HBL-97-001, Submits Annual Rept of Changes,Tests & Experiments for Humboldt Bay Power Plant,Unit 3 for Reporting Interval Jan-Dec 1995

Submits Annual Rept of Changes,Tests & Experiments for Humboldt Bay Power Plant,Unit 3 for Reporting Interval Jan-Dec 1995

ML20134E424
Person / Time
Site:	Humboldt Bay
Issue date:	01/28/1997
From:	Rueger G PACIFIC GAS & ELECTRIC CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
HBL-97-001, HBL-97-1, NUDOCS 9702060215
Download: ML20134E424 (7)

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Pacific Gas and Electric Company 245 Market Street. Room 937-N98 Gregory M. Rueger San Francisco, CA 94105 Senor Vice President and

, .itailing .tu,ns GeneralManager Mail Code N9B Nuclear Power Generation P.O. Box 770000 San Francisco, CA 94177 415/973 4681 Fax 415/973-2313 January 28,1997 PG&E Letter HBL-97-001 i 1

U.S. Nuclear Regulatory Commission ATTN: Document Control Desk j Washington, D.C. 20555 l Docket No. 50-133, OL-DPR-7 Humboldt Bay Power Plant, Unit 3 10 CFR 50.59 Annual Report of Chances. Tests. and Exoeriments for the Reportina Interval January 1 Throuah December 31.1995 Dear Commissioners and Staff; Pursuant to 10 CFR 50.59, enclosed is the Annual Report of Changes, Tests,  :

and Experiments for Humboldt Bay Power Plant, Unit 3 (HBPP) for the reporting interval January 1 to December 31,1995.

Chanoes in the Facility as Described in the SAFSTOR Decommissionino Plan (SSDP)

The annual report provides a brief description of the 10 CFR 50.59 facility design change, including a summary of the safety evaluation. The change was -

reviewed and accepted by the Plant Staff Review Committee (PSRC). N Chances in Procedures as Described in the SSDP )

The annual report provides a brief description of the 10 CFR 50.59 procedure changes, including a summary of each safety evaluation. Each change was reviewed and accepted by the PSRC.

Tests and Experiments Not Described in the SSDP 1

No tests or experiments were performed during the reporting period that are not described in the SSDP.

050065 9702060215 970128 ADOCK 05000133

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U. S, Nucidar Regulatory Commission January 28,1997

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The PSRC determined that the design and procedure changes did not involve an unreviewed safety question or require a change to the HBPP Technical Specifications.

Sincerely, l 4

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i AW Mr Gregory M. Rueger cc: L. J. Callan Richard F. Dudley Michael T. Masnik Kenneth E. Perkins Humboldt Distribution Enclosure DDS/1392

. PG&E Lctter HBL-97-001 i

ENCLOSURE 10 CFR 50.59 ANNUAL REPORT OF CHANGES, TESTS, AND EXPERIMENTS l FOR THE REPORTING INTERVAL JANUARY 1 THROUGH DECEMBER 31,1995 l

HUMBOLDT BAY POWER PLANT, UNIT 3 l DOCKET NO. 50-133 1 1995 FACILITY CHANGES Listed below is the change made to Humboldt Bay Power Plant (HBPP), Unit 3 in 1995, along with a brief description of the change and a summary of the safety evaluation.

More complete records of this design change have been reviewed by the HBPP Plant Staff Review Committee (PSRC), and the change was determined not to involve an unreviewed safety question or a change to the HBPP Technical Specifications.

1. DCP P-00381 DCN HB3-EP-381 Elimination of Fuel Pit Drain Line to Core Sorav Pumo Suction This modification decreased the possibility of draining the spent fuel pool (SFP) by decreasing the length of piping that could rupture and by increasing the seismic margins of the pipe. i This modification cut and removed a section of the SFP drain pipe just ,

downstream of the first-off valve through the wall penetration and into the access shaft before the pipe chase. A blind flange was installed where the pipe was cut downstream of the valve. The remaining pipe in the access shaft was abandoned in place and may be subsequently removed.

Safety Evaluation Summary:

The SFP drain line DCN included a procedure that provided guidance on the manner to perform the modification. There are three barriers on the SFP drain line that prevent draining the pool: a first-off valve, a second-off valve, and a blank flange. The DCN procedure provided a removal / opening sequence for these barriers that ensured the SFP was not inadvertently drained when making this modification. In addition, a temporary procedure was created and approved by the PSRC that required installation of a drainable blank (blank with a 1/2-in, valve and drain path to a container and then to the reactor equipment drain tank (REDT) sump) that provided a controllable drain path in the event there was SFP water in the drain piping.

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• There was a small possibility that there was SFP water downstream of the SFP l

, first-off valve due to valve leakage. The temporary procedure ensured that any l i such water could be measured and drained in a controlled manner. Further, it  !

ensured that if a vacuum were maintaining a slug of water in the vertical run of  !

SFP piping to -66 ft, drainage of the slug could be controlled when the pipe was i breached at -13 ft and the vacuum broken. This was considered necessary l because of the unknown condition of any hot particles that might be present in }

the drain piping. l i

The DCN and the associated temporary procedure ensured that any SFP l leakage past the drain line first-off valve could be identified and controlled so as to prevent any possibility of draining the SFP. The boral cans were not affected by this modification, either during the actual modification procedure or i subsequent to the work j l

i 1995 PROCEDURE CHANGES  !

