ML20059F845

Responds to Exam Rept 50-352/93-18 & 50-353/93-18 Which Identified Weakness in Examinees Performance in Identification & Proper Action Re Core Thermal Hydraulic Instabilities

ML20059F845
Person / Time
Site:	Limerick
Issue date:	11/01/1993
From:	Helwig D PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9311050113
Download: ML20059F845 (4)

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PIIILADELPHIA ELECTRIC COMPANY l LIMERICK GENERATING STATION  !

I P. O. BOX 2300 SANATOGA, PA 19464-2300 l

i (215) 327-1200, EXT. 3000 (

i DAVID R. HELWIG November 1, 1993 .:

VICE PRESIDENT LIMERICK GENERATING STATION j Docket Nos. 50-352 i 50-353 License Nos. NPF-39 NPF-85 U.S. Nuclear Regulatory Commission I Attn: Document Control Desk l Washington, DC 20555 f i

SUBJECT:

Limerick Generating Station, Units 1 and 2 Reply to NRC Examination Report Nos. 50-352/93-18 and 50-353/93-18 i

NRC Examination Report Nos. 50-352/93-18 and 50-353/93-18 documents the results of the NRC initial operator license  !

examinations administered to certain Philadelphia Electric Company (PECo) employees. The report identified an apparent weakness in the examinees' performance in the identification and f

. proper action related to core thermal hydraulic (T-H) r instabilities. The report stated that the weak performance may [

have been due to weak procedural guidance or poor training and  ;

questioned how licensed operators will perform in the plant when  !

faced with normal versus abnormal core power oscillations. The report requested a written reply providing the actions taken or planned in response to the noted weakness by October 2, 1993.  ;

i On October 14, 1993, a meeting was conducted between PECo  !

and the NRC to discuss and clarify the concerns identified in the  !

subject NRC Examination Report. As a result of this meeting,  !

PECo committed to providing to the NRC the documentation i supporting the procedure changes related to core T-H j 4 instabilities. Supporting documentation has been made available 1 to the HRC Senior Resident Inspector for Limerick Generating Station for review. Additionally, PECo committed to providing information on how the commitments contained in PEco's reply to i Bulletin 88-07, " Power Oscillations in Boiling Water Reactors (BWRs)," Supplement 1, were evaluated as part of the changes made to the procedures.

This letter provides the requested and committed to  !

I information. This response is being submitted by November 1, 1993 as agreed upon during the October 14, 1993 meeting. hi AD V

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l U.S. Nuclear Regulatory Commission November 1, 1993 l Document Control Desk Page 2 of 3 -;

Docket 'Nos 50-352 and 50-353 In response to the apparent performance weakness and related ,

core T-H oscillation training and procedural concerns noted in  !

the subject NRC Examination Report several actions were taken l between July and September 1993.

To ensure proper current operator response, core oscillations similar to the transients run during the initial  ;

operator license exams were run during Licensed Operator l Requalification (LOR) training in July 1993. Interviews were then l conducted with many of the licensed operators to test their 1 understanding of core T-H oscillations, related symptoms, and  ;

applicable procedural guidance for responding to this type of transient, The operators demonstrated that they would recognize and [

correctly respond to abnormal core power oscillations. Through  !

performance and discussion they exhibited thorough knowledge of 4

) core T-H oscillation transients. However, the interviewed  !

operators placed low emphasis on the frequency of oscillations }

exhibited during a core T-H instability transient and exhibited  !

an incomplete awareness of strong positive or negative swings of l the reactor neutron multiplication period meter. j t

I To determine the cause of the performance weakness observed i by the NRC, interviews with the newly licensed operators were  !

conducted. Based on these interviews we have concluded that the [

Neak performance was due primarily to factors related to the  ;

examination process and not to procedural guidance or training. l However, the newly licensed operators did exhibit the same {

knowledge weakness as noted above during the LOR training. l i

To address these kncwledge weaknesses, the bases for the Operational Transient Procedures covering core T-H oscillations {

will be revised to clarify the frequency of the expected power  ;

oscillations and the expected response of the period meter. i Training on these changes will be provided in LOR training  !

scheduled to start in November 1993.

In response to the concerns expressed at the October 14, ,

1993 meeting, a review was made of the 1992 revisions to the core f

[ T-H oscillation procedures, the technical basis for the -

revisions, and of bow the original commitments made in response  :

to NRC Bulletin 88-07, Supplement 1, were evaluated. {

The procedure revisions performed in June 1992, modified the  ;

core T-H oscillation detection guidance. These revisions were  !

evaluated under 10CFR50.59 and the commitments made in response  ;

to the Bulletin Supplement were included in the evaluation. We l

} had concluded that the core T-H oscillation detection guidance }

provided in the Boiling Water Owners' Group (BWROG) letter dated l March 18, 1992, titled, " Implementation Guidance for Stability j i  ;

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U.S. Nuclear Regulatory Commission November 1, 1993 Document Control Desk Page 3 of 3  :

Docket Mos. 50-352 and 50-353 i

4 I i Interim Corrective Actions," was more restrictive than the ,

i detection guidance that had previously been committed to in our i response to tne Bulletin Supplement. This guidance was l subsequently cited in NRC Information Notice 92-74, " Power i j Oscillations at Washington Nuclear Power Unit 2," dated November 10, 1992. The indi idual that performed the 10CFR50.59 Reviews  ;

concluded incorporation of the new guidance maintained or '

j enhanced the level of safety that was established by the original  ;

1 ccmmitment. Since the procedure changes were determined to be '

, within the bounds of the original commitments and did not involve ,

l an unreviewed safety question, prior NRC notification of the j procedure changes was deemed to be not necessary. However, during the evaluation of the deviation contained in NRC Examination Report 50-352/353/92-21, we discovered that the j 10CFR50.59 Reviews for the procedure revisions did not contain ,

sufficient detail. The 10CFR50.59 Reviews were revised in December 1992, to include the details of the evaluation related to the change in core T-H oscillation detection guidance.  ;

Following the meeting conducted on October 14, 1993, the 1

procedures related to core T-H oscillations were again reviewed 1 and we have again concluded that the information in the l l procedures is still within the bounds of (i.e., more conservative  :

j than) the commitments made to the Bulletin Supplement, especially <

l for the detection of regional core T-H oscillations. However,

Lased on a review of similar procedures for other BWR plants, we see some benefit to adding further quantitative criteria for the detection of core T-H instabilities in these procedures. These procedures will be revised to include the quantitative core T-H '

oscillation detection criteria recommended in the November 1988 i j

BWROG letter entitled, " Interim Recommendation for Stability [

Actions," which was endorsed by Bulletin 88-07, Supplement 1.

i We hope this response provides the information necessary to ,

resolve the NRC's concern in this matter. If you have any j questions or require additional information, please contact us.  ;

r j Very truly yours,

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$ l DEN:cah 9

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cc: T. T Martin, Administrator, Region I, USNRC  ;

N. S. Perry, USNRC Senior Resident Inspector, LGS i i  !

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