Ajuda com update no hibernate

@Entity
@Table(name = "tb_ato_natureza", catalog = "db_dnaso", schema = "db_notas")
@SequenceGenerator(sequenceName="tb_ato_natureza_cd_ato_natureze_seq",allocationSize=1, initialValue=0, name = "tb_ato_natureza_cd_ato_natureze_seq")
@NamedQueries({@NamedQuery(name = "TbAtoNatureza.findByNmDivisor", query = "SELECT t FROM TbAtoNatureza t WHERE t.nmDivisor = :nmDivisor")})
public class TbAtoNatureza implements Serializable {
    private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY, generator="tb_ato_natureza_cd_ato_natureze_seq")
    @Basic(optional = false)
    @Column(name = "cd_ato_natureze", nullable = false)
    private Integer cdAtoNatureze;
    @Column(name = "nm_tabela_custa", length = 250)
    private String nmTabelaCusta;
    @Column(name = "nm_divisor", length = 250)
    private String nmDivisor;
    @JoinColumn(name = "cd_ato", referencedColumnName = "cd_ato")
    @ManyToOne
    private TbAto cdAto;
    @JoinColumn(name = "cd_natureza", referencedColumnName = "cd_natureza"  )
    @ManyToOne(cascade=CascadeType.ALL)
    private TbNatureza cdNatureza;
}

@Entity
@Table(name = "tb_ato", catalog = "db_dnaso", schema = "db_notas")
@NamedQueries({@NamedQuery(name = "TbAto.findAll", query = "SELECT t FROM TbAto t"), @NamedQuery(name = "TbAto.findByCdAto", query = "SELECT t FROM TbAto t WHERE t.cdAto = :cdAto"), @NamedQuery(name = "TbAto.findByNmAto", query = "SELECT t FROM TbAto t WHERE t.nmAto = :nmAto"), @NamedQuery(name = "TbAto.findByNmTabelaCusta", query = "SELECT t FROM TbAto t WHERE t.nmTabelaCusta = :nmTabelaCusta"), @NamedQuery(name = "TbAto.findByNmDivisor", query = "SELECT t FROM TbAto t WHERE t.nmDivisor = :nmDivisor")})
public class TbAto implements Serializable {
    private static final long serialVersionUID = 1L;
    @Id
    @Basic(optional = false)
    @Column(name = "cd_ato", nullable = false)
    private Integer cdAto;
    @Basic(optional = false)
    @Column(name = "nm_ato", nullable = false, length = 250)
    private String nmAto;
    @Column(name = "nm_tabela_custa", length = 250)
    private String nmTabelaCusta;
    @Column(name = "nm_divisor", length = 250)
    private String nmDivisor;
    @OneToMany(cascade = CascadeType.ALL, mappedBy = "tbAto")
    private Collection<TbAtoSelo> tbAtoSeloCollection;
    @OneToMany(mappedBy = "cdAto")
    private Collection<TbAtoIndicador> tbAtoIndicadorCollection;
    @OneToMany(mappedBy = "cdAto")
    private Collection<TbAtoDocumento> tbAtoDocumentoCollection;
    @OneToMany(mappedBy = "cdAto")
    private Collection<TbAtoNatureza> tbAtoNaturezaCollection;
}

@Entity
@Table(name = "tb_natureza", schema="db_notas")
@SequenceGenerator(sequenceName="tb_natureza_cd_natureza_seq",allocationSize=1, initialValue=0, name = "tb_natureza_cd_natureza_seq")
@NamedQueries({@NamedQuery(name = "TbNatureza.findByNrDiasPrevisto", query = "SELECT t FROM TbNatureza t WHERE t.nrDiasPrevisto = :nrDiasPrevisto")})
public class TbNatureza implements Serializable {
    @Transient
    private PropertyChangeSupport changeSupport = new PropertyChangeSupport(this);
    private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY, generator="tb_natureza_cd_natureza_seq") 
    @Column(name = "cd_natureza", nullable = false)
    private Integer cdNatureza;
    @Column(name = "nm_natureza", nullable = false)
    private String nmNatureza;
    @Column(name = "ds_natureza")
    private String dsNatureza;
    @Column(name = "nr_dias_previsto")
    private Integer nrDiasPrevisto;
    @Column(name = "nm_tabela_custa")
    private String nmTabelaCusta;
    @Column(name = "nm_modelo_documento")
    private String nmModeloDocumento;
    @Column(name = "nm_divisor")
    private String nmDivisor;
    @Column(name = "ic_revoga_documento")
    private Boolean icRevogaDocumento;
    @Column(name = "ic_retifica_documento")
    private Boolean icRetificaDocumento;
    @Column(name = "ic_central_cep")
    private Boolean icCentralCep;
    @Column(name = "ic_central_cesdi")
    private Boolean icCentralCesdi;
    @Column(name = "ic_informa_doi")
    private Boolean icInformaDoi;
    @Column(name = "ds_tipo_transacao_doi")
    private String dsTipoTransacaoDoi;
    @Column(name = "cd_pendencia_caixa")
    private Integer cdPendenciaCaixa;
    @JoinTable(name = "tb_titulo_natureza", schema="db_notas", joinColumns = {@JoinColumn(name = "cd_natureza", referencedColumnName = "cd_natureza")}, inverseJoinColumns = {@JoinColumn(name = "cd_titulo", referencedColumnName = "cd_titulo")})
    @ManyToMany
    private Collection<TbTitulo> cdTituloCollection;
    @JoinTable(name = "tb_exigencia_natureza", schema="db_notas", joinColumns = {@JoinColumn(name = "cd_natureza", referencedColumnName = "cd_natureza")}, inverseJoinColumns = {@JoinColumn(name = "cd_exigencia", referencedColumnName = "cd_exigencia")})
    @ManyToMany
    private Collection<TbExigencia> cdExigenciaCollection;
    @OneToMany(mappedBy = "cdNatureza")
    private Collection<TbIndicadorDocumento> tbIndicadorDocumentoCollection;
    @OneToMany(mappedBy = "cdNatureza")
    private Collection<TbDocumento> tbDocumentoCollection;
    @OneToMany(mappedBy = "cdNatureza", cascade=CascadeType.ALL)
    private Collection<TbAtoNatureza> tbAtoNaturezaCollection;
}

public TbNatureza salvarEditarNatureza(TbNatureza tbNaturezaBean) throws Exception {
        TbNatureza novaNatureza = new TbNatureza();

        if(tbNaturezaBean.getCdNatureza() == null){
            propBean.copyProperties(novaNatureza, tbNaturezaBean);
        
            naturezaDAO.persist(novaNatureza);
        }else{          
            naturezaDAO.update(tbNaturezaBean);
            propBean.copyProperties(novaNatureza, tbNaturezaBean);
        }
        return novaNatureza;

    }

tbNaturezaBean.setTbAtoNaturezaCollection(AtoNaturezaList);