Listed below are the changes made to procedures or new procedures in 1995 as  !

described in the SAFSTOR Decommissioning Plan, along with a brief description of the i changes and a summary of the safety evaluations. More complete records of these  ;

procedure changes have been reviewed by the HBPP PSRC, and the changes were j determined not to involve an unreviewed safety question or require a change to the j HBPP Technical Specifications. l

1. TP 8/7/95 Elimination of Fuel Pit Drain Line to Core Sorav Pumo Suction This procedure implemented the modification described and authorized by DCN HB3-EP-381, Elimination of Fuel Pit Drain Line to Core Spray Pump Suction. As described in the preceding section of this report, this modification decreased the possibility of draining the SFP by decreasing the length of piping that could rupture and by increasing the seismic margins of the pipe. The preceding section of this report also summarizes the procedure used to eliminate the fuel pit drain line to core spray pump suction.

Safety Evaluation Summary:

There are three barriers on the SFP drain line that prevent draining the pool: a first-off valve , a second-off valve, and a blank flange. The procedure provided a removal / opening sequence for these barriers which ensured that the SFP was not inadvertently drained when making this modification. The procedure required installation of a drainable blank (blank with a 1/2-in. valve and drain i

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l path to a container and then to the REDT sump) that provided a controllable drain path in the event there was SFP water in the drain piping.

There was a small possibility that there was SFP water downstream of the SFP first-off valve due to valve leakage. The procedure ensured that any such water could be measured and drained in a controlled manner. Further, it ensured that if a vacuum were maintaining a slug of water in the vertical run of SFP piping to

--66 ft, drainage of the slug could be controlled when the pipe was breached at

-13 ft and the vacuum broken. This was considered necessary because of the l unknown condition of any hot particles that might be present in the drain piping.

The procedure ensured that any SFP leakage past the drain line first-off valve could be identified and controlled so as to prevent any possibility of draining the SFP. The boral cans were not affected by this modification, either during the actual modification procedure or subsequent to the work.

2. TP 11/10/95 #1 Emeraency Power for Power Panel No.1 Durina Extended Loss of Normal AC Source i This temporary procedure was written as an interim measure to provide i instructions for supplying power to Power Panel No.1 from the emergency section of MCC-10 if the normal AC power source was lost for an extended period of time. This procedure was never implemented, and it was subsequently canceled after implementation of DCN HB3-SE-383 (3/8/96), which permanently modified the power source to Power Panel No.1.

Safety Evaluation Summary:

Issue 1: Postulated failure or malfunction of Power Panel No.1 due to the ,

change in supply from Breaker 52-1012 in the normal section of MCC-10 to I Breaker 52-1027 in the emergency section of MCC-10. l i

Discussion: The basic source of power to Power Panel Nc.1 will not be i '

changed, as it will normally be supplied from the 60-kV bus through House Transformer No. 2 and Load Center Transformer No. 5, which powers both the norms and emergency sections of MCC-10. There is nothing electrically different about the power supplied from the emergency section of MCC-10 than that supplied from the normal section of MCC-10 that would result in the failure of Power Panel No.1 or any of its loads. The only change will be the ability to provide power from alternate sources in the event of an extended loss of AC power to Unit 3.

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I Issue 2: Postulated failure or malfunction of the emergency section of MCC-10 l or the loads that it normally supplies due to the addition of Power Panel No.1 to i Breaker 52-1027 in the emergency section of MCC-10.  ;

Discussion The addition of Power Panel No.1 and its associated loads are well within the design rating of the emergency section of MCC-10, since many of the j loads that it was originally designed to power were disconnected in preparation j for the SAFSTOR period, as they were no longer needed.  ;

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i 3. TP 11/10/95 #2 . Decontamination of the Reactor Caisson Sumo  !

This temporary procedure provided instructions for decontaminating the reactor l' caisson sump to allow the caisson sump to be discharged directly to the outfall canal. In addition, this procedure provided instructions for removing mineral l deposits from the 32 drain holes into the reactor caisson sump. Removal of these deposits was conducted in a controlled manner to avoid the possibility of ,

l increased flows that may have resulted in exceeding the processing capability of  ;

the liquid radwaste system. After removal of the mineral deposits, each drain .;

hole was allowed to flow freely for several minutes to flush any contaminants ,

that may have been trapped between the drain rock layer and the plugged hole.  !

1 Safety Evaluation Summary.

• l Issue 1: Postulated increased flow of groundwater exceeding the capacity of the radwaste processing system due to restoration of the number and size of the drain holes into the caisson sump.

Discussion: To fully ensure that the flow of groundwater pumped from the caisson sump does not exceed the capacity of the radwaste processing system, the procedure carefully controls the evolution of unplugging the sump influent holes, thereby limiting the groundwater flow to 3.5 gpm.

Issue 2: The potential for contamination of the caisson sump water and subsequent uncontrolled release of radioactive liquid to the environment.

Discussion: The discharge of the caisson sump pump will remain routed to the '

radwaste collection tanks. The water will be suspected of being contaminated, l in accordance with Technical Specification VI.A.1, until this procedure has been successfully completed and the sump water has been proven to be uncontaminated. While the decontamination procedure is being performed, the temporary pump will be routed to the REDT, which is then routed to the radwaste I collection tanks, thus precluding the uncontrolled release of radioactive liquid to l the environment.

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l Issue 3: The potential for total flooding of the caisson due to an uncontrolled j influx of groundwater into the caisson from a rupture of the floor due to plugging -

of allinfluent sump holes and subsequent isolation of the sump.

l Discussion: The procedure very carefully controls evolutions that could possibly  ;

l cause this type of an event, since existing flow into the sump is maintained by l i the procedure at all times. ,

The remainder of the plant-specific admin!:,irative and technical procedure revisions completed during the reportirg period did not require a written safety evaluation as j l described in 10 CFR 50.59.

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1995 TESTS AND EXPERIMF,N_T1 ,

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No tests or experiments were performed during the reporting period that are not  !

described in the SAFSTOR Decommissioning Plan. 1 l

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