ML18096A237

LER 91-011-00:on 910730,discovered That Nonradioactive Liquid Waste Discharge Radiation Monitoring Sys Channel Setpoint Not Correct.Caused by Inadequate Design Review. Design Change Process Procedure revised.W/910828 Ltr

ML18096A237
Person / Time
Site:	Salem
Issue date:	08/28/1991
From:	Pollack M, Vondra C Public Service Enterprise Group
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-91-011-02, LER-91-11-2, NUDOCS 9109050228
Download: ML18096A237 (6)

Text

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

Dear Sir:

SALEM GENERATING STATION LICENSE NO. DPR-75 DOCKET NO. 50-311 UNIT NO. 2 LICENSEE EVENT REPORT 91-011-00 August 28, 1991 This Licensee Event Report is being submitted pursuant to the requirements of the Code of Federal Regulations lOCFR 50.73(a) (2) (i) (B). This report is required within thirty (30) days of discovery.

MJP :pc* Distribution 910828 A[10CK 05000272 ' -PDR Sincerely yours, C. A. Vondra General Manager -Salem Operations

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NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED OMB NO. 3150-0104 (6-89) e -EXPIRES: 4/30/92 ES1. TED BURDEN PER RESPONSE TO COMPLY WTH THIS LICENSEE EVENT REPORT (LERI INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENT BRANCH (P-530), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104).

OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503. FACILITY NAME (1) I DOCKET NUMBER (21 I PAGE (3) Salem Generating Station o 15 Io 1oIo12 I 712 1 OF 0 15 TITLE (4) Non Rad Waste RMS Channel Setpoint Incorrect; Tech. Spec. Noncompliance EVENT DATE (5) LER NUMBER (6) REPORT DATE (7) .OTHER FACILITIES INVOLVED (Bl MONTH DAV VEAR VEAR SEQUENTIAL

?/ REVISION MONTH DAY YEAR FACILITY NAMES DOCKET NUMBER(SI NUMBER NUMBER 0151010101 I I 011 310 9 1 9 I 1 -o I i I i -ojo oja 2/ 8 9 I 1 0151010101 I I OPERATING THIS REPORT IS SUBMITTED TO THE OF 10 CFR §: (Check one_ or more of the following)

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(1 )(v) 60.73(1)(2)(iii) 50.73(1)(2Hxl LICENSEE CONTACT FOR THIS LER (12) NAME TELEPHONE NUMBER AREA CODE M. J. Pollack -LER Coordinator 610 19 3 13 I 91-I 21012 I 2 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (131 f;;::::;::::::

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SUPPLEMENTAL REPORT EXPECTED (141 MONTH DAY YEAR EXPECTED SUBMISSION n YES (ff yes, complete EXPECTED ;UBMISSION DATE) DATE (151 l I I NO ABSTRACT (Umit to 1400 spsces, i.e .. approximately fifteen single-space typewritten lines) 116} On 7/30/91, during normal plant operation, it was discovered that the Non Radioactive Liquid Waste Discharge Radiation Monitoring System (RMS) channel (2R37l setpoint was not correct contrary to the requirements of Tech. Spec. 3.3.3.8. The 2R37 channel alarm/warning setpoints did not incorporate the maximum Clearwell Pump flowrate.

In June 1985, the Non-:--Radioactive Liquid Waste Disposal system was upgraded with the implementation of desi*gn modifications.

The modification included replacement of the Clearwell Pumps with higher capacity pumps. The setpoint was not modified in June 1985 to address the increased flowrate; therefore, the 2R37 channel has been technically inoperable due to the incorrect setpoints since that time. Tech. Spec. Table 3.3-12 Action 31 requirements were not implemented until discovery of the concern on 7/30/91. The root cause of this event is inadequate design review. The 1983/84 design change review/approval failed to fully assess'the affect on the 2R37 channel setpoints.

A review determined that since 1985, a release in excess of limits is highly unlikely.

The ODCM has recently been validated by Radiation Protection/Chemistry Services.

No other RMS channel setpoint concerns associated with system design modifications are evident other that the event discussed in LER 272/90-032-00.

A design change*, to modify the 2R37 channel setpoint, has been completed.

