GO2-82-945, Interim Deficiency Rept Re Controls for Remote Shutdown Panel & Pump Discharge Switch.Initially Reported on 820819 & 0820,respectively.Switches & Valves Will Be Relocated.Next Rept Will Be Submitted on 830228

Interim Deficiency Rept Re Controls for Remote Shutdown Panel & Pump Discharge Switch.Initially Reported on 820819 & 0820,respectively.Switches & Valves Will Be Relocated.Next Rept Will Be Submitted on 830228

ML20067B718
Person / Time
Site:	Columbia
Issue date:	11/23/1982
From:	Matlock R WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:	Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
References
10CFR-050.55E, 10CFR-50.55E, GO2-82-945, NUDOCS 8212060289
Download: ML20067B718 (4)

Text

r Docket No. 50-397 p.*

50. 55 (e) Report Q N@ O Washington Public Power Supply Systeroff P.O. Box 968 3000 GeorgeWashingtonWay Richland, Washington 99352 hy2-5000 Docket No. 50-397 /

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November 23, 1982 UC:og %

G02-82-945 Mr. R. H. Engelken Regional Administrator U.S. Nuclear Regulatory Commission 1450 Maria Lane, Suite 210 Walnut Creek, California 94596

Subject:

NUCLEAR PROJECT NO. 2 10CFR50.55(e) REPORTABLE CONDITIONS #208 - REMOTE SHUTDOWN PANEL AND #209 - PUMP DISCHARGE PRESSURE SWITCH In accordance with the provisions of 10CFR50.55(e), your office was informed, by telephone, of the above subject conditions on August 19, 1982 and August 20, 1982, respectively. Attachments A and B provide the Project's interim reports on these conditions. We will continue to provide your office with quarterly updates on the subject conditions until such time as they are resolved. The next report will be submitted on or before February 28, g .

If there are any questions, please contact Roger Johnson, Project QA Manager, WNP-2, at (509) 377-2501, extension 2712.

/je 1 Program Director, WNP-2 MER/kd Attachments: A. Interim Report - 10CFR50.55(e) #208 B. Interim Report - 10CFR50.55(e) #209 cc: W.S. Chin, BPA A. Forrest, Burns and Roe - HAPO N.D. Lewis, NRC J. Plunkett, NUS Corp.

R.E. Snaith, Burns and Roe - NY A. Toth, NRC Resident Inspector - 917Q Document Control, NRC WNP-2 Files (917B) jk2gg{fo$$oo

, t E' ATTACIMENT A WASHINGTON PUBLIC POWER SUPPLY SYSTEM NUCLEAR PROJECT NO. 2 DOCKET NO. 50-397 LICENSE NO. CPPR-93 REMOTE SHUTDOWN PANEL 10CFR50.55(e) #208 INTERIM REPORT Description of Deficiency GE design criteria (22A3085, Sec. 4.1) states that "the remote shutdown system shall be designed to control the required shutdown systems from outside the control room irrespective of shorts, opens, or grounds in control circuits (in the control room)" which we have committed to in the FSAR (Sec. 7.4.1.4.b).

The remote shutdown panel controls loop B of the standby service water (SSW). During a Human Factors Engineering Review, it was discovered that there did not exist any controls on the remote shutdown panel to operate valve SW-PCV-38B. During a subsequent review, it was further discovered that the Supervisory Control Panel CS-2, which controls valves SW-V-2B, SW-V-128 and SW-V-698, received its power from the con-trol room.

Analysis of Safety Implication If the control room is evacuated and it becomes necessary to bring the reactor to cold shutdown, the spray ponds may not be available. Reactor decay heat would be dumped to the suppression pool which ultimately would lead to overpressurization of the primary containment.

Corrective Action The design of the remote shutdown panel has been reviewed and no other deficiencies have been identified. Control switches for SW-PCV-38B will be located on the remote shutdown panel and power to the supervi-sory panel will be supplied from outside c;1e control room. Project Engineering Directives (PED's) will be issued for the required modifica-tions by December 1, 1982.

