ML20244D582

Recommends That Consideration Be Given to Revising Tech Spec Limiting Condition for Operation Following Failure of Control Room Cooling for All Plants W/Solid State Reactor Protection Sys Subj to High Temp Malfunctions

ML20244D582
Person / Time
Site:	Mcguire, McGuire, 05000000
Issue date:	12/04/1985
From:	Jordan E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
To:	Russell W Office of Nuclear Reactor Regulation
Shared Package
ML16342B348	List: IA-87-121, Discusses Inservice Test Programs Re Full Stroke Exercising of Normally Closed Swing or Tilting Disk Check Valves Per 10CFR50.55a & Section XI of ASME Code ML20235B266 ML20235B268 ML20235B295 ML20235B304 ML20235B322 ML20235B406 ML20235B470 ML20235B514 ML20235B581 ML20235B613 ML20235B673 ML20235B768 ML20235B785 ML20235B799 ML20235B859 ML20235B877 ML20235B922 ML20235C007 ML20235C967 ML20235C970 ML20235D014 ML20235D041 ML20235D091 ML20235D157 ML20235D188 ML20235D233 ML20235D400 ML20235D433 ML20235D484 ML20235D532 ML20244B491 ML20244B568 ML20244B571 ML20244B913 ML20244B937 ML20244B941 ML20244B943 ML20244C126 ML20244C271 ML20244C361 ML20244C777 ML20244C785 ML20244C833 ML20244C935 ML20244C940 ML20244C986 ML20244D413 ML20244D552 ML20244D582 ... further results
References
FOIA-87-121 IEIN-85-089, IEIN-85-89, NUDOCS 8512100530
Download: ML20244D582 (2)

Text

,

,- r .

w UNITED STATES (l. l0 4

/ NUCLEAR REGULATORY COMMISSION pg3 g,3 7, ,3g,y r ]

g " M h 0*

A e first s  !

~~

m .11.f_

7=

OL MA 91 g 4 95 . m /

fnu MEMORANDUM FOR: William T. Russell, Director Division of Human Factors Technology Office of Nuclear Reactor Regulation FROM: Edward L. Jordan, Director Division of Emergency Preparedness and Engineering Response Office of Inspection and Enforcement

SUBJECT:

RECOMMENDED TECHNICAL SPECIFICATION CHANGE CONCERNING THE LOSS OF CONTROL ROOM COOLING Region 11 recently advised IE of a problem of the loss of all control room cooling and the subsequent erratic instrumentation output resulting from overheating of Westinghouse PCS 7300 cabinets and associated solid state protection system .at McGuire Station on June 4,1984. IE Information Notice 85-89, " Potential Loss of Solid-State Instrumentation Following Failure of Control Room Cooling," was prepared based on a draft provided by Region 11 and was issued on November 19, 1985. Based on our review, we believe this is a significant safety concern that warrants consideration for technical specifi-cation changes in addition to the inform: tion notice. AE0D is also reviewing this event and will issue their recommendations, if any, separately.

The McGuire incident demonstrated that the solid Atate protection system will provide spurious signals shortly after the loss of HVAC allows ambient tempera-ture to rise. We believe that unless action is taken, as it was at McGuire to '

provide alternate cooling to the solid state equipment, the loss of instrumen-tation likely would be significant during the 7 hour8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> period allowed by current technical specification to achieve hot standby. McGuire had reduced power to 97 percent 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after the loss of all control room cooling. They had numerous spurious alarms 45 minutes after the HVAC failure and before plant shutdown was initiated. The alternate cooling action and the recovery of one of the HVAC units prevented further problems at McGuire. Because the overheat-ing problem is common to many systems within the solid state cabinets, there could also be a reactor trip or other unexpected control system actuations at the same time that instrumentation is unavailable or is providing erratic .

information. McGuire has taken action to reduce the susceptability of solid state cabinets to overheating during normal operation, but we believe that the total failure of control room HVAC would still result in significant loss of instrumentation before the plant achieves hot standby.

Technical

Contact:

James Stewart, IE 1 (301)492-9061 {

ssscuoo63o DEC 61985 mze e

l

,o William T. Russell Based on the above information we recomend that consideration be given to  !

revising technical specifications limiting conditions for operation following failure of control room cooling for all plants with solid state reactor protec-tion systems subject to high te.nperature malfunctions. We believe that more stringent requirements to require a fast shutdown to hot standby or demonstrate the availability of enough alternate cooling to maintain acceptable operating temperature would serve two purposes. First, it would provide greater induce-ment for utilities to correct known unreliable HVAC units. Secondly, it would help to ensure that the plant is stable prior to the expected loss of instrumentation.

For your use in evaluating this suggested technical specification change, we note that, in addition to the loss of coolers at McGuire, there has been recent identification of possible HVAC comon failure modes at Browns Ferry and Limerick which could indicate that the potential failure of redundant HVAC  :

units is greater than previously expected.

b41nal signed sy:

E. O Jordan Edward L. Jordan, Director Division of Emergency Preparedness and Engineering Response Office of Inspection and Enforcement DISTRIBUTION JMTaylor RHVollmer ELJordan SASchwartz RLBaer AWDromerick JStewart JGPartlow BKGrimes GGZech ERossi RWStarostecki, RI JNGrace, RII RDWalker, RII CENorelius, RIII HCDance, RII EHJohnson, RIV DFKirsch, RV CHeltemes, AE0D MChirimal, AE0D EWBrach, EDO HLThompson, NRR FJMMiraglia, NRR RMBernero, NRR GHolahan, NRR EJButcher, NRR DCS DEPER R/F EGCB R/F JStewart R/F

• See previous concurrences

• DEPER:IE *DEPER:IE *DEPER:IE jDEPER:IE .IE JStewart AWDromerick RLBaer SASchwartz LJordan 11/15/85 11/19/85 11/21/85 11/ /85 g/p/85