ML18095A858

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LER 91-005-01:on 910209,containment Fan Coil Units Did Not Meet Design Accident Requirements Identified by Updated Fsar.Caused by Inadequate Administrative Control.Cleaning of Inlet Side of Water Box performed.W/910402 Ltr
ML18095A858
Person / Time
Site: Salem PSEG icon.png
Issue date: 04/02/1991
From: Pollack J, Vondra C
Public Service Enterprise Group
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-91-005, LER-91-5, NUDOCS 9104100199
Download: ML18095A858 (6)
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Text

Public Service Electric and Gas Company P.O. Box 236 Hancocks Bridge, New Jersey 08038 Salem Generating Station April 2, 1991 U. S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555

Dear Sir:

SALEM GENERATING STATION LICENSE NO. DPR-70 DOCKET NO. 50-272 UNIT.NO. 1 SUPPLEMENTAL LICENSEE EVENT REPORT 91-005-01 This Licensee Event Report supplement is being submitted* pursuant to the requirements of the Code of Federal Regulations 10CFR50.73.

The root.cause of this event has been revised based upon subsequent review of this event.

Sincerely yours, C. A. Vondra General Manager Salem Operations MJP:pc Distribution 7*

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  • '-' *-* PDR ADOCK 05000272 95-2189 (10M) 12-89 S PDR

NRC Form 388 U.S. NUCLEAR REGULATORY COMMISSION 19-831 APPROVEO OMll NO. 3150,-Q104 EXPIRES: 8/31185 LICENSEE EVENT REPORT (LER)

FACILITY NAME (11 Salem Gene~ating St~~ion ~ Unit 1.

TITLE l*I Cont. Fan c'oil. Units.Do Not Meet Design Heat Removal Req.'ts. Due* To.Inad .. Admin. Controls EVENT OATE lt!I LER NUMBER (81 REPORT DATE (7) OTHER F~ILITIES INVOLVED Ill)

MONTH DAY YEAR YEAR wt se~~~~~~AL rt ~t~~~ MONTH DAY YEAR FACILITY NAMES DOCKET NUMBER!Sl Salem Unit 2 o 1s1010.10131111 oIo I s - .. o11 ol 4 o12 9 I1 0151010101 I 1.

THll REPORT Iii SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Choclc OM or mo,. of f/rl following) (11)

OPERATING POWER LEVEL I.

1 IQ I . Q t--MOO--Er!l-1_...._..;;;l+--1 20.'°2!bl 20.'°8!*H1 IUJ 20 *.ae11H1 Hiil

-- 20.olOll(cl ll0.381cll1l ll0.381cH2l t!0.73loH2Hl*l t!0.731oll2JM ll0.73loll2Hvfl) 13.111111 73.71(*1 .

OTHER (Sp<<lfy in Ab1trw:t

. 1101 .

~: J£. Nlow inti In T1xt. NRC Form 20.'°8(1)(1 )(Ill) So.73f1ll2.llll

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20.'°'5(1)(11i~1 . t!0.73l1H2Hllll ll0.73(o)(211xl LICENSEE CONTACT FOR THIS LER (12)

NAME TELEPHONE NUMBER AREA CODE M. J. Pollack - LER Coordin&tor COMPLETE ON.E LINE FOR EACH COMPONENT FAILURE DESCR!BEO IN THil REPORT 1131 MANUFAC. MANUFAC.

CAUSE SYSTEM COMPONENT TUR ER TUR ER I I I I I I I I I I I I I I I I I I I I I I. I I ( I I I

.IUPPLEMENTAL REPORT EXPECTED 11'1

  • MONTH DAY Y~AR EXPECTED

- - , YES (If~... oomptm EXPEC_TEO SUBMlsSION DATE/ rxi NO AISTAACT (Limit ro 14()(} 1Pk1t. l.1.* 1pproxim1r.ty fiftHn ~ingll-IPICI tylHJWTitton /inn} l~ll .

