unable to satisfy these requirements upon initiation of the RHR system and subsequently declared both divisions of hydrogen recombiners inoperable and took appropriate action to comply with the applicable Technical Spec'fication action statements.

The licensee initially determined that the inability to achieve outlet gas temperature was due to excessive cooling water flow.

The cooling water flow to the hydrogen recombiners had been provided at about 60 psig through the RHR keep-fill system. When the RHR system was started, the cooling water pressure was increase'd to about 220 psig which resulted in greater flow and thus more coeling.

This resulted in a decrease of the thermal recombiner temperature.

The licensee subsecuently adjusted the cooling water flow, repeated the surveillance, and ceclared both divisions of the thermal recombiners operable on December 27, 1986.

In order to satisfy operability concerns addressed by the resident inspectors, the licensee repeated the surveillance with the manual isolation valve full open, simulating the original test conditions.

The Division I thermal recombiner passed the surveillance on January 8,1987, but Division II failed on January 9,1987.

After the second surveillance failure on the Division II thermal recombiner system on January 9,1987, pressure gauges were installed on the cooling water line.

The RHR pressure to the unit was measured at 190 psig and the pressure to the blower seal was measured at 140 psig.

Rough flow measurements determined that approximately three gpm were provided to the seal with one and one-half gpm at the seal outlet.

The licensee subsequently determined that the blower seal was leaking internally at the higher RHR pressures.

Discussions with the seal manufacturer, Durametallic Corporation, concluded that the springs in the blower seal will compress at 39 psid and could allow water to enter the blower cavity.

Vendor drawings identified that the blower seal was designed for a cooling water flow of one gpm at 10 psi 15 psi.

Rockwell International vendor drawing No. N019560002 provided for an RHR system pressure to the hydrogen recombiners of 100 psi minimum, while Rockwell internal letter to H. L. Yobs from S. A. Itow dated January 13, 1987, indicates 100 psi.

Neither specified the actual 220 psi to the unit.

The licensee specification 3071-107 dated April 13, 1972, specifically identified a 250 psig(water source to the341/87006-01(DRP)) o recombiner units.

This is considered a violation 10 CFR 50, Appendix B, Criterion III, Design Control, for failure to appropriately verify the adequacy of design.

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A review of the preoperational test program identified that the thermal T4804.001,"preoperational' test, "T4804 Thermal Recombiner System PRET recombiner Revision 2, allowed the use of the RHR system or an alternate source if needed to supply cooling water.

The PRET identified that the RHR keep-fill system was utilized in the-preoperational test and that no specific intent was made to utilize the higher RHR pressures to verify proper system operation.

The system was operated on nyeral occasions and each time the RHR keep-fill system was used as a source of cooling water.

Through discussions with personnel there were several reasons that the RHR was not utilized:

(1) RHR pump availability; (2) economic factors, and (3) RHR keep-fill availability.

As a result, the hydrogen recombiner system was never tested utilizing the higher RHR pressures. Additionally, functional surveillance Procedure No. 24.409.01, " Post LOCA Thermal Recombiner Functional Test," Step No. 5.3, allowed the RHR keep-fill system to be in service to provide water to the blower and spray cooler during the test.

A temporary change to this procedure, effective December 26, 1986, deleted the use of the RHR kee)-fill system.

This is considered a violation (341/87006-02(DRP))

of 10 CFR 50, Appendix B, Criterion XI, Test Control, for failure to preoperational test and surveillance test utilizing the designed cooling water system.

On January 9, 1987, the licensee identified that while utilizing the RHR systemasasourceofcoolingwater,theDivisionIIhydrogenrecombiner system only heated up to 761 F within the required 75 minute time period.

Technical Specification 4.6.6.1 requires the outlet gas temperature to increase to greater than or equal to 1150 F within 75 minutes.

The inability to obtain the required gas temperature was due to excessive internal cooling water seal leakage at the higher RHR pressures.

As a result, the Division II hydrogen recombiner system was inoperable and unable to satisfy the surveillance requirements of Technical Specification 4.6.6.1 utilizing the designated source of cooling water.

Ever since the last seal replacement on August 29, 1985, the licensee has noticed external seal leakage with the Division II recombiner.

Therefore, the Division II hydrogen recombiner system was considered inoperable since the seal replacement on August 29, 1985.

Technical Specifications 3.6.6.1 states that "Two independent drywell and suppression chamber hydrogen recombiner systems shall be OPERABLE in Operational Conditions 1 (power operation) and 2 (startup).

Technical Specification 3.0.4 states in part, " Entry into an OPERATIONAL CONDITION or other specified condition shall not be made unless the conditions for the Limiting Condition for Operation are mb:, without reliance on provisions contained in the ACTION requirements."

During the time period from August 29, 1985, to January 8, 1987, the plant entered Operational Condition 2 (Startup) on eleven occasions (October 3, 1985, August 4, 1986, August 11, 1986, August 30, 1986, September 6, 1986, October 3, 1986, October 7, 1986, October 14, 1986, October 19, 1986, October 29, 1986, and December 19,1986) with both divisions of hydrogen recombiner systems inoperable.

This is considered a violation of Technical Specifications 3.0.4 (341/87006-03(DRP)).

r L.... g During the troubleshooting effort to repair the thermal recombiners, several problems were encountered which caused concern as to the reliability of the recombiners.

They are as follows:

Division I heater breaker would not close in on several occasions due to sticky door interlock.

Division I silicon controlled rectifiers (SCRs) failed to fire.

• Division I SCRs fired continuously"fied as broken.

• Division I pin connector was identi

Division II solenoid contact did not close in allowing closure at

heater breaker motor.

In order to address these concerns, the licensee has embarked upon a program to ensure reliability of the thermal recombiners.

This program consists of performing reliability runs in addition to the six-montfi Technical Specification surveillance requirements.

In these runs the heaters will be energized to approximately 400 F to ensure reliability of the heaters, blowers, cooling water, and electrical circuits.

These runs will be performed:

for one month, and then (3) y other day for one week; (2) once per week (1) everonce per month for six months.

If these runs are determined to be successful, the surveillance frequency will be returned to the six-month Technical Specification required frequency.

3.

Exit Interview (30703)

The inspectors met with licensee representatives (denoted in Paragraph 1)

on January 15, 1987, February 3, 1987, and informally throughout the activities. period and summarized the scope and findings of the inspection inspection The inspectors also discussed the likely informational content of the inspection report with regard to documents or processes reviewed by the inspectors during the inspection.

The. licensee did not identify any such documents / processes as pro The licensee acknowledged the findings of the inspection.prietary.

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