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ATTACIMENT B WASHINGTON PUBLIC POWER SUPPLY SYSTEM NUCLEAR PROJECT NO. 2 DOCKET NO. 50-397 LICENSE NO. CPPR-93 RHR PUMP DISCHARGE PRESSURE SWITCH 10CFR50.55(e) CONDITION #209 INTERIM REPORT Description of Defect On the discharge side of the Residual Heat Removal (RHR) and Low Pressure Core Spray (LPCS) pumps are redundant pressure switches (RHR-PS-16A, B & C, RHR-PS-19A, B & C, LCS-PS-1 and LPCS-PS-9) with nominal setpoints of 100 psig for RHR 150 psig for LPCS. Their function is to "tell" the Automatic Depressurization System (ADS) that the low pressure ECC5 pumps are running. This permissive is needed before the ADS depressurizes the reactcr vessel in a post-LOCA situation. On the discharge side of the HPCS pump is pressure switch HPCS-PS-12 with a nominal set-point of 120 psig. Its function is to "tell" the HPCS minimum flow valve, HPCS-V-12, that the HPCS pump is running. This signal, in series with a low flow signal from HPCS-FIS-6, will open the minimum flow valve. The present installed locations for all these pressure switches may subject them to water hammer and disable them such that they cannot meet their safety function.

These pressure switches all have sensing points upstream of their respective pump discharge check valves at about El. 422'. During normal plant operation, with the ECCS pumps in standby mode (not running), they will "see" the static head of the suppression pool, whose minimum elevation is 466' - 0 3/4". All the pressure switches are located on racks whose elevation is greater than suppression pool water level. They are as follows:

PRESSURE SWITCH INSTRUMENT RACK FLOOR ELEVATION OF RACK RHR-PS-16A H22-P018 501' RHR-PS-16B H22-P021 501' RHR-PS-16C H22-P021 501' RHR-PS-19A H22-P018 501' RHR-PS-19B H22-P021 501' RHR-PS-19C H22-P021 501' HPCS-PS-12 H22-P024 471' LPCS-PS-1 H22-P001 471' LPCS-PS-9 H22-P001 471' For the instrument racks on El. 501', the instrument tubing is approximately 250' long and runs up to El. 516' before hooking into the pressure switch at approxi-mately EL. 505' (see attached sketch). For the instrument racks on El. 471', the instrument tubing is approximately 200' long and runs up to approximately El. 490' before hooking into the pressure switch at approximately El. 475'.

During normal plant operation, the sensing lines cannot be completely filled with water because the suppression pool can only fill it to El. 466'. With an air poc-ket in the sensing line, the pressure switch will not actuate at the required set-point if it had been compensated for the static head difference between the sensing point and the prescure switch. This in itself is not a significant safety issue because the switch will trip early, although how early has not been determined.

It would be difficult to accurately compensate for the air pocket due to the sens-ing line's tortuous routing and intermediate high point. However, there is a poten-tial for water hammer in the sensing lines which could damage the pressure switches and not allow the ADS to function or the HPCS minimum flow valve to open.

s Interim Report - #209 Page Two Analysis of Safety Implications -

If water hammer disables the pressure switches, then a substantial safety hazard could be created during a small break LOCA scenario. Using design basis accident assumptions, the HPCS is assumed to fail after a small break. The reactor remains pressurized so that the low pressure systems (RHR and LPCS) cannot inject. At reactor water Level 1 (just above the active fuel), the ADS two-minute timer is started and waits for water level to recover. Because HPCS is assumed to fail, water level continues to drop until the timer times out. The ADS logic then veri-fies that the RHR and LPCS pumps are running before it depressurizes the reactor.

If the pressure switches are disabled at the start of the accident due to water hammer during pump start, no verification will occur and the reactor will not auto-matically depressurize. Manual depressurization can still occur, but using design basis accident assumptions, it cannot be taken credit for at least 10 minutes.

With no automatic depressurization, we would be outside the safety analysis of FSAR Chapter 6 for a small break accident.

Failure of the HPCS pressure switch due to water hammer could cause a significant hazard in a small break scenario in which HPCS maintains reactor water level up to Level 8 trip. At level 8, the HPCS injection valve closes and the pump is sup-posed to go into minimum flow recirculation. However, with HPCS-PS-12 damaged and unable to verify " pump running," the minimum flow valve will not open. The HPCS pump can damage itself such that no high pressure makeup is available. Now the plant is in the same situation described in the previous paragraph.

Corrective Action The instrument sensing line root valves will be relocated to points downstream of the ECCS pump discharge line check valves. Those portions of the lines are 4 maintained under pressure by a water-leg pump. Project Engineering Directive (PED) 220-I-0950 was issued on October 27, 1982 to relocate the root valves downstream as stated above.

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