SUBMISSION DATE 1151 I* I I On 2/9/91 at 1945 hours0.0225 days <br />0.54 hours <br />0.00322 weeks <br />7.400725e-4 months <br />, engineering coirtpleted an analysis of thermal performance testing for Containment Fan Coil Units (CFCUs) heat removal capacity. This review concluded that 3 of the 5 CFCUs did not meet their design accident requirements as identified by the Updated Final Safety Analysis Report (UFSAR). The Nos. 12, 13.and* 14 CFCUs were not capable of heat removal at a rate of 81x106 BTU/hr each~ Also, the UFSAR accident analysis*assumption that 3 remaining CFCUs (after the*

failure of a single Vital Bus) would be capable of removing 243xl0 6 BTU/hr (at 85°F river water temper~ture) could not be met. Testing of the CFCUs, to verify th.eir heat transfer capability, was conduct.ed in ac;cordc:mce with NRC Generic Letter 89-13. It. was conducted with the*.

Unit at full power operation. The Unit.was brought to Mode 3 on 2/9/91 in support of its ninth refueling outage. The root cause of the CFCU

_loss of heat removal capacity is attributed to inadequate admin.

control. CFCU heat.capacity testing has not been required nor l.

performed since CFCU installation. Due to lack of a test program, ~~

degrading performance was not identified arid corrected. The reduction in heat removal capacity is attributed to CFCU cooling coil partial-blockage. An evaluation by Westinghouse, justifying plant operation between 1/28/91 and 2/7/91, was performed and was confirmed by PSE&G engineering. Recurring tasks have been initiated (both Salem Units) to

. test heat removal capacity of the CFCUs. The Salem U-2 CFCUs wer.e recently tested for.heat removal capacity. All 5 units exceeded UFSAR heat removal capacity design requirements. The Salem U-1 CFCUs will be cleaned during the current refueling o~tage and subsequently ~etested.

NRC Form JM IHJI"

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station DOCKET NUMBER LER NUMBER PAGE

. Unit 1 5000*272 91-005-01 2 of 5

  • PLANT AND SYSTEM IDENTlFICATION:

Westinghouse_* - . Pressurized Water Reactor Energy Industry Identificition System (EfIS) codes a~e ~de~t1fied in the text as {xxl IDENTIFICATION OF OCCURRENCE:

Containmerit.Fan*coil Units*do_not meet_design heat removal.

requirements due to equipment failure Discovery Date: 2/09/91.

Report Date: 4/02/91 This. report was initiated by Incident Report No. 91'."'"090*.

CONDITIONS PRIOR TO OCCURRENCE:

Mode 3 (Hot Standby)

DESCRIPTION OF OCCURRENCE:

On February 9, .1991 at 1945 hours0.0225 days <br />0.54 hours <br />0.00322 weeks <br />7.400725e-4 months <br />, engineering completed an analysis of thermal performance .testing for Containment Fan Coil Units (CFCUs}

. {BKI heat removal capacity. This review concluded .that three (3) of

Nos. 12, *13 and 14 CFCUs were not capable of heat removal *at* a rate of 81xl0 6 BTU/hr each. Also, the UFSAR accident analysis assumption that three (3) remaining CFCUs (after the failure of a sfngle Vital Bus) would be. capable of removing 243xl06 BTu/hr (at 85° F riv*er water temperature) could not be met. The Analysis of Occurrence Sect1on details the test results. .

Ori February 9, 1991 at 1945. hours, the Nuclear Regulatory Commission was notified of the Unit operating in a condition outside of its design base in accordance with Code of Federai Regulations 10CFR .

50. 72 (b) (1) (ii}~

Testing of the CFCUs, to verify their heat transfer capability, was conducted in accordance _with NRC Generic Letter 89-13, "Service Water System Problems Affecting Safety-Rel,ated Equipment". It was conducted with the Unit .at full power operation. Th~ Unit was brought to Mode 3 on February 9, 1991 in support- of the start of its ninth refueling outage. Generic Letter 89-13 addresses the need for testing "to verify the heat.transfer capability of all safety-related heat exchangers cooled by service water". A test program which addresses the concerns of the Generic Letter is in progress. This program is in conformance with the Generic Letter.