The design change process administrative procedure will be revised to require assessment of the impact of a design change on the ODCM. NRC Form 366 (6-89)

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station Unit 2 DOCKET NUMBER 5000311 PLANT AND SYSTEM IDENTIFICATION:

Westinghouse Pressurized Water Reactor LER NUMBER 91-011-00.

PAGE 2 of 5 Energy Industry Identification codes are identified in the text as (xxJ IDENTIFICATION OF OCCURRENCE:

Non Radioactive Waste Discharge radiation monitoring channel setpoint incorrect due to inadequate design review Discovery Date: 7/30/91 Event Date: 6/1/85 Report Date: 8/28/91 This report was initiated Incident Report No.91-523. CONDITIONS PRIOR TO OCCURRENCE:

Mode 1 Reactor Power 100% -Unit Load 1120 MWe DESCRIPTION OF OCCURRENCE:

On July 30, 1991, at 0800 hours0.00926 days <br />0.222 hours <br />0.00132 weeks <br />3.044e-4 months <br />, during normal plant operation, it was discovered, by Radiation Protection/Chemistry (RP/C) Services personnel, that the Non Radioactive Liquid Waste Discharge Radiation Monitoring System (RMS) {ILi channel (2R37) setpoint was not correct. RP/C Services personnel were in the process of validating RMS channel as detailed in the Offsite Dose talculation Manual (ODCM)*. This validation was being conducted per a commitment made in LER 272/90-032-00.

The 2R37 channel alarm and warning setpoints incorporate the maximum Clearwell Pump flowrate.

In June 1985, the Non-Radioactive Liquid Waste Disposal system was upgraded with the implementation of design modifications.

As part of these modifications, the Clearwell Pumps were replaced with higher capacity pumps. The maximum pump flowrate increased from approximately 300 gpm to 1200 gpm. The ODCM identifies the setpoint as per Technical Specification 3.3.3.8. The setpoint was not modified in.June 1985 to address the increased flowrate; therefore, the 2R37 channel has been technically inoperable due to incorrect alarm/warning setpoints since that time. Since this situation was not recognized until now, Technical Specification Table 3.3-12 Action 31 requirements were not implemented (until it was discovered on July 30, 1991. Technical Specification 3.3.3.8 states: "The radioactive liquid effluent monitoring instrumentation channels shown in Table 3. 3-12 shall be OPERABLE wi.th their I I LICENSEE EVENT REPORT (LER)

CONTINUATION Salem Generating Station Unit 2 DESCRIPTION OF OCCURRENCE:

DOCKET NUMBER 5000311 (cont'd) LER NUMBER 91-011-00 PAGE 3 of 5 alarm/trip setpoints set to ensure that -the limits of. Specification 3 .. 11.1.1 are not exceeded.

The alarm/trip . setpoints of *these channels shall be determined in accor.dance with the OFFSITE DOSE CALCULATION MANUAL (ODCM)." Technical.

Specification Table Action 31-states: "With the number of channels OPERABLE less than required*

by the Minimum Channels OPERABLE.requirement, effluent releases via this pathway may continue provided that sampling is conducted in accordance.with the following table: . Frequency 1/week 1/day APPARENT CAUSE OF OCCURRENCE:

Condition During normal operation (ail MODES) During operation with an ied primary to secondary leak on either Salem Unit." The root cause of this event is inadequate design review. The Non-Radioactive Liquid Waste Disposal system design modification was completed in*June 1985. The design change packages were approved for implementation in 1983/84. The design change review/approval pr6cess failed to fully assess the affect, of the planned modification, on the 2R37 channel alarm/warning The current design change review/approval process is more thorough and requires more extensive detailed documentation.

With today's process, any RMS channel possibly affected by the design change would have its alarm/warning setpoints challenged and detailed documentation would be required for design change approval as to the reasons for setpoint modification or no setpoint modification.

ANALYSIS OF OCCURRENCE:

The 2R37 channel monitors liquid waste from the chemical waste basin prior to being released to the environment via the Circulating Water System {NNI. It ensures that releases do not contain radioactive concentrations in excess of 10CFR20, Appendix B, Table II, Column 2 limits. This monitor has read-outs locally and remotely (in the Control Room) . It has alarm/warning functions but no features.

A poteritial source of radioactive contamination in the liquid is Steam Generator (S/G) Blowdown effluent.

Contamination of the S/G blowdown occurs during periods of primary to sec6ndary leakage. Most of the soluble and particulate fission and activation products, which do leak into the S/Gs, exit the S/G via S/G blowdown.

Because both

,.J I LICENSEE EVENT REPORT {LER) TEXT CONTINUATION Salem Generating Station Unit 2 DOCKET NUMBER 5000311" LER NUMBER -*91-011-00 PAGE 4 of 5 *ANALYSIS OF OCCURRENCE:

{cont'd) Salem units operate a blowdown recovery system, these radioactive materials will accumulate on the condensate polisher resins during normal plant operations.

The release pathway is then via disposal of condensate regeneration wastes which are normally discharged to the Delaware river via the Non Radwaste Basin. S/G Blowdown may also be directly routed to the Non Radwaste Basin during special operations

{such as draining of the S/Gs during outages).

If S/G Blowdown is directly routed to the Non Radwaste Basin, RMS channels will be used to corrobora.te the 2R37 RMS channel. R19 channels alarm setpoint is int.erlocked to. cause blowdown isolation in the event of an alarm. the R19 The In the event of primary to secondary leakage, release permits are generated in accordance with the Salem ODCM. The ODCM allows these release permits to be based on either actual Non Radwaste Basin sample analysis or SIG sample analysis.

Historically, Salem has generated release permits based on S/G sample analysis.

This is more conservative no allowance is made the decay 6£ shorter lived nuclides.

• A detailed review was completed to determine if the setpoint inadequacy allowed a release of tadioactive material greater than the 10CFR20 requirements.

It was found that such a release, exceeding the 10CFR20 requirements, is highly unlikely.

The channel default alarm/warning setpoints are based on the maximum basin release flowrate.

However, the maximum recorded flowrate since 1985 is 715 gpm. In addition, the average.recorded flowrate per month was*less _than 528 gpm. Based on the 715 gpm flowrate (and not 1200 gpm) the alarm setpoint could have been set to 6830 cpm and still met the criteria.

Although this value is less than -the 10,000 cpm actually set, it is greater than the warning of 5500 cpm. A review of various station logs revealed that the highest monitor response documented was 810 cpm. Also, no record of a warning alarm was found. Based on the log data and no warning alarms, the incorrect setpoint most likely did not result in a release above the applicable limits thereby not affecting the health and safety of the public. As stated above, the alarm was not conservatively in accordance with the limitations of Technical Specification 3.3.3.8. Therefore this event is reportable to the Nuclear Regulatory Commission in accordance with Code of Federal Regulations lOCFR 50.73(a) (2) (i) (B). CORRECTIVE ACTION: A detailed review was conducted to determine if an release had occurred since 1985 in excess of what would have been allowed by the correct alarm setpoint.

As discussed in the Analysis .of Occurrence section, such a release is highly unlikely.

As stated previously, ODCM validation was required by Salem Unit 1 I LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station . Unit 2 CORRECTIVE ACTION: (cont'd) *DOCKET NUMBER 5000311 LER NUMBER 91-011-00 PAGE 5 *of 5 LER 272/90-032-00

• . The first phase of the* validation process, .which included a detailed review by Radiation Protection/Chemistry Services of setpoint calculations, has been completed.

No other RMS channel setpoint concerns associated with system design modifications evident; although, various.open items are awaiting evaluation by Engineering.

The design change review/approval process enhancements made since 1983/84, provide greater assurance that the ODCM is reviewed for design impact. -Although these enhancements include .better documentation of design change package reviews and more detailed documentation of safety considerations, they do not guarantee ODCM review. Therefore, the design change process administrative procedure will be revised to require assessment of the impact of a design change on the ODCM. A design change was implemented to modify the 2R37 channel setpoint.

Technical Table 3.3-12.Action 31 was exited on August 28, 1991 at 1220 hours0.0141 days <br />0.339 hours <br />0.00202 weeks <br />4.6421e-4 months <br />. MJP:pc SORC Mtg.91-088 General Manager -Salem Operations