APPARENT CAUSE OF OCCURRENCE:

The root cause .*of the CFCU loss of heat. removal capacity is attributed

LICENSI EVENT REPORT (LER) TEXT clTINUATION Saiem Generating Station DOCKET NUMBER LER NUMBER PAGE

~U~n=i~t'-=1'--~~~~~~~~~~~~-=5000272 91-005-01 3 of 5 APPARENT CAUSE OF OCCURRENCE: (cont'd) to inadequate administrative control. CFCU testing for heat capacity has not been required nor has it been performed since installation of the CFCUs. Due to this lack of a CFCU heat remo*a1 capa6ity test program, a degrading performance trend was not identified and corrected before UFSAR limitations were reached. New CFCU cooling coils had been installed circa 1983. The reduction in heat removal capacity is attributed to CFCU cooling coil partial blockage.

Technical Specification CFCU surveillance requirements do not include testing for heat removal capability~ -

ANALYSIS OF OCCURRENCE: ,

The CFCUs are design-ed to ensure the containment air temperature is maintained within limits (i.e., 120°F) during normal operation and adequate heat removal capacity is aval.lable when operated in conjunction with the Containment Spray System during post-LOCA conditions. The design is such that with all five (~) CFCUs operable, both Containment Spray Pumps, or a combination of three (3) CFCUs and one (1) Containment Spray Pump, the resulting temperature/pressure transient within Containment, after a design base accident (e.g.,

LOCA), will be mitigated.

There are.five separate CFCUs which are broken up into three distinct groups. No. 11 CFCU is Group 1, Nos.- 12 and 14 CFCUs are Group 2, and Nos. 13 and 15 CFCUs are Group 3. If either CFCU in Groups 2 or 3 b~come inoperable, that respective Group becomes inoperable.

The results of heat transfer performance testing of the CFCUs is listed below. These values are the heat removal capacities at design accident conditions at_the Service Water temperature specified.

CFCU :fl: Date of Test Test Results Test Results at at 85° F 50°F (the current river temperature) 11 1/4/91 83.6E6 BTU/hr 99.2E6 BTU/hr 12 2/9/91 62.1E6 BTU/hr 73.7E6 BTU/hr 13 2/8/91 42.2E6 BTU/hr 50.1E6 BTU/hr 14 1/25/91 50.1E6 BTU/hr 59.3E6 BTU/hr 14 2/7/91 72.5E6 BTU/hr 86.0E6 BTU/hr 15 1/9/91 85.4E6 BTU/hr 101.1E6 BTU/hr Based upon the group arrangements of the CFCUs, the heat removal capacity of any combination of CFCUs would not be sufficient to meet the design requirement as specified by the UFSAR, at 85°F river water temperature. This requirement includes heat removal capacity of 243E6 BTU/hr from three (3) CFCUs given the failure of a Vital Bus (which in the worst case removes two (2) CFCUs from service).

No. 14 CFCU was the first CFCU tested that did not meet the minimum required heat removal requirement of 81E6 BTU/hr. An engineering review of the test results was completed on January 28, 1991. On February 2, 1991, a safety evaluation (reference Discrepancy Report DR

LICENSI EVENT REPORT (LER) TEXT' cl;INUATION Salem Generating Station DOCKET NUMBER LER NUMBER* PAGE Unit 1 5000272 91-005-0l 4 of 5 ANALYSIS OF OCCURRENCE: (cont'd)

STD-*91-0.30) .was* completed justifying continued operation of the Unit (without entry into the Technical. Specification: Action Statement for "inoperability" of a single CFCU .group). This evaluation was based on ..

the combined performance of the three ( 3) rema*ining CFCUs on the loss.

of "C" Vital Bus a:t a river temperature of .50°F meeting the design heat removal capacity requirement. It was assumed, :;in the_safety evaluation, that the No. 12 CFCU would meet the UFS,AR requirement.

on: February 8, 199l .and Februa:r;y 9, 1991, the No. 13 CFCU and No. 12 CFCU were tested, respe.ctively. Evaluation of t'.be test results showed that both .CFCUs did not meet design. These test results invalidated the safety evaruation assumption that No. 12 CFCU could meet its design requirement. *.Based upon the "group" arrangement, two groups of

  • CFCUs (i.e., Groups 2 and 3) did not meet design. Subsequently, *on February 9, 1991, Technical Specification j.6.2.3 Action "b" was

.entered backdating ifs entry to February 8, 1991. at 2006 hours0.0232 days <br />0.557 hours <br />0.00332 weeks <br />7.63283e-4 months <br /> (the date and time when No.-13 CFCU was tested). It was exited on February 10*, 1991 at 0930 hours0.0108 days <br />0.258 hours <br />0.00154 weeks <br />3.53865e-4 months <br /> with the Unit entering Mode 4 (Hot Shutdown).

Te~hnical Specification 3.6.2.3 is not applicable in Mode 4.

  • Technical Specification 3.6.2.3. states:

"Three independent groups of containment cooling fans shall* be OPERABLE with two fan systems to each *of two groups and one fan system to the third group."

Techni6al Specification 3.6.2.3 Action ~b~ stat~s:

"a. With one group of the above required containment cooling fans inoperable.and*both containment spray systems.OPERABLE, restore the inoperable group of cooling fans to OPERABLE status within 7 days or be *in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

b. With two groups of the above required containment cooling fans inoperable and both containment spray systems OPERABLE~

restore at least one group of cooling fans to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />. Restore both above required groups of cooling fans t_o OPERABLE status within 7 days of initial loss or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the fol_lowj,.ng 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />."

An Engineering Evaluation (S-1-CBV-MEE-OS38) has been prepared which

  • evaluates the safety significance of operating with degraded CFCUs between January 28, 1991 and February 7, 1991. This period covers the time between when No~ 14 CFCU first test evaluation (by Engineering) was complete and when the CFCU was retested after cleaning. This evaluation, which was based upon a Westinghouse analysis, considered the most limiting Containment pressure and temperature cases assuming

. LICEN. EVENT REPORT (LER) TEXT-,NTINUATION Salem Generating Station DOCKET NUMBER LER NUMBER PAGE Unit 1 5000272 91-005-01 *5 of 5 ANALYSIS OF OCCURRENCE: (cont'd) the failure of a single diesel generator and failure-of Auxiliary Feedwater {BA} runout protection. The evaluation concluded that *ther_e was no safety significance with the operation of the degraded CFCUs during the -subject period. Therefore, the heal th and safety of the_ -

public was not affected.

Due.to the Unit not meeting its design basis assumptions (as specified by the UFSAR), this event is reportable to the NRC in accordance with Code of Federal Regulations 10CFR 50.73(a) (2) (ii) (B). It is also reportable in accordance with 10CFR 50.73(a) (2) (vii) (D) since a single cause resulted in inoperability of three (3) CFCUs.

CORRECTIVE ACTION:

As indicated in the Analysis of Occurrence section, the No. 14 CFCU did not successfully pass its first test. Prior to continuing testing of the remaining CFCUs, cleaning of the inlet side of the water box was performed. Small amounts of debris (e.g., seaweed) was removed.

The CFCU was retested on February 7, 1991, showing significant improvement in performance. Its performance exceeded the design requirement at 50°F; however, it was still below the design requirement at 85°F. -

An evaluation by Westinghouse, justifying plant operation between January 28, 1991 and February 7, 1991 was performed. It was reviewed and confirmed by PSE&G engineering.

_Recurring tasks have been initiated (both Salem Units) to. test heat removal capacity of the CFCUs consistent with the recommendations of Generie Letter 89-13.

The Salem Unit 2 CFCUs were recently tested for heat removal capacity~ All five units exceeded UFSAR heat removal capacity design requirements.

The Salem Unit 1 CFCUs will be cleaned during the current refueling outage and subsequently retested.

General Manager -

Salem Operations MJP:pc

- SORC Mtg.91-026

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